1st Review Project collection
LO 2.7: The student is able to explain how cell size and shape affect the overall rate of nutrient intake and the rate of
waste elimination.
SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific
practices
Explanation: Cells typically are small, even microscopic, to maximize their ability to take in nutrients and eliminate
waste. Aside from size, the shape and structure of a cell affects its functionality. The two types of cells, prokaryotic and
eukaryotic, are structurally disparate. The eukaryotic cells are usually bigger than the prokaryotic cells and they are
more sophisticated. Eukaryotic cells have internal membranes, which divide them into compartments. These
membranes are composed of enzymes which contribute to the cell’s metabolism. The prokaryotic cells function at a
very rudimentary level, expending just enough energy to sustain themselves and reproduce. The most efficient cells
have a higher ratio of surface area to volume. The surface area of each cell type’s plasma membrane must be large
enough to adequately exchange materials; smaller cells have a more favorable surface area to volume ratio for
exchange of materials with the environment. In general, smaller eukaryotic cells have a higher rate of nutrient intake
and waste elimination.
Multiple Choice Question: You are performing a lab experiment where you are examining
three cells. Cell A and Cell B each have a membrane bound nucleus and internal membranes.
The surface area to volume ratio of Cell A is larger than that of Cell B. Cell C appears to have
no true nucleus, and also lacks many of the membrane-enclosed organelles found in Cell A
and Cell C. Which of these cells would have a higher rate of nutrient intake?
A) Cell A
B) Cell B
C) Cell C
D) Cell A and Cell B
Free Response Question: Describe the differences between a prokaryotic and a eukaryotic
cell in terms of their rate of metabolic potential. Why is one type of cell more efficient than
the other? Give 2 examples of cells that have evolved to have increased surface area to
volume ratios and as a result are highly efficient.
Microvilli is an example of a cell
that is critical in the exchange of
materials. It has evolved to have
increased surface area and high
SA/V ratios and as a result is
highly efficient.
Answer Key LO 2.7
•
A)
B)
C)
D)
•
•
Multiple Choice Question: You are performing a lab experiment where you are examining three
cells. Cell A and Cell B each have a membrane bound nucleus and internal membranes. The
surface area to volume ratio of Cell A is larger than that of Cell B. Cell C appears to have no true
nucleus, and also lacks many of the membrane-enclosed organelles found in Cell A and Cell C.
Which of these cells would have a higher rate of nutrient intake?
Cell A
Cell B
Cell C
Cell A and Cell B
Free Response Question: Describe the differences between a prokaryotic and a eukaryotic cell in
terms of their rate of metabolic potential. Why is one type of cell more efficient than the other?
Give 2 examples of cells that have evolved to have increased surface area to volume ratios and as
a result are highly efficient.
A eukaryotic cell is much more efficient in its rate of metabolic potential than a prokaryotic cell. The
eukaryotic cell’s various membranes which are filled with enzymes help to increase the metabolic
rate of the cell. Eukaryotic cells maintain internal membranes that partition the cell into specialized
regions. Internal membranes facilitate cellular processes by minimizing competing interactions and
by increasing surface area where reactions can occur. A prokaryotic cells function a very basic level,
expending just enough energy to sustain themselves and reproduce. They do not have as many
membrane-enclosed organelles to help speed the process along. Two examples of cells that have
evolved to have increased surface area to volume ratios and as a result are highly efficient are hair
roots and cells of the Alveoli.
LO 1.15 The student is able to describe specific examples of conserved core biological processes and features
shared by all domains or within one domain of life, and how these shared, conserved core processes and
features support the concept of common ancestry for all organisms.
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.
M.C. Question:
Based on the character table, which
organisms are most closely related, and
why?
A. The shark and the lamprey, because
neither have lungs.
B. The tiger and the shark, because both
have jaws.
C. The gorilla and the human, because
both are bipedal.
D. Both A and B.
FRQ: Define and explain the ways that
phylogeny can be traced. Explain how
these methods can help provide us with a
clearer evolutionary history.
