LO 3.6: The student can predict how a change in a specific DNA or RNA sequence can result in
changes in gene expression.
SP 6.4: The student can make claims and predictions about natural phenomena based on
scientific theories and models.
Explanation: DNA or RNA sequences are constructed out of distinct nucleotide base pairs: A-T
(A-U for RNA sequences) and C-G. Nucleotide units are formed from nitrogen bases, sugars,
and phosphate groups. Covalent bonds hold the nucleotides together by forming a linear
molecule with both 3' and 5' ends, nitrogen base pairs, and the sugar phosphate backbone.
DNA is double stranded and RNA is single stranded. For a gene sequence to be expressed, the
mRNA has to take the message from the DNA to the ribosome where it then has tRNA bind to
amino acids and translation occurs and eventually the message is sent and the gene is
expressed. RNAi is used to help regulate gene expression, during mRNA transcription, by
inhibiting gene expression when the message does not need to be sent. By changing the DNA
or RNA sequence the message being sent will be expressed differently, ultimately altering the
final gene expression.
M.C. Question: The nucleotide ______ is replaced by ______ when DNA is translated into
mRNA.
A) adenine, thymine
B) guanine, cytosine
C) thymine, uracil
D) adenine, uracil
FRQ: Predict the results if the codon UGU was replaced by UGC during translation.
ANSWER KEY- LO 3.6
M.C. Question: The nucleotide ______ is replaced by ______ when DNA is translated into
mRNA.
A) adenine, thymine
B) guanine, cytosine
C) thymine, uracil
D) adenine, uracil
FRQ: Predict the results if the codon UGU was replaced by UGC during translation. How would
this affect the gene expression? What would happen if UGU was replaced by UGA? How would
this affect gene expression?
If UGU was incorrectly replaced with UGC, gene expression would not be affected. This
would be a silent mutation because UGU and UGC both code for the amino acid cysteine.
Either way cysteine would be expressed keeping the final message consistent with the
intended signal for gene expression. If UGU was replaced by UGA, the gene expression would
be altered. UGA is a stop codon and would stop the sequencing. By doing so, the information
being passed on will not be completed, leading to a change in gene expression or no gene
would be expressed for that particular sequence.
A) LO 2.3- The student is able to predict how changes in
free energy availability affect organisms, populations,
and ecosystems.
B) SP 6.4- Student should make claims and predictions
about natural phenomena based on scientific
theories and models.
C) Changes in free energy can ultimately affect an
organism’s ability to maintain homeostasis (body
temperature, pH levels, etc.) and their ability to
reproduce. Changes in the free energy availability
may alter a population’s size and may cause
disruptions to an ecosystem in regards to trophic
levels. If such alterations in the availability of free
energy does not benefit an organism, population, or
ecosystem then it can ultimately lead to the death of
organisms within a population and decrease energy
flow in the food chain.
D) The following image displays the trophic levels. What
group would face the most dramatic changes in free
energy if the plant population began to die out due to
drought?
a) Herbivores
E) Free energy is photons
that are converted to heat
via chained coupled
reactions passing energy
from one form to another.
a) Identify a form of free
energy and how it is used
in an organism. Explain
how changes in the free
energy would affect the
organism.
Answer Key
Multiple Choice
Free Response Question
• Correct Answer: D) All the above
• If a plant population faced a
drought, such as a grassland, then
all of the consumer populations
would be affected. Herbivores
that eat the plants would not
obtain enough energy or
nutrition, being that they now
have limited resources, which
means the negative effect of
decreasing free energy availability
would continue to affect
populations at higher trophic
levels.
•
A) A main source of free energy
include ATP which is used to drive
biological processes such as
metabolism. ATP transports
chemical energy within the cells for
catabolic or anabolic reactions to
occur. If the organism cannot
produce or accumulate ATP then it
will not have the energy to power
its metabolism. For instance,
glucose important for cellular
respiration, but if an organism has
too high glucose levels, it can cause
the metabolic reactions to slow
down and overall damage the cells.
LO 4.13: The
student is able
to predict the
effects of a
change in the
community’s
populations on
the community.
SP 6.4:The student can make claims and predictions about natural phenomena based on
scientific theories and models.
Explanation: There are many ways in which a population can change overtime it can be by
natural selection which can be through seasonal changes, favorable characteristics
accumulating over generations in a species, as well as how much of the population size
the environment can support of the population. New genes and new alleles originate
only by mutations which in most cases happens in somatic cells and only mutations in cell
lines that produce gametes can be passed to offspring. There are different types of
mutations for example point mutations which have little effect because they don’t change
the protein’s amino acid composition, but can have a significant impact as in sickle cell
disease. There are also duplication mutations that delete, disrupt, or rearrange many loci
which are almost certain to be harmful but in some occasions can be beneficial.
Bottleneck effect is when a disaster happens by a sudden change in the environment and
the few survivors gene pool may not be the same as the original population’s gene pool.
When a few individuals become isolated from a later population, this smaller group may
establish a new population this is the founder effect.
M.C. Question: There are mice that live on a mountain and during the day they usually go out
to find their food. Black, white, and grey mice reside on the mountain, but the rocks on which
they step on are grey. There are many different types of birds that fly over the mountain trying
to find their food which mainly consist of the mice that live on the mountain. It is preferable for
the mice to be grey which means that white and black mice are selected against because they
can be easily be seen by the birds up above. Which type of selection does this mostly
represent?
A)
B)
C)
D)
Mutations are the source
of all heritable variation.
Directional Selection
Disruptive Selection
Stabilizing Selection
Heterozygote Advantage
Learning Log/ FRQ-style Question: A)The allele for free earlobes is dominant
over the allele for attached earlobes. In a population of 1,000 individuals, 360
shows the recessive phenotype. How many individuals would you expect to be
homozygous dominant and heterozygous for this trait? B) Which five conditions
for non-evolving populations are rarely met for long in nature?
Answer
Key- LO
4.13
There are mice that live on a mountain and during the day they usually
go out to find their food. Black, white, and grey mice reside on the
mountain, but the rocks on which they step on are grey. There are many
different types of birds that fly over the mountain trying to find their
food which mainly consist of the mice that live on the mountain. It is
preferable for the mice to be grey which means that white and black
mice are selected against because they can be easily be seen by the
birds up above. Which type of selection does this mostly represent?
A)
B)
C)
D)
Directional Selection
Disruptive Selection
Stabilizing Selection
Heterozygote Advantage
A) The allele for free earlobes is dominant over the allele for attached
earlobes. In a population of 1,000 individuals, 360 shows the recessive
phenotype. How many individuals would you expect to be homozygous
dominant and heterozygous for this trait? B) Which five conditions for
non-evolving populations are rarely met for long in nature?
aa
q
²
.3
6
360 =
aa
480 =
Aa
160 =
AA
1)
a
A
q
p
.
6
.4
1-
A
A
p
²
.1
6
A
a
2
p
.4
q
8
2)
3)
4)
5)
Extremely Large
Population Size.
No gene flow.
No Mutations.
Random mating.
No natural selection.
LO 3.30: The student is able to use representations and appropriate models to describe how
viral replication introduces genetic variation in the viral population.
SP 1.4: The student can use representations and models to analyze situations or solve problems
qualitatively and quantitatively
Explanation: Viral replication occurs in two processes: One being the lytic cycle, and the other
being the lysogenic cycle. The lytic cycle and lysogenic cycle are very similar in that they involve
similar stages:
1)The phage infects a host bacteria cell by attaching itself to the membrane
2)The virus then injects its respective DNA into the host cell
3)The virus’s DNA is either integrated into the host cell’s DNA or the host cell’s DNA is digested
in order to code for the virus’s given traits
4)The host cell then begins replicating the virus that initially infected it
5)These replicated parts of the virus are then assembled within the host cell
6)The host cell eventually lyses due to all of the progeny viruses built up within
7)The process repeats as the new viruses find new host cells to infect
The main difference being that the lysogenic cycle doesn’t lyse the host cell, instead the
integration of the virus’s DNA is passed on as the cell goes through mitosis.
These two processes of viral replication are highly efficient due to the quickness that they occur;
this quickness also results in genetic variation within the viral population because the above
processes lack error checking mechanisms, which result in various mutations. The lysogenic
cycle also introduces genetic variation because the integration of the virus DNA into the host
cell’s DNA can result in new traits that are passed on to the progeny virus.
M.C. Question:
The section labeled A in the figure is the lytic cycle, and the
section labeled B is the lysogenic cycle. Based on the two
processes, how do they each introduce genetic variation within
the viral population?
A)Crossing over of viral DNA occurs within each cycle resulting in
mutations and the introduction genetic variation.
B)The integration of viral DNA and host cell DNA in the lytic cycle
cause mutations resulting in genetic variation, while the lack of
error checking mechanisms in the lysogenic cycle cause
mutations resulting in genetic variation.
C)Random mating of the viruses while inside the the host cell
causes the mixing of alleles resulting in genetic variation.
D)The integration of viral DNA and host cell DNA in the lysogenic
cycle cause mutations resulting in genetic variation, while the
lack of error checking mechanisms in the lytic cycle cause
mutations resulting in genetic variation.
# Of Deaths (in millions)
Deaths Caused by Virus X
100
80
60
Deaths
40
20
0
1500
1600
1700
1800
1900
2000
Year
Learning Log/FRQ-style Question:
The chart given is the graph of deaths (in millions) caused by Virus X in the USA from year 1500
to year 2000. Based on the line graph answer the following questions:
a)Describe one of the processes in which Virus X infected the host cells of the victims.
b)Give two possible reasons why the deaths caused by Virus X increased exponentially from
year 1500 to year 1700.
c)Give two possible reasons why the deaths caused by Virus X decreased from year 1700 to year
1900.
ANSWER KEY – LO 3.30
The section labeled A in the figure is the lytic cycle, and the section labeled B is the lysogenic
cycle. Based on the two processes, how do they each introduce genetic variation within the viral
population?
A)Crossing over of viral DNA occurs within each cycle resulting in mutations and the introduction
genetic variation.
B)The integration of viral DNA and host cell DNA in the lytic cycle cause mutations resulting in
genetic variation, while the lack of error checking mechanisms in the lysogenic cycle cause
mutations resulting in genetic variation.
C)Random mating of the viruses while inside the the host cell causes the mixing of alleles
resulting in genetic variation.
D)The integration of viral DNA and host cell DNA in the lysogenic cycle cause mutations
resulting in genetic variation, while the lack of error checking mechanisms in the lytic cycle
cause mutations resulting in genetic variation.
ANSWER KEY – LO 3.30 Continued
The chart given is the graph of deaths (in millions) caused by Virus X from year 1100 to year
1600. Based on the line graph answer the following questions:
a)Describe one of the processes in which Virus X infected the host cells of the victims.
b)Give two possible reasons why the deaths caused by Virus X increased exponentially from year
1500 to year 1700.
c)Give two possible reasons why the deaths caused by Virus X decreased from year 1700 to year
1900.
a)One of the processes in which Virus X can infect the host cells of the victims is through the
lytic cycle. The lytic involves 7 steps: 1)The phage infects a host bacteria cell by attaching itself
to the membrane. 2)The virus then injects its respective DNA into the host cell. 3)The host cell’s
DNA is digested, while the virus’s DNA begins coding for its given traits. 4)The host cell then
begins replicating the virus that initially infected it. 5)These replicated parts of the virus are then
assembled within the host cell 6)The host cell eventually lyses due to all of the progeny viruses
built up within. 7)The process repeats as the new viruses find new host cells to infect.
b)One possible reason the why the deaths caused by Virus X increased exponentially from year
1500 to year 1700 in the USA is due to the increased rate of successful infection. As Virus X
continued to replicate itself through the lytic cycle, more and more progeny viruses were
created further increasing the spread of the virus as it became more prominent within the
victim’s population. Another reason could be due to genetic variation within the viral
population. At some point from year 1500 to year 1700, Virus X could’ve gone through a
mutation as result of the lack of error checking mechanisms in the virus’s replication process. As
a result of this mutation, a new strand of Virus X was more potent and fatal causing more deaths
in the population of the victims.