Explanation: Phylogenetic trees and cladograms can
represent traits that are either derived or lost due to
evolution. Phylogenetic trees and cladograms illustrate
speciation that has occurred, in that relatedness of any
two groups on the tree is shown by how recently two
groups had a common ancestor. Groups can be
monophylectic, paraphylectic, or polyphylectic.
Phylogenetic trees and cladograms can be constructed
from morphological similarities of living or fossil species,
and from DNA and protein sequence similarities.
Answer Key- LO 1.15
Multiple Choice
Free Response
Based on the character table,
which organisms are most
closely related, and why?
A. The shark and the lamprey,
because neither has lungs.
B. The tiger and the shark,
because both have jaws.
C. The gorilla and the human,
because both are bipedal.
D. Both A and B.
Define and explain the ways that phylogeny
can be traced. Explain how these
methods can help provide us with a
clearer evolutionary history.
Phylogeny can be traced through relative dating
and absolute dating. Relative dating is based
on the layer of soil that a fossil is found in. If
the fossil is found in a higher soil level, then
it is younger, and if it is found in a lower soil
level, then it is older. Absolute dating is
done through radiometric dating. It involves
using an isotope such as carbon-14, and
measuring the rate of decay to determine
how many years ago a fossil was alive.
These methods allow for a clearer
evolutionary history, because they provide
us with a timeline of evolution. We are able
to track a fossil through the years and
determine its features and see how they
have changed several years later.
LO 4.27- The student is able to make scientific claims and predictions about how species diversity within an ecosystem
influences ecosystem stability.
SP 6.4- The student can make claims and predictions about natural phenomena based on scientific theories and models.
Explanation- Species diversity is a term used to describe the number of different species represented in various populations. It is
directly proportional to an ecosystem’s stability, meaning that an ecosystem with low species diversity is more likely to have
individual species go extinct than a species with great diversity. This is because populations with greater diversity are more resilient
to changes in the ecosystem. Ecosystems with greater diversity are more resilient to change because they have more variation as a
result of mutations which could be potentially beneficial to survival. Keystone species are vital in maintaining species diversity
because they are species that make a large impact on the community. The loss of a keystone species will result in the lessening of
species diversity, in turn decreasing the ecosystem’s stability. Other factors that contribute to the maintenance of species diversity,
and the stability of the ecosystem as a whole, are producers, biotic factors, and abiotic factors.
Multiple Choice Question: In 1950 there was a world wide drought that affected all of the
ecosystems. Based on the chart to the right, keystone species played the most
instrumental role in which of the ecosystems and why?
A: Desert; it has the lowest number of species
B: Desert; following the drought, it experienced the lowest drop
C: Tropical Rainforest; it had the greatest number of species both before and after the
drop, meaning it was stable and resilient to change
D: Savanna; it experienced the greatest drop following the drought
Free Response Question: The Winston-Salem City Council plans to build a road through a portion of land that is currently
uninhabited, yet full of trees, bushes, grasses, and is home to a plethora of species.
A) What would be an ecologist’s primary concern with the building of a road through the field? Why would this be an issue?
B) Following the construction of the road, there is now two distinct habitats that evolve to be separate. How would the biodiversity
of one compare to the biodiversity of the other?
C) Would the ecosystem be more resilient to change before or after the construction of the road? Explain.
D) Explain why the loss of habitat poses a threat to biodiversity and survival of species in the ecosystem.
Multiple Choice Question: In 1950 there was a world wide drought that affected all of the
ecosystems. Based on the chart to the right, keystone species played the most
instrumental role in which of the ecosystems and why?
A: Desert; it has the lowest number of species
B: Desert; following the drought, it experienced the lowest drop
C: Tropical Rainforest; it had the greatest number of species both before and after
the drop, meaning it was stable and resilient to change
D: Savanna; it experienced the greatest drop following the drought
Based on the graph, the tropical rainforest had the greatest number of species, hovering
around 190 different species. In that ecosystem, it is evident the the keystone species
are doing their job to stabilize the biodiversity. Following the drought, the number of
species stayed about constant because the high level of biodiversity made it resilient to
change.