ANSWER KEY – LO 3.30 Continued
c) One possible reason why the deaths caused by Virus X decreased from year 1700 to year 1900
in the USA is due to a lack of genetic variation. Mutations within the viral populations stopped
occurring, which gave the immune system of the victims to eventually recognize the virus and
combat it until an immunity was built. Another reason why the deaths caused by Virus X
decreased in these years in the USA is the creation of vaccine. A vaccination would explain the
the decrease in death caused by Virus X because it would expose those who were given the
shots to a weaker form of the virus, so the victim’s immune system can remember and create
and immunity to that same strand of Virus X.
Learning Objective Focus Project
•
•
•
•
•
•
•
•
•
LO 4.26: The student is able to use theories and models to make
scientific claims and/or predictions about the effects of variation within
populations on survival and fitness.
SP 6.4: The student can make claims and predictions about natural
phenomena based on scientific theories and models.
Explanation: In Darwin's theory of natural selection, individuals in a
population will exhibit variations in their heritable traits, and those traits
that are best suited to the environment tend to produce more offspring
than those with variations that are less well suited. Natural selection
participates in the alteration of genotypic and as a result alters phenotypic
frequencies, sometimes in ways that suit the organism to its environment.
Natural Selection does this in three ways: Directional selection, Disruptive
selection, and Stabilizing selection. In directional selection, most common
when the environment is changing, naturals selection favors variant at one
phenotypic extreme. The environment may favor dark furred organisms
over organisms that have lighter fur. The environment may contain dark
rocks. The second type of selection is disruptive selection in which both
phenotypic extremes either very light or very dark are favored over
intermediate phenotypes. In stabilizing selection, the environment favors
intermediate phenotypes over the two extreme phenotypes.
M.C. Question: Based on the given genotypes for fur color and assuming
polygenic inheritance, the alleles A and B contribute one unit of darkness
to the phenotype while being incompletely dominant to the alleles a and
b. Considering the following genotypes: aaBB, AABB, aaBb and aabb.
Which two genotypes would have the most likely chance of surviving
based on graph A.?
A. aaBB and aaBb
B. AABB and aabb
C. aaBb and aabb
D. AABB and aaBb
Learning Log/ FRQ-style Question: Natural Selection can alter a
populations genetic composition. Identify and describe two other
methods of genotypic alteration. How does it come about.? How does
each impact variation in a population.? For one of the methods identify
and describe its subtypes and create a scenario of these subtypes.
Answer Key-LO 4.26
•
•
•
•
•
•
Based on the given genotypes for fur color and assuming
polygenic inheritance, the alleles A and B contribute one
unit of darkness to the phenotype while being
incompletely dominant to the alleles a and b. Considering
the following genotypes: aaBB, AABB, aaBb and aabb.
Which two genotypes would have the most likely chance of
surviving based on graph A.?
A. aaBB and aaBb
B. AABB and aabb
C. aaBb and aabb
D. AABB and aaBb
The correct answer is B. By looking at graph A the student
should be able to identify that a disruption selection graph
was being displayed in which organisms with phenotypes
on both extremes will be supported. Also that is the only
type of graph that will support two variants of phenotype.
AABB is the darkest phenotype and aabb is the lightest
phenotype, making them the two phenotypic extremes
and the two that will most likely survive based on graph A.
•
Natural Selection can alter a populations genetic composition.
Identify and describe two other methods of genotypic alteration. How
does it come about.? How does each impact variation in a
population.? For one of the methods identify and describe two
situations that increase the likelihood of this method occurring.
•
One method of alteration in genotypic alteration is genetic drift in
which alleles unpredictably fluctuate. Genetic drift tends to reduce
genetic variation through the loss of alleles in the gene pool. The two
situations that increase the likelihood of genetic drift id the founder
effect and the bottle neck effect. The bottleneck effect in most cases
involves a sudden change in the environment or natural disaster that
cause the population to rapidly reduce in number. The few members
who do survive through the bottleneck will not be representative of
the original population. This decreases genetic variation leading to an
increased chance of genetic drift. The second situation that increases
the chances of genetic drift is the founder effect. It involves
individuals becoming isolated from a larger population and this
smaller group establishes a new population in which the gene pool
does not reflect the original population. The founder effect can be
detrimental to populations in that the same alleles are being passed
around possibly leading to genetic disease. The other method of
genetic alteration is gene flow which simply involves that addition and
subtraction of alleles from populations. Gene flow tends to reduce
genetic variation in that alleles often times flow in between
populations and therefore reduce their differences.
LO 3.10: LO 3.10 The student is able to represent the connection between meiosis and
increased genetic diversity necessary for evolution.
SP 7.1: The student can connect phenomena and models across spatial and temporal scales.
Explanation: Meiosis is a reduction division that utilizes fertilization to increase genetic diversity in sexually
reproducing organisms. Within Meiosis, each of the gametes receive a completely haploid or 1n set of
chromosomes. This is done so when the homologous chromosomes (one homologue from both the maternal and
paternal parent) are paired and then orientated randomly within the cell. Once separated, these gametes hold a set
of haploid chromosomes made up of both parent’s chromosomes. Furthermore, when the two gametes from the
first division complete the second division, they “cross over” homologous chromatids so they can exchange genetic
material. This increases the genetic variations within the resulting gametes of this division. Once fertilization later
fuses two gametes together, the process of meiosis that had previously occurred in each has provided new
combinations of genes within the resulting diploid zygote. Because each gamete held unique combinations on
genes within each other, the resulting zygote has an even more unique set of chromosomes that will provide for an
increase of genetic variation within the organism’s population.
M.C. Question:
Within what phase of Meiosis does the process of crossing over occur?
A) Metaphase I
B) Anaphase I
C) Prophase I
D) Metaphase II
E) Telophase II
Learning Log/FRQ-style Question:
Name and explain two key mechanisms that
Meiosis carries out that specifically contribute
to the genetic variation within the offspring
produced.
ANSWER KEY– LO 3.10
During what phase of Meiosis does the process of crossing over occur?
A) Metaphase I
B) Anaphase I
C) Prophase I
D) Metaphase II
E) Telophase II
Name and explain two key mechanisms that Meiosis carries
out that specifically contribute to the genetic variation
within the offspring produced.
Within Meiosis in Prophase I, homologous chromosomes
cross over. This allows sections of the two inner sister
chromatids to switch, while the out two chromatids stay
the same. This new combination of alleles within these
sister chromatids produce a unique chromatids of alleles.
Because of this, the resulting zygote has it’s own diverse
genetic code.
Meiosis also only allows one of each chromosome within
the gametes produced, doing so at random from the
homologous pairs. By producing 4 unique gametes that
later join with another unique gamete, the possibilities of
allele combinations due to the randomly chosen
chromosomes are endless. This also allows for the offspring
to be genetic diverse and variant from its parents.
LO 3.4: The student is able to describe representations and models illustrating how genetic information is translated into polypeptides. [See SP 1.2]
SP 1.2: The student can describe representations and models of natural or man-made phenomena and systems in the domain.
Explanation: Translation produces proteins. After transcription where the DNA template was transcribed into a mRNA strand, the strand is fed through the
ribosome where tRNA, which has a complementary anticodon to each mRNA codon, translates it into a polypeptide. In the ribosome, the three steps of
translation take place: initiation, elongation and termination. First, the small subunit attaches to the mRNA strand and the start codon (AUG) is recognized;
GTP is hydrolyzed to allow the large and small subunit to bind together and mRNA to pass through. In elongation, the anticodon of the tRNA base pairs with
the MRNA codon at the A site and a peptide bond forms. The mRNA strand is fed through the A site, P site and E spite before It leaves. When a stop codon
(UAA, UAG, or GUA) is reached, the large and small subunits disband, not immediately, and tRNA is removed from the binding sites and the polypeptide is
freed.
MC Question: Figure 17.19-4 depicts the process of translation. Which of the following
statements regarding the process are true?
I. When a stop codon is reached, a release factor protein enters the A site thus
disbanding the complex and releasing the polypeptide.
II. In the first step of initiation, the large ribosomal subunit binds to the small subunit and
the mRNA strand before the initiator tRNA, which has the methionine amino
acid.
III. The codon UAG initiates translation.
IV. The peptide bond forms between the amino acid of the tRNA in the A site and the
polypeptide.
A) I only B) II , III, and IV C) II and IV
D) I and IV
FRQ:
The central dogma describes a two step process in
which genetic information flows from DNA to RNA to
protein. In the figure above, identify and outline the
process depicted. How does the central dogma relate
to the figure?
Cyclohexamide, a protein synthesis inhibitor, inserts a
premature stop codon in the mRNA strand. How would
this affect the process depicted above?
ANSWER KEY – LO 3.4
MC Question: Figure 17.19-4 depicts the process of translation. Which of the following statements regarding the process are true?
I. When a stop codon is reached, a release factor protein enters the A site thus disbanding the complex and releasing
the
polypeptide.
II. In the first step of initiation, the large ribosomal subunit binds to the small subunit and the mRNA strand before the
initiator
tRNA, which has the methionine amino acid.
III. The codon UAG initiates translation.
IV. The peptide bond forms between the amino acid of the tRNA in the A site and the polypeptide.
A) I only
B) II , III, and IV
C) II only
D) I and IV
FRQ:
The central dogma describes a two step process in which genetic information flows from DNA to RNA to protein.
In the figure above, identify and outline the process depicted. How does the central dogma relate to the figure?
Cyclohexamide, a protein synthesis inhibitor, inserts a premature stop codon in the mRNA strand. How would this
affect the process depicted above?
The process depicted is the second step of the central dogma (DNA
RNA
Protein), translation. Translation takes place in the
ribosome and is comprised of 3 steps: initiation, elongation, and termination. During initiation, the initiation complex is formed with the
hydrolysis of GTP. The small subunit of the ribosome binds to the mRNA strand, then the tRNA recognizes and binds to the start codon
(AUG), and finally the large subunit binds to complete the complex. At the next step, elongation, the tRNA has a complementary
anticodon for the codon on the mRNA strand. Each codon is read in triplets and the tRNA brings along the correct amino acid for each
codon. The tRNA move through 3 sites in order of A, P and E. Finally, a stop codon (i.e. UAG) is recognized and a release protein binds to
the A site and the complex disbands. The result is a polypeptide/protein.
If there is a premature stop codon in the mRNA strand, then the complex will be disbanded early. The amino acid sequence that was
intended to be produced wasn’t made; thus a different protein is produced. Because structure defines function, the different protein will
not have the intended function, thus resulting in a different phenotype. This may have adverse effects including diseases and disorders.
L.O. 4.22 : The student is able to construct explanations based on evidence of how variation in molecular units provides
cells with a wider range of functions.
S.P 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices
•
Explanation: There are four major macromolecules that make up molecular units: Carbohydrates, Proteins, Lipids, and Nucleic acids. These
polymers consist of monomers which contribute to the structure of these macromolecules and therefore their function. For instance, a pattern
of amino acids make up and code for a specific , unique protein and a polypeptide is a polymer of amino acids. There are 20 amino acids of
proteins. Proteins have four levels of structure: Primary, Secondary, Tertiary, and Quaternary. The Primary consist of an amino acid
sequence, the secondary is based on the hydrogen bonds, and the tertiary have disulfide bridges and a 3D shape based on the amino acid
sequence in the primary structure while the quaternary consist of polypeptide subunits .A change in the specified amino acids or a mutation
in the needed protein will change the original function. An example of this is the different types of hemoglobin. Hemoglobin is a quaternary
structures protein made up of up different amino acids and mutations in globin genes cause changes in the amino acids that make up the
globin protein. Hemoglobin consist of four molecules. When there is a mutation in these molecules (Alpha Chains and Beta Chains) it leads
to variant hemoglobin. These types of variant hemoglobin create abnormal blood cells. One disease that
can derive from
Aminvariant hemoglobin
+H N
3
o
acid
is Sickle-Cell Anemia because of a mutation in Hemoglobin S.
Amin
M.C Question: Which of the following
structural levels will be most affected by a
problem in hydrogen bonding in a protein?