Free Response Question: The Winston-Salem City Council plans to build a road through a portion of land that is currently uninhabited, yet full of
trees, bushes, grasses, and is home to a plethora of species.
A) What would be an ecologist’s primary concern with the building of a road through the field? Why would this be an issue?
B) Following the construction of the road, there is now two distinct habitats that evolve to be separate. How would the biodiversity of one
compare to the biodiversity of the other?
C) Would the ecosystem be more resilient to change before or after the construction of the road? Explain.
D) Explain why the loss of habitat poses a threat to biodiversity and survival of species in the ecosystem.
A) An ecologist’s primary concern with the building of a road would be the habitat fragmentation. The road would cut the habitat in two,
lessening the number of species in each, which would in turn make species in each habitat more susceptible to change, increasing their chance
of extinction.
B) Assuming the species were evenly distributed throughout the portion of uninhabited land, once the road was build each of the two new
habitats should have roughly the same levels of biodiversity. Since species diversity is the number of species, rather than the number or
organisms of a species, the biodiversity of the two distinct habitats should be fairly similar since the range of the species was cut in half.
C) The ecosystem would be more resilient to change before the construction of the road. Since the ecosystem wouldn’t be divided, barriers
would not be intact, preventing organisms from mating. This would promote species diversity which would make the the ecosystem, as a whole,
less susceptible to change and extinction.
D) When the road was built, the ecosystem became two distinct habitats. Since the ecosystem is no longer one, barriers such as temporal
barriers and behavioral barriers would arise, eventually resulting in reduced hybrid variability and fertility. In the long run, the construction of the
road would lessen species diversity in each of the two new habitats, eventually causing the demise of many of the species.
LO 2.13: The student is able to explain how internal membranes and organelles contribute to cell functions.
SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices.
Explanation: Every part of the cell is essential to the survival and productivity of the cell. For example, internal membranes are vital to cells’
homeostasis due to their selectively permeable properties. Each individual organelle, in eukaryotes that is, is responsible for carrying out a
specific cell function. For example, the mitochondrion produce ATP through cellular respiration, and the chloroplasts are the sites of
photosynthesis, where oxygen is produced in plants. Confirmation of these specialized organelle functions can be tested through various
scientific experiments. For example, photosynthesis could be studied through the observation of percent light transmission in chloroplasts
when placed in a spectrophotometer under a variety of conditions (different colors of light, different temperatures, boiling/not boiling
chloroplasts, etc.) Through practices such as this one, experimenters are able to observe cell functions, in this case how and why
photosynthesis takes place.
M.C. Question: One of the most important concepts in many
aspects of biology is the idea that structure determines
function. This can be seen in proteins, for example in the “lock
and key” binding of a specifically shaped substrate to an enzyme
that fits that shape. If and only if these two fit can the enzyme
catalyze a reaction. This theory is also seen in the functioning of
various cell organelles. Which of the following is true concerning
how a specialized structure of an organelle determines its
function?
A) Chloroplasts have thylakoid membranes which cause protons
to accumulate, ultimately allowing the organelle to conduct
photosynthesis: the production of oxygen in all eukaryotic cells.
B) Mitochondrion have inner membranes that have an
intermembrane space between them. This space causes protons
to accumulate and move through ATP synthase, thus conducting
cellular respiration and producing ATP.
C) Ribosomes are able to conduct protein synthesis because of
the binding of DNA to the large subunit, one of the ribosome’s
two specific parts.
D) The true nucleus of a prokaryotic cell has coiled chromatin
that contains the majority of the genetic information, but some
of the cell’s DNA is also found in ribosomes.