A)Primary
B)Secondary, Quaternary
C) Tertiary
D) B & C
• FRQ-Style Question:
Everything made in the cell derives from
macromolecules. These macromolecules make
up important structures in the cell to aid in
cellular processes. How are polymers added to
carbs? How does this broaden the molecules
function in cells?
o end
Pro
Thr
Gly
Gly
Thr
Gly
Glu
Seu
Lys
Cys
Pro
Leu
Met
Val
Lys
Val
Leu
Asp
Ala
Arg
Val
Gly
Ser
Pro
Ala
Glu
Lle
Asp
Thr
Lys
Ser
Tyr
Trp
Lys
Ala
Leu
Gly
lle
Ser
Pro
Phe
His
Glu
His
Ala
Glu
Val
Thr
Phe
Val
Ala
Asn
Thrlle
Asp
Ala
Tyr
Arg
Ser Arg
Ala
Pro
Gly
Leu
Leu
Ser
Pro
Tyr
Ser
Tyr
Ser
Thr
Thr
Ala
Val
Glu
Val
Lys
Thr
Pro
Asn
co
o–
Carboxyl end
subun
its
Poly
pept
ide
chai
n
Col
 lag
Chainen
s
Iron
Heme

Chains
Hemo
globin
Answer Key L.O 4.22
•
Which of the following structural
levels will be most affected by a
problem in hydrogen bonding in a
protein?
A)Primary
B)Secondary, Quaternary
C) Tertiary
D) B & C
Polymers are added to car bs through
dehydration synthesis. Dehydration
Synthesis removes a water molecule and
forms new bonds. This broadens the
molecules functions in cells because it
helps aid in structural support i.e.
cellulose and also aids in giving nutrients
to the cell. Starch is used to feed plants
for example and bacteria digest cellulose.
L.O 3.24: The student is able to predict how a change in genotype, when expressed as a phenotype,
provides a variation that can be subject to natural selection.
S.P 6.4: The student can make claims and predictions about natural phenomena based on scientific theories and
models.
S.P 7.2:The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across
enduring understandings and/or big ideas.
Changes in genotypes, whether they be from mutation or evolution, alter the phenotype through changing of genetic makeup
changing the protein production. Many times this change in genotype gives a competitive advantage because of the
environmental conditions the organism lives in. The organism because of this change in genotype has an higher chance of
survival and reproduction of fertile offspring. This will often lead to the change in genotype being passed down many
generations and eventually due to natural selection change the genetic makeup of the whole population leading to evolution.
This is the reason many antibiotics such as penicillin stop working in humans. The bacteria mutates a antibiotic-resistant gene
causing a change in genotype which provides a variation that gives it an edge. Natural selection occurs and the cells with this
advantage reproduce the most and survive the best causing eventually all bacterial cells to have the antibiotic resistant gene.
M.C.Q- All of the following are sources of variation in a population except
A- mutation
B- habitat fragmentation
C- polyploidy
D- crossing over
FRQ- The exchange of bacterial information leads to rapid circulation of phenotypes through a population of bacteria which can help
a species of bacteria survive and the phenotype be subject to natural selection. Describe two mechanisms in which bacterial
information is transferred between cells.
Answer Slide
• B
• FRQ answer- Two ways bacterial information is
transferred between cells is transformation and
conjugation. Transformation is the direct uptake,
incorporation and expression of exogenous genetic
material from its surroundings. Bacterial
conjugation is the transfer of genetic material
between bacterial cells by direct cell to cell contact
or by a bridge like connection between two cells.
LO 2.28 The student is able to use representations or models to analyze quantitatively and qualitatively the effects of disruptions to dynamic
homeostasis in biological systems. [See SP 1.4]
SP 1.4 The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively
Explanation: Homeostasis refers to the effort of an organism to keep its environment in a steady state. Organisms must have an adaptive response to variation in their
environments if they are to survive and prosper. Disruptions to homeostasis and an organisms response is a recurrent theme within the study of biology. These alterations
and adaptations can be modeled with a variety of visual aids. Homeostatic changes may occur on the molecular level and include alterations in an organisms biochemical
environment such as changes in pH, oxygen content, nutrient availability, effects of ionizing radiation, or change in temperature. This can be represented by diagrams and
models of molecular structures, flow charts of biochemical reactions, and illustrations demonstrating the flow of molecules across cellular membranes. Changes in
homeostasis may also occur at the cellular level such as the introduction of infectious organisms and the immune response to foreign agents. Disruptions to an organisms’
environment also occur at the macroscopic level with alterations in ecosystems such as habitat loss, pollution, drought, and the introduction of invasive species. These
effects are demonstrated using tabular or graphical data in addition to flow charts and diagrams.
Multiple Choice Question: The oxygen dissociation curve shows the homeostatic relationship between the binding of oxygen to hemoglobin and the partial pressure of oxygen
(pO2) in the blood. Jimmy’s oxygen saturation of hemoglobin falls from 80% to 40%. The most likely explanation for this would be:
A) a drop in blood pH
B) an increase in blood pH
C) a decrease in the partial pressure of oxygen in the blood
D) increase in the partial pressure of oxygen in the blood
FRQ-Style Question: When a person is exercising and oxygen becomes scarce, muscle cells must resort to anaerobic metabolism in order to maintain energy production and
homeostasis within the cells. Name and describe the process that the muscle cells use and include all molecules involved in this process. Also, include a labeled model of the
process in your answer.
Multiple Choice Question Response: The correct answer is choice C. This answer choice is correct because as the partial pressure decreases, an increase of oxygen is released
into the blood stream. A is incorrect because although a decrease in pH does increase the amount of oxygen released, it is not enough for a change as large as 80% to 40%. B is
incorrect because an increase in the pH level increases the amount of oxygen bound to hemoglobin. D is incorrect because an increase in the partial pressure also increases the
amount of oxygen bound to hemoglobin.
Further explanation --Hemoglobin binds to oxygen and is responsible for the majority of the oxygen carrying capacity of blood. Changes in the partial pressure of oxygen in
blood (pO2) and pH produce conformational changes in the hemoglobin molecule that affects oxygen binding affinity to hemoglobin. This binding and release of oxygen is
represented by the dissociation curve of hemoglobin. This curve shows the relationship between pO2 and hemoglobin saturation. It also demonstrates the effect of changes in pH,
known as the Bohr effect..
FRQ-Style Question Response: The process being used is lactic acid fermentation. After glycolysis occurs in the cytosol, pyruvate is produced as well as a net of two ATP
molecules, and two NADH. In the absence of oxygen, glycolysis is able to continue as long as there is NAD+ available. To achieve a steady supply of NAD+ in the anaerobic
environment, the organism uses a process known as lactic acid fermentation, in which pyruvate is converted into lactic acid and NADH is recycled back to NAD+.
LO 1.7: The student is able to justify data from mathematical models based on the
Hardy-Weinberg equilibrium to analyze genetic drift and the effects of selection in
the evolution of specific populations
SP 2.1: The student can justify the selection of a mathematical routine to solve
problems
• Explanation: In nature, evidence of natural selection and genotypic frequencies are proven through the HardyWeinberg Principle shown below in the illustration. Mathematically the equation states that the allelic frequency of the
homozygous dominant genotype plus the frequency of the heterozygous dominant genotype and the frequency of the
homozygous recessive genotype is equivalent to 1. This equation is able to prove whether or not a population is evolving.
Evolution occurs through genetic genetic drift, which is the change of the of a frequency of a gene allele due to the random
mating on an organism. When a population isn't undergoing this change it is explained as Hardy Weinberg equilibrium and
for a population to be in equilibrium it must fail to experience the effects of mutations, genetic drift, gene flow, natural
selection, and nonrandom mating. Through following the mathematical routine of the Hardy-Wienberg Principle, scientists
are able to prove that all life on Earth is evolving slowly over time.
M.C Question:
In a sampled population, you observe that the recessive homozygous genotype
frequency is 36%. Using this information, find both the A allele and the frequency
of the Aa genotype
A) A = .4 , Aa= 48%
B) A= .3, Aa= 46%
C) A= .2, Aa= 34%
D) A= .6 Aa= .24%
Learning Log/FRQ-Style Question:
Do the following involving the Hardy-Weinberg Principle:
A) Explain the necessary conditions for allelic frequencies (p and q) to remain
constant without change from generation to generation.
B) Use the Hardy-Weinberg principle to calculate the frequencies of both the
alleles and the genotypes of a population of 10,000 flies, in which 2000 flies are
black and 8000 flies are white. White being dominant and black being reccesive.
C) If the flies were introduced to a new species of prey that favored white flies over
black flies, what do you think would happen to the dominant allele after several
generations?
ANSWER KEY-LO
1.7
M.C Question:
In a sampled population, you observe that the recessive homozygous genotype frequency is
36%. Using this information, find both the A allele and the frequency of the Aa genotype
A) A = .4 , Aa= 48%
B) A= .3, Aa= 46%
C) A= .2, Aa= 34%
D) A= .6 Aa= .24%
Do the following involving the Hardy-Weinberg Principle:
A) Explain the necessary conditions for allelic frequencies (p and q) to remain constant without
change from generation to generation.
B) Use the Hardy-Weinberg principle to calculate the frequencies of both the alleles and the
genotypes of a population of 10,000 flies, in which 2000 flies are black and 8000 flies are white. White
being dominant and black being recessive.
C) If the flies were introduced to a new species of prey that favored white flies over black flies, what do
you think would happen to the dominant allele after several generations?
A) For allelic frequencies to remain constant without change, the population must be in equilibrium.
This means that the population must large, it must experience no mutations, it must undergo no genetic
drift, the mating of organisms must be random, no natural selection and no gene flow from generation
to generation to exist. If these criteria are met then the population is defind as being in Hardy-Weinberg
equilibrium.
B) White allele: .8
Black allele: .2
WW= .64
Ww=.32
ww=.04
C) Even though the white genotype wouldn't disappear completely, the recessive black allele would
become dominate after several generations, since natural selection due to the newly introduced
predator favors black over white.
LO 3.20 The student is able to explain how the regulation of gene expression is essential for the processes
and structures that support efficient cell function.
SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices.
This learning objective was covered in Chapter 21: Genetic Basis of Development. We
discussed how cells differentiate; signals trigger regulatory genes to activate, transcription
factors are made which activate other genes, which produce the proteins that determine cell
type, structure, and function. In Figure 21.9, biologists cultured stem cells in different
Embryonic stem cells
Adult stem cells
conditions, which resulted in different final cell functions.
Early human embryo
From bone marrow
~~~
MCQ: Signal A and Signal B communicate with embryonic stem cells. Signal A
triggers one type of transcription factors to activate and Signal B triggers another,
unrelated type of transcription factors to activate. If each cell in the area is reached
by either Signal A or Signal B, what will be the result?
at blastocyst stage
(mammalian equivalent of blastula)
in this example
Totipotent
cells
Pluripotent
cells
A) The cells will differentiate into different types of cells.
B) The cells will transcribe at different rates.
C) The signal transduction pathways will convert both signals to produce the same
response.
D) Signal A will cause cells to produce more of Signal A and Signal B will cause cells
to produce more of Signal B.
E) The area of cells will either respond to Signal A or Signal B, but not both.
FRQ: All diploid cells in a human carry the same genetic material.
Explain the process of how cells develop to have different structures
and functions. Identify one type of cell that could develop from an
embryonic stem cell and describe how the specific function of the cell
is acquired.
Liver cells
Nerve cells
Blood cells
Answer Key
MCQ: A) The cells will differentiate
into different types of cells.
Robbie Wooten
Mr. Mercer
2nd period
• FRQ: (5 points total)
– Explain the process: signals activate regulatory genes and transcription factors
(1 point), which activate the genes specific to that signal (1 point). These
specific genes produce the proteins (and transcription factors to produce more
proteins) that determine specific cell type, structure, and function (1 points).
Bonus point to describe the irreversible or defining nature of this cell
differentiation.
– Identify a type of cell that could develop from an embryonic stem cell: Any
somatic cell, including liver cells, nerve cells, muscle cells, gamete-source cells,
blood cells, etc. (1 point). Describe how the specific function is acquired: must
list a protein or structure of the cell and mention activation of genes in cell
differentiation (1 point).
LO 3.32 The student is able to generate scientific questions involving cell communication as it relates to the
process of evolution.
SP 3.1 The student can pose scientific questions.
Explanation: Cells have the ability to communicate with each other by sending and receiving different signals.
Communication occurs through signal transduction pathways, which allow certain bacterial cells in single-celled
organisms to have a certain response. In multi cellular organisms, cell communication allows for them to
coordinate all of their activities, such as the endocrine system. So how do these two instances of cell
communication relate to the process of evolution? Microorganisms have been able to use cell to cell
communication to interact with their environment and evolve. In single cell organisms, cell communication
creates an environmental response, an example is Quorum sensing with bacteria. In multi cellular organisms,
epinephrine is related to glycogen breakdown and the release of glucose.
M.C. Question: Which of the following statements concerning cell
Communication is not true?
A) Signals may come from the environment, as well as
other cells
B) Signals usually pass from protein to protein
C) Each cell can only respond in one way once its target
molecule reaches it
D) Each cell receives a complex combination of signals
FRQ-style essay
Cellular communication allows for millions of cells to work
together in order to carry bodily processes that to required
For survival. For the following scenarios of cell communication
given, explain how each is important to sustaining life
A. Receiving and processing info from the environment
B. directly communicating with one another
Answer Key-LO 3.32
Which of the following statements concerning cell
Communication is not true?
A) Signals may come from the environment, as well as
other cells
B) Signals usually pass from protein to protein
C) Each cell can only respond in one way once its target
molecule reaches it
D) Each cell receives a complex combination of signals
Cellular communication allows for millions of cells to work
together in order to carry bodily processes that to required
For survival. For each the following scenarios of cell communication
given, explain how each is important to sustaining life
A. Receiving and processing info from the environment
B. directly communicating with one another
A)
B)
Cells would not be able to survive if they were not able to receive and
process information from the environment. Through communication, they
are able to detect changes in the availability of nutrients so they can make
the necessary adjustments in the organism to obtain to help obtain the
food that is needed. They are also able to detect changes in light
availiability to coordinate gene expression, an example is quorum sensing,
which allows bacterial cells to stimulate a response correlated to
population density.
Cells can also communicate with each other and these types of
interactions are mainly seen in multicellular organisms. Cell signaling
allows for cells to bind together and form specialized groups for specialized
functions. These functions include joining together to form muslces, blood
and brain tissues.
LO 1.24 The student is able to describe speciation in an isolated population and connect it to
change in gene frequency, change in environment, natural selection and/or genetic drift.
SP 7.2 The student can connect concepts in and across domain(s) to generalize or extrapolate in
and/or across enduring understanding and/or big ideas.
•
Explanation: A species genes are greatly influence by the environment they live in. Due to changes in the
environment, changes in gene frequency, natural selection, speciation, and/or genetic drift can occur. This is due to
adaption and reproduction of the fittest. Speciation can happen due to many factors that isolate organisms or
populations of the same species such as geographic isolation, bottleneck effect, founder effect, and other
mechanisms such as polyploidy. Changes in environment is the main thing that causes speciation in populations all
over the world. Whether it is a change in environment that changes a “fit” phenotype or a natural disaster, changes
in the gene pool can alter gene frequencies and can cause speciation.
•
Multiple Choice:
Which of the following would NOT characterize the situation if a flood killed the majority of a population of deer?
A. A disaster like this reduces the population size so that the surviving population is not representative
of the original population, known as the founder effect.
B. The gene pool would shift in the population, eventually changing the phenotypes in some of the deer.
C. Genetic drift would occur due to the small size of the small size of the population.
D. The surviving deer would pass on their more fit genes to the next generations,
making the population better fit to survive another flood.
FRQ:
Suppose you have a population of tree frogs, in which the favored homozygous dominant
genotype produces an all green color, the heterozygous genotype makes a green
and black spotted color. Describe an instance in which the favored genotype would change.
What causes this change? What is it’s affect on the gene pool of the population? What are the
advantages of having a favored phenotype?
Answer Key- LO 1.24
Which of the following would NOT characterize the situation if a flood killed the majority of a population of deer?
A. A disaster like this reduces the population size so that the surviving population is not representative
of the original population, known as the founder effect.
B. The gene pool would shift in the population, eventually changing the phenotypes in some of the deer.
C. Genetic drift would occur due to the small size of the small size of the population.
D. The surviving deer would pass on their more fit genes to the next generations,
making the population better fit to survive another flood.
(It’s the bottleneck effect)
Suppose you have a population of tree frogs, in which the favored homozygous dominant
genotype produces an all green color, the heterozygous genotype makes a green
and black spotted color. Describe an instance in which the favored genotype would change.
What causes this change? What is it’s affect on the gene pool of the population? What are the
advantages of having a favored phenotype?
A factory/natural disaster/tree disease could occur that causes a black discoloration
on the leaves of the tree. The would cause the heterozygous genotype to be favored
because it would make the frog be able to hide of the leaves from predators better
and the all green frog would be easier seen. This would cause the heterozygous
frogs to be more likely to survive, reproduce, and pass on their favorable genes
which would eventually alter the gene pool, as the other frogs would die. The
Heterozygous trait would also survival from predators.
LO 2.27 The student is able to connect differences in the environment with the evolution of homeostatic mechanisms. [See SP
7.1]
SP 7.1 The student can connect phenomena and models across spatial and temporal scales.
Explanation: In fish for example, that inhabit different aquatic environments that vary in salinity such as in the ocean or a
freshwater lake, must use the process of osmoregulation to achieve homeostasis. This process is known as a homeostatic
mechanism because it helps ensure the homeostasis of the fluids in the fish. In a freshwater lake environment fish must work
to retain their desired salinity by secreting a large amount of urine and absorbing salt through specialized cells in the gills.
These specialized epithelial cells located in the gills hydrolyze ATP and use the released energy to pump Na + and Cl- contained
in the water passing over the gills into the bloodstream. While present in freshwater environment osmosis causes the fish to
absorb water at an increased rate due to the greater salinity of the fish versus the surrounding aquatic environment. In a
saltwater environment the fish work to retain their desired salinity by excreting salt from specialized cells in their gills and
producing little urine to conserve fluids in their body and by constantly drinking seawater that is filtered by the kidneys and
gills. The specialized epithelial cells located in the gills hydrolyze ATP and use the released energy to pump Na+ and Cl- against
their concentration gradient and out of the bloodstream. While present in saltwater environments osmosis causes the fish to
lose water due to the greater salinity of the surrounding environment versus the salinity of the fish.
MC. Question
Which of the following specific homeostatic mechanisms is the most important pertaining to an environment where it is likely
for an organism to come into contact with multiple dangerous pathogens?
a) Thermoregulation- the ability of the hypothalamus to adjust the bodies temperature to a desired range to fight off the
spread of pathogens will ensure the organisms survival.
b) Immune Response- macrophages along with B-cells and T-cells of varying specialties work to activate the innate and
acquired immune response to eliminate and store information from potentially hazardous pathogens.
c) Chemical Regulation- controlled by the endocrine system and a complex web of feedback loops that help to maintain
chemical balances to promote normal bodily functions.
d) Nervous System- tasked with the control of most regulatory mechanisms in the body through the autonomous and
somatic systems.
FRQ
The classic example of the homeostatic mechanism of osmoregulation in both sea and freshwater is salmon during their
annual migration and mating. These aquatic environments vary greatly in salinity but through this process these fish are able
to transition to different aquatic environments. Using the diagram provided:
a) Explain the salinity concentration relative to the salmons aquatic environment including both saltwater and freshwater
using terms such as isotonic, hypertonic, and hypotonic.
b) Briefly describe the exchange of H2O and other molecules, mainly Na+ and Cl- in pertaining to the gain and loss of water
and nutrients in the different environments due to osmosis.
c) Another important homeostatic mechanism is thermoregulation. Define and give an example of how this works in
mammals.
Answer Key-LO 2.27
Which of the following specific homeostatic mechanisms is the most important pertaining to an environment where it is likely for an organism to come into
contact with multiple dangerous pathogens?
a) Thermoregulation- the ability of the hypothalamus to adjust the bodies temperature to a desired range to fight off the spread of pathogens will ensure
the organisms survival.
b) Immune Response- macrophages along with B-cells and T-cells of varying specialties work to activate the innate and acquired immune response to
eliminate and store information from potentially hazardous pathogens.
c) Chemical Regulation- controlled by the endocrine system and a complex web of feedback loops that help to maintain chemical balances to promote
normal bodily functions.
d) Nervous System- tasked with the control of most regulatory mechanisms in the body through the autonomous and somatic systems.
FRQ
The classic example of the homeostatic mechanism of osmoregulation in both sea and freshwater is salmon during their annual migration and mating. These
aquatic environments vary greatly in salinity but through this process these fish are able to transition to different aquatic environments. Using the diagram
provided:
a) Explain the salinity concentration relative to the salmons aquatic environment including both saltwater and freshwater using terms such as isotonic,
hypertonic, and hypotonic.
b) Briefly describe the exchange of H2O and other molecules, mainly Na + and Cl- in pertaining to the gain and loss of water and nutrients in the different
environments due to osmosis.
c) Following the discovery that salmon have specialized gills that contain pumps for Na and Cl- why must they delay their journey in brackish water for days
before continuing the transition from saltwater to freshwater?
a) In fresh water a salmon is considered hypertonic in nutrient concentration (Na + & Cl-) to the hypotonic freshwater.
In salt water a salmon is considered hypotonic in nutrient concentration (Na + & Cl-) to the hypertonic salt water.
b) In fresh water Salmon would absorb water via osmosis due to being surrounded by a hypotonic solution and would lose concentrations of Na+ and Clwithout osmoregulation.
In Salt water Salmon would lose water via osmosis due to being surrounded by a hypertonic solution and would gain a high concentration of Na+ and Clwithout osmoregulation.
c) Thermoregulation is the maintenance of an organisms internal body temperature within a tolerable range. An example of thermoregulation is mammals
is sweat.
LO 2.40: The student is able to connect concepts in and across domain(s) to predict how environmental factors affect responses
to information and change behavior.
SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring
understandings and/or big ideas.
Explanation: An example of how environmental factors affect behavior is imprinting. This is an example of a biotic factor
affecting an animal’s behavior. If a baby animal’s mother is lost for some reason during the critical period and another
organism comes into the baby’s life, it is going to think that the new organism is its’ mother and copy its’ actions. Seed
germination is also an example. Seeds will stay dormant until environmental conditions are ideal. Certain seeds are triggered
by different things such as heavy rainfall, intense heat, or cold weather. They won’t germinate, or sprout, until these
conditions are met. At this point, the hormone gibberellin is released and this starts the process of the growth of an embryo
into a seedling. One last example is photoperiodism. This is a plant’s physiological response to the length of day and night. A
very important response during the photoperiod due to this environmental condition is flowering in some plants.
Multiple Choice Question: What were the results of the 1913 Boysen-Jensen experiment?
A) They discovered what part of a coleoptile senses light.
B) They used an agar block to determine what side of plant got longer causing it to bend
towards the light.
C) They discovered that a light-activated mobile chemical was responsible for causing the
coleoptile to bend towards the light.
D) They discovered the first plant hormone named Auxin.
Learning Log/FRQ-style Question: Answer the following questions
about environmental factors affecting plants.
a) What is the effect of temporal barriers on the maturation of plants?
b) Describe specifically what happens in autumn as the weather gets colder
and there is less daylight.
c) Define phototropism, gravitropism, and thigmotropism.
ANSWER KEY LO 2.40
Multiple Choice Question: What were the results of the 1913 Boysen-Jensen experiment?
A) They discovered what part of a coleoptile senses light.
B) They used an agar block to determine what side of plant got longer causing it to bend towards the light.
C) They discovered that a light-activated mobile chemical was responsible for causing the
coleoptile to bend towards the light.
D) They discovered the first plant hormone named Auxin.
FRQ/LL Question: Answer the following questions about environmental factors affecting plants.
a)
What is the effect of temporal barriers on the maturation of plants?
Temporal barriers prevent self-fertilization. This happens when stamens and carpels within the
same plant mature at different times due to temperature.
b) Describe specifically what happens in autumn as the weather gets colder and there is less daylight.
In the autumn, different pigments like yellow and orange carotenoids are made. Chlorophyll is
no longer made. Leaves eventually fall off because aging leaves produce less auxin so the
abscission layer is more sensitive to ethylene. The weight of the leaf causes it to fall because
the abscission layer has thin walls.
c) Define phototropism, gravitropism, and thigmotropism.
Phototropism: The orientation of a plant or other organism in response to light, either toward
the source of light or away from it
Gravitropism: A turning or growth movement by a plant or fungus in response to gravity
Thigmotropism: A movement in which a plant moves or grows in response to touch or contact
stimuli
LO 3.35:The student is able to create representations that depict how cell-to-cell communication occurs by direct contact or from a distance
through chemical signaling.
SP 1.1:Students should be able to draw pictures that represent the particles we cannot observe but that match the accepted models for various
phenomena, such as ionic solids vs. metallic solids.