FRQ: Photosynthesis is a complex cell process that only occurs in plant
cells. In a laboratory experiment recorded in the graph below, light
transmission was observed in different groups of chloroplasts, and one
control group with no chloroplasts.
a) Based on the diagram, which group had the most successful
photosynthetic rate? Explain why this occurred.
b) According to the graph, the “percentage of light transmission” was
measured in different groups over time. Explain what technique
could have been used to measure the percentage of light
transmission.
c)
Describe in detail the process of photosynthesis, including the
following:
i) Where photosynthesis takes place
ii) Products and reactants of
the process
iii) Why animal cells cannot
do this process
Graph source:
http://www.grochbiology.org/
aplabwriteupexample_files/
image004.gif
LO 2.13 ANSWER KEY
M.C. Question: Arguably one of the most important concepts in many aspects of biology is the idea that structure determines function. This can be seen in
proteins, for example in the “lock and key” binding of a specifically shaped substrate to an enzyme that fits that shape. If and only if these two fit can the
enzyme catalyze a reaction. This theory is also seen in the functioning of various cell organelles. Which of the following is true concerning how a specialized
structure of an organelle determines its function?
A) Chloroplasts have thylakoid membranes which cause protons to accumulate, ultimately allowing the organelle to conduct photosynthesis: the production
of oxygen in all eukaryotic cells.
- Incorrect – Only plant cells have chloroplasts, and thus only plant cells conduct photosynthesis.
B) Mitochondrion have inner membranes that have an intermembrane space between them. This space causes protons to accumulate and move
through ATP synthase, thus conducting cellular respiration and producing ATP.
- Correct – The unique structure of the inner mitochondrial membrane allows for the intermembrane space as well as the mitochondrial matrix. Protons are
forced through ATP synthase, which produces ATP in chemiosmosis, one of the steps of cellular respiration.
C) Ribosomes are able to conduct protein synthesis because of the binding of DNA to the large subunit, one of the ribosome’s two specific parts.
- Incorrect – Ribosomes conduct protein synthesis, but it is due to mRNA binding to the small subunit, not DNA binding to the large subunit. The function of
ribosomes is to translate mRNA into chains of amino acids: proteins.
D) The true nucleus of a prokaryotic cell has coiled chromatin that contains the majority of the genetic information, but some of the cell’s DNA is also found
in ribosomes.
- Incorrect – Prokaryotic cells do not have a true nucleus. They have one circular chromosome that is free-floating in the cytoplasm.
FRQ: Photosynthesis is a complex cell process that only occurs in plant cells. In a laboratory experiment recorded in the graph below, light transmission was
observed in different groups of chloroplasts, and one control group with no chloroplasts.
a)
Based on the diagram, which group had the most successful photosynthetic rate? Explain why this occurred.
- The unboiled chloroplasts that were exposed to light had the most successful photosynthetic rate. This occurred because they absorbed the most light
energy and were in their natural state: unboiled. Chloroplasts in the dark were not exposed to light, so they could not conduct photosynthesis because they
could not take in any light energy. Being boiled also contributed to photosynthetic failure because they were disturbed and not in their natural, ideal
conditions.
b)
According to the graph, the “percentage of light transmission” was measured in different groups over time. Explain what technique could have been
used to measure the percentage of light transmission.
- To measure percentage of light transmission, chloroplasts could be placed into cuvettes and into a spectrophotometer. This instrument, once blanked and
set to a specific wavelength, can measure the percentage of light transmission through the chloroplasts. This data can then be used to calculate
photosynthetic rates.
c) Describe the process of photosynthesis, including the following:
i) Where photosynthesis takes place – Photosynthesis takes place in the chloroplasts of plant cells, specifically in the thylakoid membranes which
contain chlorophyll.
ii) Products and reactants of the process – Photosynthesis is the process of plants taking in carbon dioxide, water, and light energy from the
atmosphere and converting it into glucose, oxygen, water, and chemical energy in the form of ATP.
iii) Why animal cells cannot do this process – Animal cells cannot conduct the process of photosynthesis because they do not have chloroplasts.