Explanation: The student must be able to draw diagrams or models representing the process of chemical signaling between cells. This refers
to the ability of a student to depict signaling resulting from direct contact, such as exchange of organic molecules through plasmodesmata.
An example of long distance signaling is Endocrine signaling using the blood stream. Endocrine signaling has two different processes of
reception within the receptor target cell. Steroid hormone reception involves intracellular receptors due to the non-polar properties of steroids
that can pass through the plasma membrane. Protein hormones are polar and bond to membrane-bound receptors due to their polar properties
and inability to pass through the membrane. Paracrine Signaling involves the depolarization of the plasma membrane of the synaptic terminal
followed by the opening of voltage-gated ions. The influx of Ca2+ ions causes synaptic vesicles to fuse with the membrane and triggers the
release of neurotransmitters into the synapse. The neurotransmitters then bind to the receptor of the ligand-gated ion channels of the postsynaptic membrane opening the channels allowing the neurotransmitter to enter the postsynaptic cell. An example of short distance chemical
signaling would be a neuron releasing neurotransmitters into the synapse between its axon terminals and the dendrite of the following
neuron. By depicting these signal pathways, one can gain a better understanding of these unseen processes.
Multiple Choice Question:
Which of the following models depicts Endocrine signaling?
A)
B)
C)
D)
Free Response Question:
Cells communicate with one another through many different methods including the Paracrine and Endocrine Systems.
Explain one of these processes of cell-to-cell signaling. Provide an example of the chosen type of signal and describe the
signal’s function. Draw and label an example of this process.
Answer Key L.O. 3.35
Free Response Question:
Cells communicate with one another through many different methods including the Paracrine and
Endocrine Systems. Explain one of these processes of cell-to-cell signaling. Provide an example of the
chosen type of signal and describe the signal’s function. Draw and label an example of this process.
Endocrine signaling is long-distance signaling via the circulatory
system. A cell uses a chemical, called a hormone, to send a stimulus or
message throughout the body. The hormone travels from either the
hypothalamus or an endocrine gland to its target cell. Once this
hormone reaches the target cell, it acts as a ligand and binds to a G
protein linked receptor or another receptor protein embedded in the
cell membrane. Once the ligand is bound, a transduction pathway
occurs sending the signal to the center of the cell to trigger the cellular
response. An example of this type of signaling would be insulin being
released by the pancreas and traveling through the blood stream to
the target cell. Insulin is an important hormone used to stimulate
growth and digestion of sugars.
Example Drawing
Learning Objective 3.37: The student is able to justify claims based on scientific evidence that changes in signal
transduction pathways can alter cellular response.
S.P 6.1: The students can justify claims with evidence.
Explanation: As blood glucose levels rise after eating a meal, non-diabetics release insulin. Insulin is a ligand that signals
cells in the liver to take up glucose from the blood, and this causes the blood sugar to return to normal. In type I diabetes, a
person’s blood sugar remains high and they do not produce insulin. In type II diabetes, insulin is released in response to high
levels of glucose, but the cells do not receive the signal. When Insulin binds to the cell's receptor, it will result in negative
feedback by limiting or stopping some other actions in the cell. It inhibits the release and production of glucose from the
cells which is an important part in reducing the glucose blood level. Insulin will also inhibit the breakdown of glycogen into
glucose by inhibiting the expression of the enzymes that catalyzes the degradation of glycogen. An example of this is
slowing or stopping the intake of glucose after the pathway has been activated. Negative feedback is shown in the insulin
signal transduction pathway by constricting the phosphorylation of the insulin-stimulated tyrosine. The dephosphorylation
of the insulin receptor slows the intake of the glucose from the blood by not allowing the other proteins in the insulin
transduction pathway to be activated and consequently not do their job of transferring the signal to the other proteins in
the pathway.
M.C Question: In signal transduction pathways, what is
the final step in activating the cellular response?
A) There is a phosphorylation cascade that activates
protein kinases for activation.
B) A phosphate group is added to a protein to trigger the
cellular response.
C) An enzyme is activated in response to a hormone
binding with a protein receptor.
D) There is a change in gene expression.
FRQ-Style Question: In signal transduction, what specific
role would a G protein-linked receptor take on in
triggering a cellular response? Does the structure of this
site change? If so, how?
ANSWER KEY – LO 3.37
In signal transduction pathways, what is the final step in activating the cellular response?
A) There is a phosphorylation cascade that activates protein kinases for activation.
B) A phosphate group is added to a protein to trigger the cellular response.
C) An enzyme is activated in response to a hormone binding with a protein receptor.
D) Genes carry out the rest of the process.
FRQ-Style Question: In signal transduction, what specific role would a G protein-linked
receptor take on in triggering a cellular response? Does the structure of this site
change? If so, how?
A G protein-linked receptor is a receptor in the plasma membrane that works with the help of
a protein, the G protein of course. Many different signal molecules such as hormones and
neurotransmitters use a G protein-linked receptor; however, their binding sites all differ. G
protein-linked receptors have remarkably similar structures, and they are used widely in
embryonic development and sensory reception. These receptors aid in the first process of
signal transduction because they receive the different signal molecules coming from outside
of the cell. The structures of these receptors only change after an appropriate signal molecule
is attached to the extracellular side of the receptor because the receptor is then activated
and binds to an inactive G protein on the cytoplasmic side; that changes the structure of the
receptor.
LO 2.14: The student is able to use representations and models to describe differences in
prokaryotic and eukaryotic cells
SP 1.4: The student can use representations and models to analyze situations or solve
problems
and
quantitatively
LO
2.14 focusesqualitatively
on the differences
of prokaryotes
and eukaryotes. Just by looking at the cell you can tell that they are two
different types of cells yet they are also similar. You can tell that the eukaryote is more advanced and complex than the
prokaryote because it contains more diverse organelles for example it contains mitochondria and endoplasmic reticulum.
Eukaryotes are also much greater in size than prokaryotes which is important because the logistics of carrying out cellular
metabolism sets limits on cell size. Although the eukaryote has more organelles they share common ones such as the DNA,
ribosomes, and a cell membrane. While both cells have DNA a prokaryote has a circular ring shape DNA and eukaryote have a
linear shape DNA. It is known that the prokaryote came before the eukaryote and actually it is believed that the eukaryote
evolved form the prokaryote. The cell theory states that every cell is formed from a pre- existing cell. When prokaryotes' DNA is
translated (mRNA) it becomes a transfer RNA (tRNA) and mutates more commonly because it does not have an operon that
"proofreads" the mutations that happens. In eukaryotes the nucleus contains operons so when it is transcribed it will have less
mutations. Eukaryotes are known to use energy because of their mitochondria while prokaryotes use multiple ways to produce
energy by being anaerobic or aerobic they do this by oxidation of inorganic compounds or respiration to make energy.
Multiple Choice
What is the most likely reason why prokaryotes evolved from having a nucleoid ( free floating DNA) to a nucleus?
A) It blocks out other viruses from trying to get to the DNA
B) It slows down the rate of transcription so it can check mutations and more organized so it can go straight to the ribosomes
C) To make it stop bumping into other organelles which may mess up the process of transcription
D) It is more important than the other organelles so it gets its own "bubble"
FRQ
A) Explain why it is believed that prokaryotes came before eukaryotes
B) Prokaryotes and Eukaryotes have a couple of organelles in common they are a bit different. List two organelles and explain
how they changed.
Answer Key LO 2.14
• Multiple Choice: B
–
–
–
–
Answer choice A is wrong because the nucleus does not prevent viruses from getting to the DNA
Answer choice B is correct because the nucleus is right beside the ribosomes and he
endoplasmic reticulum. It also prevents mutations to occur less and slowing down the process
of transcription lets the cell live longer
Answer choice C is wrong because a prokaryotes DNA is circular and there aren't many
organelles it could bump into other than the ribosomes.
Answer choice D is wrong because it does not get its own "bubble" just because its important.
The other organelles are just important and the cell couldn't function as a whole without all the
organelles together
FRQ Answer
A) 3 points for either saying it is smaller than a eukaryote or saying a eukaryote has more complex
organelles
2 points for saying they share common organelles
B) 1 point each for naming a common organelle in prokaryotes and eukaryotes (DNA, Ribosomes,
Cell
membrane)
3 points for naming how they evolved from prokaryotes to eukaryotes (DNA became linear and
enclosed in a nucleus, Ribosomes are attached to endoplasmic reticulum, Cell membrane has
created new and various channels)
LO 2.13: The student is able to explain how internal membranes and organelles contribute to cell function.
SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices.
Explanation: Lysosomes are cellular organelles that contain enzymes responsible for breaking down cellular material. They play a part in
digestion and waste removal. It uses the enzymes in order to digest food particles, excess organelles and engulfed viruses or bacteria.
They play a crucial role in breaking down dead parts of the cell and removing it. The membranes in the lysosomes are important because
they contain the dangerous enzymes and don’t allow them to leak out into the rest of the cell. The mitochondria breaks down nutrients
and converts it into energy in the form of ATP. It is named the “power house” of the cell because without it the cell would not be able to
produce energy to function. It is found in most Eukaryotic cells. It is also involved in other cellular activities such as cell differentiation and
signaling. This is the site of aerobic respiration. It allows for glycolysis, the krebs cycle, and oxidative phosphorylation. This will require
oxygen. The mitochondria is composed of the outer membrane and inner mitochondrial membrane. The inner mitochondrial membrane
has a folded structure and is known as cristae. These inner membrane help to minimize competing interactions as well as increase surface
area which has the affect of increasing the amount of ATP produced. This gives more room for reactions to occur. Generally with archaea
and bacteria they are lacking in internal membranes and have membrane bound organelles. This is because they need to be more
resistant.
M.C. Question: Which of the following statements is true concerning the
difference between the Smooth ER and the rough ER?
A) The rough ER is more tubular while the smooth ER is ribosome studded
B) The rough ER detoxifies many chemicals turning them into water soluble
products while the smooth ER carries out translation
C) The smooth ER’s lumen is where glycoprotein's are formed while the
rough ER releases calcium ions to control muscle contraction.
D) The smooth ER manufactures lipids while the rough ER assembles
proteins and transports them
Learning Log/ FRQ-style Question: The mitochondria is composed
of the inner and outer mitochondrial membrane. Each play its own
role in the functioning of the cell. How does the inner mitochondrial
membrane play a role in the production of ATP to supply energy for
cellular functioning?
ANSWER KEY – LO 2.13
Which of the following statements is true concerning the difference between the Smooth ER and the rough ER?
A) The rough ER is more tubular while the smooth ER is ribosome studded
B) The rough ER detoxifies many chemicals turning them into water soluble products while the smooth ER carries out translation
C) The smooth ER’s lumen is where glycoprotein's are formed while the rough ER releases calcium ions to control muscle contraction.
D) The smooth ER manufactures lipids while the rough ER assembles proteins and transports them
The mitochondria is composed of the inner and outer
mitochondrial membrane. Each play its own role in the
functioning of the cell. How does the inner mitochondrial
membrane play a role in the production of ATP to supply
energy for cellular functioning?\
The inner membrane contains many proteins used in
the electron transport chain and ATP synthesis. The
inner membrane surrounds the matrix in which the
citric acid cycle is responsible for creating the
electrons which travel from one protein complex onto
the next one. At the end of the ETC the final electron
acceptor is oxygen which binds to form water. The
ETC is producing ATP at the same time. In the ETC,
the protein complexes involved push protons in the
matrix into the inner membrane space. All ETC
proteins are located in the inner mitochondrial
membrane. Thus a concentration gradient of protons
is formed. ATP synthase then uses the concentration
gradient to synthesize ATP. The ATP synthase enzyme
is located in the inner mitochondrial membrane.
LO 1.26 The student is able to evaluate given data sets that illustrate evolution as an ongoing process.
SP 5.3 Students should also be able to evaluate the degree to which a set of evidence can address a scientific question, such as evaluating the
degree to which a particular set of observations indicates that a process is chemical versus physical, or indicates that a process is driven by
entropy, enthalpy, or both.
Explanation: Evolution is a concept best defined as a combination of natural selection, reproduction of the fittest, competition, and genetic
changes within a species. Charles Darwin was the first to uncover “descent with modification” when he observed a population of finches in the
Galapagos Islands. The finches inhabited islands, and due to allopatric speciation, each population began to form their own distinct traits.
Darwin concluded that, due to evolution (natural selection), variability among individual organisms in a population or speciation can occur as a
population of organisms adapts to their environment. Evolution also occurs as a result of chemical resistance. For example, colonies of bacteria
that contain antibiotic resistance genes will survive when the bacteria is exposed to that certain antibiotic. Overtime, these resistant bacteria
will multiply, forming an increasing number of colonies that are resistant the antibiotic. The number of colonies can be recorded to form a data
set that illustrates evolution as an ongoing process. The colonies that are not resistant will begin to disappear due to evolution’s reproduction
of the fittest. Evolution is also seen when homologous structures, such as limbs, are displayed next to each other and prove that many species
share common ancestors.
Multiple Choice Question
Which of the following statements is supported by the given set of data?
Antibiotic added
20 minutes
40 minutes
60 minutes
80 minutes
Antibiotic resistant colonies
40
80
160
320
640
Non-Antibiotic resistant colonies
100000
50000
25000
12500
6250
A)
B)
C)
D)
Allopatric speciation is occurring within the two different types of bacteria as one increases and the other decreases.
The formation of homologous bacteria structures is a result of the introduction of the antibiotic.
Reproduction of the fittest is shown as the antibiotic resistant colonies multiply and the non-antibiotic resistant colonies do not.
Darwin would suggest that the two groups of bacteria are competing for more colonies and the antibiotic resistant bacteria is winning.
Free Response Question
Evolution is a process that occurs in all living organisms.
a) Identify and describe two factors that lead to evolution.
b) Give a eukaryotic example that describes evolution as a structure
or process.
c) Lamarck believed that evolution occurred based on “use and
disuse” of an organism's structures. Explain why this theory can be
seen as accurate today.
ANSWER KEY-LO 1.26
Which of the following statements is supported by the given set of data?
A) Allopatric speciation is occurring within the two different types of bacteria as one increases and the other
decreases.
B) The formation of homologous bacteria structures is a result of the introduction of the antibiotic.
C) Reproduction of the fittest is shown as the antibiotic resistant colonies multiply and the non-antibiotic
resistant colonies do not.
D) Darwin would suggest that the two groups of bacteria are competing for more colonies and the antibiotic
resistant bacteria is winning.
Evolution is a process that occurs in all living organisms.
a) Identify and describe two factors that lead to evolution.
b) Explain a eukaryotic example that describes evolution as a structure or process.
c) Lamarck believed that evolution occurred based on “use and disuse” of an organism's structures. Explain why
this theory can be seen as accurate today.
a)
b)
c)
Natural selection is the process in which organisms better adapted to their environment tend to survive and
produce more offspring. Genetic changes can occur in a species that are beneficial for its survival, and the
mutated species will pass the trait onto its offspring.
Homologous structures are similar structures with different functions which show signs of evolution from a
common ancestor. A eukaryotic example would be the limbs of mammals. The wings of birds contain the
same structure as the arms of humans, yet their function is to enable them to fly. The human arm contains a
similar structure, suggesting a common ancestor, yet it is physically impossible for humans to fly.
Lamarck believed in the inheritance of acquired characteristics, such as the length of a giraffe’s neck evolving
based on how far they had to reach for food. This theory was proven wrong by Darwin, but it was later
discovered that it still holds true in epigenetics. Methylated genes can be inherited by an organism’s
offspring.
Source for picture on first slide: http://www.bio.miami.edu/dana/pix/homologous_forelimbs.jpg
LO 3.23: The student can use representations to describe mechanisms of the regulation of gene expression
SP 1.4: The student can use representations and models to analyze situations or solve problems qualitatively or
quantitatively.
•
Regulation of gene expression can occur on three different levels. On the DNA level, CH3 methyl groups cap off the DNA,
turning replication off. This is called DNA methylation. On the contrary, histone acetylation unwinds DNA for easier
transcription. Also on the DNA level, your patterns of DNA methylation and histone acetylation are inherited from parents in
epigenetic inheritance. Next you have the RNA level. On the RNA level, activator proteins bind to the distal control elements on
the DNA. Next, a DNA bending protein brings the bound activators closer to the promoter. The activators bind to certain general
transcription factors, helping them form an active transcription initiation complex on the promoter. This helps with the activation
of transcription. In dealing with RNA processing, mRNA degradation is done by miRNA and siRNA in a process called RNAi. A
single strand mRNA folds and an enzyme called Dicer moves along, cutting into shorter pieces. Then one stand of short doublestranded RNA is degraded; the other strand (miRNA) associates with complex proteins. Then the bound miRNA can base-pair with
any target mRNA than contains the complementary sequence. The miRNA-protein can prevent gene expression either by
degrading the target mRNA or blocking its translation. On the protein level, it is regulated in a process called protein degradation.
First, multiple ubiquitin molecules are attached to a protein by enzymes in the cytosol. Next, the ubiquitin-tagged protein is
recognized by a proteasome which unfolds the protein and sequesters it within a central cavity. Enzymatic components of the
proteasome cut the protein into small peptides which can be further degraded by the other enzymes in the cytosol. All of these
mechanisms are used to regulate the amount of DNA, RNA, and protein.
M.C. Question: Which of these processes occurs on the RNA level?
•
A) DNA methylation
•
B) Histone acetylation
•
C) Alternative splicing
•
D)Protein degradation
FRQ-style Question: Sally’s cat Tom has a deficiency of an enzyme called Dicer
which is used in mRNA degradation.
Explain the importance of this process and the effect of having a deficiency of this enzyme.
ANSWER KEY- LO 3.23
Which of these processes occurs on the RNA level?
•
A) DNA methylation
•
B) Histone acetylation
•
C) Alternative splicing
•
D)Protein degradation
Sally’s cat Tom has a deficiency of an enzyme called Dicer which is used in mRNA degradation. Explain the importance of this
process and the effect of having a deficiency of this enzyme.
Dicer is used in a process called mRNA degradation which is used to control the amount of RNA by using a dicer to degrade
the mRNA. Without the dicer, the single stand of mRNA will never be cut into shorter pieces that will be degraded. The
other strand, which is miRNA associates with other complex proteins. The bound miRNA can base pair with any target
mRNA that contains the complementary sequence. This miRNA-protein complex prevents gene expression either by
degrading the target mRNA or blocking its translation. This process is important because without it the regulation of RNA
will never occur, which will lead to the build up of RNA. Because this process is so important in RNA regulation and since
the enzyme dicer plays such an integral role in this process, it will cause many complications with RNA build-up.
LO 2.20: The student is able to justify that positive feedback mechanisms amplify
responses in organisms.
SP 6.1: The student can justify claims with evidence
Explanation: Positive feedback is when a rather small stimulus reaches a system and the response of said system consists of releasing
more of the original stimulus which will, in turn, activate more systems; positive feedback is representative of exponential growth.
For example, during labor, the endocrine systems of women release oxytocin which causes contractions. Those contractions cause
more oxytocin to be released which, once again, increase contractions. So there's a large increase in the original stimulus. Putting it in
simpler terms, it's like watching the growth of a viral video. One person sees it then shows it to their friends. Those friends then show
it to their friends and the pattern continues. It is because positive feedback mechanisms do this that they do indeed amplify responses
in organisms.
Multiple Choice Question: Which of the following
would be considered a characteristic of positive
feedback mechanisms?
(A.) They are homeostatic.
(B.) They are commonly found in the nature.
(C.) They represent linear growth.
(D.) Only A and B are correct.
FRQ: Consider positive feedback mechanisms.
Provide two examples of positive feedback
mechanisms. One should show a positive effect of
positive feedback mechanisms and the other should
show a negative effect of positive feedback
mechanisms.
Multiple Choice Question: Which of the following would be considered a characteristic of
positive feedback mechanisms?
(A.) They are homeostatic.
(B.) Commonly found in the nature.
(C.) Represent linear growth.
(D.) Only A and B are correct.
FRQ: Consider positive feedback mechanisms.
Provide two examples of positive feedback
mechanisms. One should show a positive effect of
positive feedback mechanisms and the other should
show a negative effect of positive feedback
mechanisms.
Answer Key
– LO 2.20
NOTE: There are multiple possible answers for this.
An example that shows a positive effect of positive
feedback mechanisms would be wound healing.
When a person is injured, platelets in the blood
soon stick to the injured area and release chemical
messengers which cause more platelets to come and
stick to the injured area(and so on). If it weren't for
this positive feedback mechanism, blood clotting
would not occur and it would be easy to lose large
amounts of blood from cuts.
An example that shows a negative effect of positive
feedback mechanisms would be the development of
a fever in the body to fight an infection. The human
LO 3.8: The student can describe the events that occur in the cell cycle
SP 1.2: The student can describe representations and models of natural or man-made phenomena and
systems in the domain
Explanation: The cell cycle has 3 stages (interphase, mitosis, and cytokinesis) and these are regulated by
checkpoints. In interphase there are 3 phases which are growth, synthesis of DNA, and preparation for mitosis.
Cyclin and cyclin-dependent kinases are what control the cell cycle. Cells can enter stages where they no
longer divide, but later reenter the cell cycle. Non-dividing cells can exit the cell cycle and can also hold or stop
at certain stage in the cell cycle. Mitosis happens after DNA is replicated and the end product after cytokinesis
is two daughter cells that are identical to each other and the parent cell. The phases of mitosis are prophase,
metaphase, anaphase, and telophase. Mitosis plays a role in cell growth, repair and asexual reproduction. For
sexual reproduction there is meiosis. Meiosis creates genetic diversity. This is because during meiosis crossing
over occurs where homologous chromatids exchange genetic material . Homologous chromosomes are paired,
one from the maternal parent and another from the paternal. Each gamete receives one haploid (n) set of
chromosomes because of meiosis.
M.C. Question: Which of the following statements about the cell cycle is false?
A) If a cell specializes it often enters a stage of
no longer dividing.
B) Interphase consists of the G1, S, and G2
phases.
C) Meiosis like mitosis creates two identical
cells.
D) Cells can be held or stop are certain points
in the cell cycle for certain amounts of time.
FRQ Question: Cyclin helps control the cell cycle expalin what
cyclin does in the cell cycle and what would happen if cyclin
was not present in the cell cycle.
ANSWER KEY—LO 3.8
Which of the following statements about the cell cycle is false?
A)If a cell specializes it often enters a stage of no longer dividing.
B) Interphase consists of the G1, S, and G2 phases.
C) Meiosis like mitosis creates two identical cells.
D) Cells can be held or stop are certain points in the cell cycle for certain amounts of time.
Cyclin helps control the cell cycle explain what cyclin does in the cell cycle and what would happen if
cyclin was not present in the cell cycle.
Cyclin is attached to cyclin-dependent kinases (Cdks). Cdks are inactive until they attach to the
cyclin. Cdk levels rise and falls with the concentration of cyclin. Cdks are what give the “go-ahead”
signals at the G1 and G2 checkpoints. Without cyclin in the cell cycle the cell would be stuck in the
G1 phase because Cdks would have nothing to attach to so they would never be become active and
because of this would not be able to signal at checkpoints.
Learning Objective 1.6 - The student is able to use data from mathematical models based on the Hardy-Weinberg equilibrium to
analyze genetic drift and the effect of selection in the evolution of specific populations.
SP 1.4 - The student is able to evaluate data-based evidence that describes evolutionary changes in the genetic makeup of a population over time.
SP 2.1 - The student is able to explain how biological systems use free energy based on empirical data that all organisms require constant energy
input to maintain organization, to grow, and to reproduce.
The Hardy-Weinberg Equilibrium mathematical equation (shown below) is an example of using math to calculate genetic variation
of a population and numerically see the evolutionary changes over time as organisms reproduce. It is used to determine that the
allelic frequency of a small population will change much faster than that of a large population; this is also known as genetic drift.
•
•
•
•
•
p = Dominant allele
q = Recessive allele
P^2 = Dominant homozygous
q^2 = Recessive homozygous
2pq = Heterozygous
Microevolution will occur if these 5 requirements for
population are not met:
1.
2.
3.
4.
5.
Large Population
Isolated population
Random Mating
No Natural Selection
No Mutations
Free Response
A common example of genetic drift involves the population of
Amish in Pennsylvania. Since they are isolated, and are a relatively
small population, they have evolved at a different rate than people
who live in Germany where the original, much larger population is
located. The gene flow within their community is close to being
completely isolated due to the fact that the Amish mate within a
small gene pool. This provides less variation, which can eventually
harm a population. If one family member had a mutation and
mated with another, an the child produced that mutation, then the
colony would soon show multiple cases of that mutation, since it is
now a fixed allele.
Math Practice
a) Identify two different mechanisms of
genetic change that cause
microevolution; explain how each
effects the population.
b) Why is genetic variation so important?
A population of 1612 stray dogs
are roaming Winston-Salem.
There are 1469 Black Labs (AA),
5 White Labs (aa), and 138 Gray
Labs (Aa). What are the allelic
frequencies (p and q)?
Multiple Choice
The Hardy-Weinberg Theorem describes non-evolving populations.
Why will alleles and genotypes in a gene pool not remain constant?
a) Outside agents are always interfering c ) Random mating can’t be controlled
b) The small population does not
d) A and C
experience natural selection
ANSWER KEY FOR OBJECTIVE 1.6
Multiple Choice
Math Practice
Answer is A
Since the Hardy Weinberg Theorem describes
a non-evolving environment, the genes and
alleles must remain constant. However, we are
always evolving, meaning our gene pool will
continue to flow due to outside agents
interfering or mutating.
p = .95
q = .05
1469/ 1612 = .91129
P^2 = .91129
Free Response
138/1612 = .0856
2pq = .0856
5/1612 = .003101
q^2 = .003101
a) 1 - The Bottleneck effect changes the
population due to a disaster, which reduces
the population size so that the surviving
population is not a good representative of
the original. 2 - The Founder Effect is
genetic drift in a new colony, such as an
island, creating a different pattern of
evolution in a smaller population.
Square Root of p^2 is .95
.95 = p
a) Genetic variation within a population
provides for multiple traits to be made and
evolve through natural selection. Allelic
frequencies will change due to the
necessity of that trait to survive in the
environment.
This means that 95% of the alleles in the
stray dogs are dominant (p) while 5% of
alleles are recessive (q).
Square Root of q^2 is .05
.05 = q
LO 1.25: The student is able to describe a model that represents evolution within a population.
SP 1.2: The student can describe representations and models of natural or man-made
phenomena and systems in the domain
Explanation: There are many different mechanisms of evolution, including natural selection. Natural selection is when an
organism of a species has an adaptive advantage that carries over to the next generation of that species. There are different
modes of selection such as directional selection, the most common type, in which a population’s environment changes,
resulting in a shift in the overall makeup of the population favoring variants at one extreme of the distribution. A second
mode is disruptive selection, which occurs when conditions favor individuals on both extremes of a phenotypic range over
individuals with moderate phenotypes. A third mode is stabilizing selection, which acts against extreme phenotypes and
favors intermediate variants.
M.C. Question: Which of the following is stabilizing selection?
A) Average size of Black bears in Europe increasing with each
glacial period and decreasing during warmer interglacial periods
B) A population of birds which displays two distinctively different
sized beaks: small billed and large billed, and relatively
few intermediate bills
C) Early mortality for human babies is high at both weight
extremes, making intermediate babies more likely to survive
D) Peppered moths in rural England are very light and
peppered moths in industrial locations are very dark,
few intermediate colored moths were present
Learning Log/FRQ-Style Question: a population of birds with heritable variation in feather color from dark green to light
green migrates to a new habitat that has trees with darker green leaves than the previous habitat. Which colored feather
will be favored in the new habitat? Why? What mode of natural selection is this and why? If the habitat develops into more
forest with light green colored leaves as well as dark green leaves, what will most likely happen to the bird population and
why?
ANSWER KEY-LO 1.25
MC Answer: Which of the following is stabilizing selection?
A) Average size of Black bears in Europe increasing with each
glacial period and decreasing during warmer interglacial periods
B) A population of birds which displays two distinctively different
sized beaks: small billed and large billed, and relatively
few intermediate bills
C) Early mortality for human babies is high at both weight
extremes, making intermediate babies more likely to survive
D) Peppered moths in rural England are very light and
peppered moths in industrial locations are very dark,
few intermediate colored moths were present
Learning Log/FRQ-Style Question Answer: a population of birds with heritable variation in feather color from
dark green to light green migrates to a new habitat that has trees with darker green leaves than the previous
habitat. Which colored feather will be favored in the new habitat? Why? What mode of natural selection is
this and why? If the habitat develops into more forest with light green colored leaves as well as dark green
leaves, what will most likely happen to the bird population and why?
The birds with the dark green feathers are favored because the dark feathers provide more
camouflage from predators, allowing the dark green birds to survive and reproduce. This is directional
selection because there is a shift in the overall make up of the bird population, favoring the dark green
feathered variants. If the habitat develops into having both light green leaves and dark green leaves,
disruptive selection will occur, resulting in both extreme variants of the population to be favored and for
the intermediate phenotype not to be. This means that light green feathered birds and dark green
feathered birds will be more populous then intermediate green.
LO 1.9: The student is able to evaluate evidence provided by data from many scientific disciplines that
support biological evolution.
SP 5.3: The student can perform data analysis and evaluation of evidence.
Explanation: Evidence for biological evolution is provided through numerous scientific disciplines, including physical,
chemical, and biogeographical. Physical evidence of evolution includes homology, paleontology, and embryology. In
homology, scientists can study homologous structures, which are similarly structured appendages in different species that
signify descent from a common ancestor, and vestigial structures, which are structures that have marginal, if any,
importance to the organism but were significant structures in the organism’s ancestors. In paleontology, transitional fossils
that link modern organisms to ancients organisms can unveil descent from an ancestral species. In comparative embryology,
similarities in the embryo development of different species can additionally display descent from a common ancestor.
Chemical evolutionary evidence shows all life forms use the same “ATGC” code in their DNA and have similar protein
sequences which again indicates common ancestry. Similarities in two organisms’ DNA sequences can be compared using
the BLAST web database. For example, the database will show that the DNA sequence for a certain protein has a much
higher percentage of similarity between humans and chimpanzees than between humans and tapeworms because humans
and chimpanzees share a more recent common ancestor. Biogeographical evidence shows the geographic distribution of
species. Species that have recently descended from a common ancestor, and are therefore closely related, tend to live in the
same geographic region.
M.C. Question: Evolutionary relationships can be shown on anatomical, molecular, and geographical
levels. If you were studying two species that you know to be closely related, which of the following
would not be proof of their evolutionary relationship?
A.) Both species have similar vestigial organs.
B.) Both species occupy the same ecological niche in two distant regions.
C.) The embryos of both species develop pharyngeal pouches and post-anal tails.
D.) Both species have similar homologous structures in their forelimbs.
Learning Log/FRQ-style Question: Scientists have recently discovered a
new species that they believe is a close relative of the modern day
whale. However, some researchers have their doubts as to whether
the two species are actually related. What are four pieces of evidence
the scientists can use to support their claim, and how does this
evidence show the two species’ evolutionary relationship?
ANSWER KEY- LO 1.9
Evolutionary relationships can be shown on anatomical, molecular, and geographical levels. If you were
studying two species that you know to be closely related, which of the following would not be proof of their
evolutionary relationship?
A.) Both species have similar vestigial organs.
B.) Both species occupy the same ecological niche in two distant regions.
C.) The embryos of both species develop pharyngeal pouches and post-anal tails.
D.) Both species have similar homologous structures in their forelimbs.
Scientists have recently discovered a new species that they believe is a close relative of
the modern day whale. However, some researchers have their doubts as to whether
the two species are actually related. What are four pieces of evidence the scientists
can use to support their claim, and how does this evidence show the two species’
evolutionary relationship?
Scientists could demonstrate evolutionary relationship through proof of homologous
structures. If the forelimbs of the new species and the modern whale are constructed with
the same basic structural and skeletal elements, it would indicate that the two species share
a common ancestor. Scientists could also use molecular homologies to support their claim. If
samples from the same proteins are taken from each of the two species, scientists could
upload the DNA sequences onto the BLAST web database and determine the percentage
similarity between the sequences. The higher the percentage similarity, the more closely
related the species are as this indicates descent from a common ancestor. Evolutionary
relationship can additionally be supported through studying the two species embryos.
Anatomical similarities in the embryo development indicate the species share a common
ancestor. Scientists could also support their claim by showing that the two species tend to be
found living in the same geographic region as this is true of closely related species.
LO 3.36: The student is able to describe a model that expresses the key elements of signal transduction
pathways by which a signal is converted to a cellular response.
SP 1.5: The student can connect phenomena and models across spatial and temporal scales.
d) A ligand Gaited ion channel that opens and closes to allow or
block Ca2+ and Na+ ions when signal molecules bind as a ligand
Signal Transduction pathways allow for cells to receive chemical
to a specific protein.
messages from outside of the membrane. Chemical signals are
detected when a ligand binds to the receptor protein usually on the Learning log/ FRQ Style question:
surface of the cell, but not excluding intracellular receptors. Lipid
Why are signal transduction pathways considered to have an
soluble hormones penetrate the target cell and bind to Intracellular advantage over simpler systems? Explain. And provide at leat one
receptors normally located in the nucleus or cytoplasm within the
example
cell thus altering gene expressing through activating transcription.
When the signal and receptor bind this changes the tertiary structure
of the protein which then initiates a transduction of the signal.
External signals stimulate relay molecules which triggers a cellular
response. When specific signal molecules bind to membrane receptors
this creates a transduction pathway. The relay molecules or proteins
are phosphorylated (adding a phosphate group) by kinase ( enzyme)
in order to activate the protein. Tyrosine kinase receptors for example
activate other tyrosine kinases by phosphorylation until the final
protein is phosphorylated bringing about the cells response to that
particular signal. Secondary messengers can help to transfer
information after the receptor ligand complex has begun the signal
transduction pathway. IP3, cyclic AMP and Cyclic GMP are all
examples of second messengers.
M.C Question: Which of the following is not a direct example of a
signal transduction pathway?
a) A G Protein linked receptor binding and activating a specific G
protein
Ligand gaited ion Channels
b) Receptor Tyrosine Kinase triggering more than on e s signal
open and close when a signal
transduction pathway by phosphorylating relay proteins
molecule binds to the
c) Testosterone flowing through the blood stream binds to a signal
receptor protein
receptor on the surface of a cell.
Explanation:
Answer Key-LO 3.36
Which of the following is not a direct example of a signal transduction pathway?
A) A G Protein linked receptor binding and activating a specific G protein
B) Receptor Tyrosine Kinase triggering more than one signal transduction pathway by phosphorylating relay proteins
C) Testosterone flowing through the blood stream binds to a signal receptor on the surface of a cell.
D) A ligand Gaited ion channel that opens and closes to allow or block Ca2+ and Na+ ions when signal molecules bind as a ligand
to a specific protein
Why are signal transduction pathways considered to have an advantage over simpler systems? Explain and
provide at least one example.
Signal Transduction pathways have an advantage over more simple systems in which they are able to amplify a signal. Molecules
that transfer the signal to numerous other molecules in the next step of the transduction Pathway may result in a large number
of activated molecules towards the end of the cascade. Tyrosine Kinase receptors for example can trigger more than one signal
transduction pathway which will help regulate cell growth and reproduction. Tyrosine kinase can activate up to ten or more
various pathways and responses. A small number of outer cellular signals produce a large cellular response which will
Ultimately enable more regulation of enzymes as well as energy metabolism of specific cells.
LO 1.19: The student is able to create a phylogenetic tree or simple cladogram that correctly
represents evolutionary history and speciation from a provided data set.
SP 1.1: The student can create representations and models of natural or man-made phenomena
and systems in the domain.
Explanation: Cladograms and phylogenetic trees are graphical representations of the genetic
evolution between species. They show how closely species evolve from common ancestors.
Cladograms and phylogenetic trees are constantly changing and are based off of the biological
data used, new computational and mathematic ideas, and current and newly emerging
knowledge. They also illustrate speciation and visually represent the accumulation or loss of
specific traits over time through generations. These structures can be made by creating a map of
sorts of the development of traits between species over time. Information used to create
cladograms may include, but is not limited to: fossils, homologous structures, and, most
importantly, DNA. These factors can help determine how closely related species are.
M.C. Question: Which of the following relationships between species would best lead to the species being
closely located on a cladogram?
A. A butterfly and a spider, which are both insect-like
B. A small bird and a flying squirrel, which both have wing-like
homologous structures
C. A human and a dog, which are both mammals
D. A large sporangium and a bryophyte, which are both plants
FRQ Question: Create a cladogram that will correctly show the following evolutionary
development of traits of a certain animal: A, B, and D have wings; C and E have toes; B has
hair; A and D have 5 fingers. Then, give a written explanation of potential reasons for the
development/loss of the traits and explain why you placed them where you did on the cladogram.
Answer Key LO 1.19
M.C. Which of the following relationships between species would best lead to the species being
closely located on a cladogram?
A. A butterfly and a spider, which are both insect-like
B. A small bird and a flying squirrel, which both have wing-like
homologous structures
C. A human and a dog, which are both mammals
D. A large sporangium and a bryophyte, which are both plants
FRQ: Create a cladogram that will correctly show the following evolutionary development of
traits of a certain animal: A, B, and D have wings; C and E have toes; B has hair; A and D have 5
fingers. Then, give a written explanation of potential reasons for the development/loss of the
traits and explain why you placed them where you did on the cladogram.
Since A, B, and D have wings, whereas E and C have
[sample drawing]
toes, the two groups have separate branches on the
A
D
C
B Hair
E
5 fingers
Toes
Wings
cladogram. The two groups may have diverged long
ago due to allopatric speciation (some of the
organisms needed to fly more and some could walk
easier) or a gradual buildup of genetic mutations.
Only A and D have 5 fingers so that trait must have
evolved later on. This could have occurred because
the environment changed over time to one that
required more moving on the ground rather than
flying everywhere. B is the only organism with hair
so this trait must’ve developed on it’s own, most
likely due to a genetic mutation. Obviously the new
hair trait was not beneficial because it was dropped
after B.
Alaine Castillo – 2nd (LO 3.47)
LO 3.47: The student is able to create a visual representation of complex nervous systems to describe/explain how these systems
detect external and internal signals, transmit and integrate information, and produce responses.
SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain.
Explanation: In the Nervous System (brain,
spinal cord, network of neurons) - which is
separated into two main parts, Central
Nervous System and Peripheral Nervous
System - there are three general stages of
information processing: sensory input,
integration, and motor input. Sensors in the
PNS first detect any stimuli (such as the six
senses: touch, sound, hear, smell, taste,
light…) from the environment and any internal
conditions (such as blood pressure, muscle
tension…). These afferent (sensory) neurons
then carry this information to the brain and
spinal cord in the CNS to be analyzed and
interpreted by interneurons. Then the
efferent (motor) neurons take the information
out of the CNS and back to the PNS to our
muscles, producing a natural response or
reflex due to the stimuli. The touch of a
burning stove and the sudden movement
afterwards is an example of this, as well as
sitting in silence, hearing someone sneeze and
therefore turning the head toward the noise.
M.C. Question: What is most likely to occur if motor neurons were absent?
A) Stimuli will continue to be detected and will instead be transported by sensory neurons to be integrated
to produce a natural response.
B) There will be absolutely no processing of information in the body.
C) Any external stimuli can no longer be detected; thus, information processing cannot occur.
D) Stimuli will continue to be detected and integrated; however, control of muscle movement is lost.
Learning Log Question: Jake has recently been diagnosed with ALS (Amyotrophic Lateral Sclerosis), the
progressive degeneration of motor neurons., often leading to death in 2 to 5 years. What would be the result
of this in terms of his body? Provide characteristics and symptoms of the effect of the loss of neurons. Would
his nervous system still be able to process information to its entirety? Justify and explain.
Answer Key – LO 3.47
M.C. Question: What is most likely to occur if motor neurons were absent?
A) Stimuli will continue to be detected and will instead be transported by sensory neurons to be integrated
to produce a natural response.
B) There will be absolutely no processing of information in the body.
C) Any external stimuli can no longer be detected; thus, information processing cannot occur.
D) Stimuli will continue to be detected and integrated; however, control of muscle movement is lost.
Answer Key (cont.) – LO 3.47
Learning Log Question: Jacob has recently been diagnosed with ALS (Amyotrophic Lateral Sclerosis), the
progressive degeneration of motor neurons., often leading to death in 2 to 5 years. What would be the result
of this in terms of his body? Provide characteristics and symptoms of the effect of the loss of neurons. Would
his nervous system still be able to process information to its entirety? Justify and explain.
Because Jacob is progressively losing his motor neurons, he would later no longer be able to control muscle
movement. He would experience increasing weakness first in the limbs , progressing to the whole body and
other symptoms like cramping, twitching, atrophy as well as having trouble breathing and clearing secretions
(bladder and bowel disfunction). Although some show sensory deficits, the loss of motor neurons usually do
not have anything to do with sensory changes because it contains and uitilizes sensory neurons rather than
motor neurons; therefore, he would most likely still be able to detect external stimuli such as heat, sound, light,
etc. but would be unable to produce an automatic muscle movement reflex in response to the stimuli.
•
LO 4.6 The student is able to use representations and models to analyze situations qualitatively to describe how interactions
of subcellular structures, which possess specialized functions, provide essential functions.
•
SP 1.4 The student can use representations and models to analyze situations or solve problems qualitatively and
quantitatively.
•
Explanation: Subcellular structures must work together in order for the cell to carry out its specific function. The
arrangement of each subcellular structure coordinates with other structures so that their functions may interact and carry
out their purpose. For example, unlike most subcellular structures, ribosomes have no membrane. This enables them to
float freely in the cytoplasm, picking up tRNA from the nucleus and binding to amino acids to make protein chains. The Golgi
Apparatus has a polar charge, so that transport vesicles from the rough ER containing secretory proteins may bind to it’s cis
face, and these proteins are modified in the Golgi, then sent to other destinations in vesicles. The lysosome is also an
excellent example of the interaction of subcellular structures, as it’s enzymes and membrane are made by the rough ER and
processed by the Golgi. Digestion in the lysosome produces vital products such as amino acids, monomers and simple
sugars.
•
Multiple Choice Question: Which of the following statements concerning the interaction of peroxisomes with other
subcellular structures is false?
A. Peroxisomes use oxygen to break down fatty acids into smaller molecules, that are transported to the
mitochondria for
cellular respiration.
B. Peroxisomes reside within the endomembrane system.
C. Peroxisomes are enlarged by incorporating proteins from the cytosol.
D. In plant cells, the peroxisome is located in close proximity to chloroplasts.
•
Free Response Question: A cell’s cytoskeleton is an integral part of its composition. Describe the structure and function of
two components of the cytoskeleton, listing examples and explaining their interaction with other subcellular structures.
Answer Key – LO 4.6
•
for
•
Multiple Choice Question: Which of the following statements concerning the interaction of peroxisomes with other subcellular
structures is false?
A. Peroxisomes use oxygen to break down fatty acids into smaller molecules, that are transported to the mitochondria
cellular respiration.
B. Peroxisomes reside within the endomembrane system.
C. Peroxisomes are enlarged by incorporating proteins from the cytosol.
D. In plant cells, the peroxisome is located in close proximity to chloroplasts.
Free Response Question: A cell’s cytoskeleton is an integral part of its composition. Describe the structure and function of two
components of the cytoskeleton, listing examples and explaining their interaction with other subcellular structures.
The cytoskeleton is composed of microtubules, microfilaments and intermediate filaments. Microtubules grow out of
a centrosome and are hollow tubes made from tubulin, required for the maintenance of cell shape, cell motility, chromosome
movements in cell division, and organelle movements. Motor proteins move along microtubules; for example, microtubules guide
secretory vesicles from the Golgi to the plasma membrane. Microtubules are responsible for the locomotor appendages of the cilia
and flagella. These enable cell motility, or the movement of fluids over non-motile cells. For example, the ciliated windpipe sweeps
mucus containing trapped debris out of the lungs. Microfilaments are solid rods also known as actin filaments, because they are
built from actin, a globular protein. The functions of microfilaments include: maintaining the cell’s shape by bearing tension, using
myosin and actin to contract muscle cells, forming cleavage furrows to enable cell division, and performing cytoplasmic streaming
in large plant cells. In cytoplasmic streaming, actin-myosin interactions cause a circular flow of cytoplasm that speeds the
distribution of materials within the cell. Intermediate filaments are a diverse group of cytoskeletal elements made of keratin
proteins. They are more permanent than microfilaments & microtubules, and often remain present even after cell death, which
suggests that they reinforce the shape of a cell and organize the placement of its organelles. For example, the nucleus commonly
sits within a cage made of intermediate filaments.
LO 4.25: The student is able to use evidence to justify a claim that a variety of phenotypic responses to a single
environmental factor can result from different genotypes within the population.
SP 6.1: The student can justify claims with evidence.
Explanation: This objective has to do with genetic diversity, and how this diversity can affect the evolution of a
population. Genetic diversity is important, as species with high genetic diversity can better adapt to changes in the
environment than those with low genetic diversity. For example, genetically modified crops, or GMOs, are risky because
they lack genetic diversity. If there is a change in the environment that doesn’t favor the single genotype of the crop,
then they will all die. This can also occur in disease resistance in people: not all individuals are affected by an outbreak in
the same way because their genetic makeups are different. Different responses or phenotypes of some species can lead
to extinction while others thrive.
Multiple Choice Question: Two populations of rabbit live on an island when a new predator is introduced. Species 1 has
genotypes for many different colors of fur, while Species 2 only has the genotype for white fur. Which species is more
likely to be selected for?
a) Species 1 is more likely to be selected for because there is greater genetic
variation in the population.
b) Species 1 is more likely to be selected for because it is at Hardy-Weinberg
equilibrium.
c) Species 2 is more likely to be selected for because there is no gene flow in the
population, making the species closer to equilibrium.
d) Species 2 is more likely to be selected for because there is a greater chance of
microevolution.
Learning Log/FRQ-style Question: Suppose you have a population on an island and
a disaster hits, causing a small portion of the population to end up on a
neighboring deserted island.
a) Predict the result of this event in terms of the genetic variation of the
population. Explain your prediction.
b) If the population on the new island is 100 and 51 show the dominant
phenotype, predict how many individuals would be expected in each of the
three genotypes.
c) A disease breaks out on the island and the heterozygotes are selected for.
Explain this phenomenon. Include another example in your explanation.
Answer Key- LO 4.25
Multiple Choice Question: Two populations of rabbit live on an island when a new predator is introduced. Species 1 has
genotypes for many different colors of fur, while Species 2 only has the genotype for white fur. Which species is more likely
to be selected for?
a) Species 1 is more likely to be selected for because there is greater genetic variation in the population.
b) Species 1 is more likely to be selected for because it is at Hardy-Weinberg equilibrium.
c) Species 2 is more likely to be selected for because there is no gene flow in the population, making the species closer to
equilibrium.
Learning Log/FRQ-style Question: Suppose you have a population on an island and a disaster hits, causing a small portion
d) Species 2 is more likely to be selected for because there is a greater chance of microevolution.
of the population to end up on a neighboring deserted island.
a) Predict the result of this event in terms of the genetic variation of the population. Explain your prediction.
b) If the population on the new island is 100 and 51 show the dominant phenotype, predict how many individuals
would be expected in each of the three genotypes.
c) A disease breaks out on the island and the heterozygotes are selected for. Explain this phenomenon. Include another
example in your explanation.
a) Genetic variation would most likely decrease due to genetic drift. Genetic drift occurs when a gene pool of a small
population changes due to chance. In this case, the disaster occurred by chance, causing the more specific type of
genetic drift, the founder effect. The founder effect occurs when a new colony is established, leading to a decrease
in genetic variation. The new population is small and isolated, leading to decreased variability.
b) AA + Aa= 51 → .49 = aa= 𝒒𝟐
q = .7 → p = .3 → 2pq = .42
𝒑𝟐 = .09
p + q = .3 + .7 = 1
𝒑𝟐 + 2pq + 𝒒𝟐 = 1
aa= 49 AA= 9
Aa= 42
c) This phenomenon is the heterozygote advantage, in which the genotype Aa has the advantage over both the
homozygous dominant genotype and the homozygous recessive genotype, as the heterozygous phenotype is
between that of the dominant and recessive. For example, in Africa, the heterozygotes for sickle-cell anemia have
the heterozygote advantage for malaria. Those homozygous dominant for sickle-cell cannot get malaria, but can
die of sickle-cell anemia. Those homozygous recessive for sickle-cell can get malaria. However, the heterozygotes
for sickle-cell have red blood cells that are in between sickle and normal, preventing contraction of malaria and the