Chloroplasts, and their thylakoid membranes they have inside, are unique to plant cells and are necessary to take in light energy and carry out
photosynthesis properly.
LO 2.18: The student can make predictions about how organisms use negative feedback mechanisms to maintain their
internal environments.
SP 6.4: The student can make claims and predictions about natural phenomena based on
scientific theories and models.
Explanation: Organisms use feedback mechanisms to maintain their internal environments and respond to external
environmental changes. They do this by returning the changing condition back to its target set point to help maintain
homeostasis. Negative feedback is a mechanism that either turns a process on or off, like a light switch. It occurs when
the rate of the process decreases as the concentration of the product increases which controls the rate of a process to
avoid accumulation of a product. For example, when humans get to hot, they sweat to help cool off. Another example is
with operons in gene regulation. The repressor or protein that shuts off the operon is made when it binds to Trp. When
there is enough Trp around, the Trp operon shuts off so that the cells can focus on other processes.
M.C. Question: T3 and T4 are hormones produced by the Thyroid gland in
the neck and are regulated by TSH from the pituitary gland in the brain. T3
acts by modifying gene transcription in virtually all tissues to alter cell
metabolism. T4 is the precursor to T3. If a person has an overproduction of
the thyroid hormones, T3 and T4, you would expect their TSH levels to do
what? Refer to the diagram to the right.
A) Rise
B) Decline
C) Stay the same
D) Fluctuate
Learning Log/FRQ-style Question: A person with Type II diabetes
has insulin resistance forcing beta cells in the pancreas to produce
large amounts of insulin to overcome that resistance. As the high
levels of insulin in the diabetic bring the blood sugar down, what
happens to the beta cells producing the insulin? Suppose a you
have high blood glucose levels. Explain how negative feedback
mechanisms will regulate your blood levels back to normal. How
would negative feedback mechanisms regulate your blood back to
normal if you have low blood glucose levels?
"ReviseScience.co.uk." ReviseScience.co.uk. N.p., 1
Jan. 2005. Web. 27 Apr. 2014.
<http://www.revisescience.co.uk/2011/schools/gayn
es/21b210.asp>.
Answer Key- LO 2.18
T3 and T4 are hormones produced by the Thyroid gland in the neck and are regulated by TSH from the pituitary
gland in the brain. T3 acts by modifying gene transcription in virtually all tissues to alter cell metabolism. T4 is
the precursor to T3. If a person has an overproduction of the thyroid hormones, T3 and T4, you would expect
their TSH levels to do what? Refer to the diagram to the right.
A)
B)
C)
D)
Rise- wrong because the body would think there was already enough
Decline- correct because as the thyroid hormones rise, they inhibit TSH (thyroid stimulating hormone)
slowing the production of hormones from the thyroid gland
Stay the same- wrong because the body is constantly trying to achieve homeostasis
Fluctuate – wrong because there is a negative correlation between the thryoid hormones and the TSH
A person with Type II diabetes has insulin resistance forcing beta cells in the pancreas to produce large
amounts of insulin to overcome that resistance. As the high levels of insulin in the diabetic bring the blood
sugar down, what happens to the beta cells producing the insulin? Suppose a you have high blood glucose
levels. Explain how negative feedback mechanisms will regulate your blood levels back to normal. How would
negative feedback mechanisms regulate your blood back to normal if you have low blood glucose levels?
As the high levels of insulin in the diabetic bring the blood sugar down, the beta cells are turned off to
maintain a minimum level of glucose in the blood stream. When blood glucose levels are high, the
production of insulin from the pancreas increases. Insulin transports the glucose into the cells to be used for
energy. As the glucose levels fall it slows the production of insulin to maintain homeostasis. If the blood
glucose levels fall to far, the production of insulin decreases while the production of adrenalin increases to
stimulate the muscle to breakdown glycogen into glucose. This also stimulates gluconeogenesis in the liver.
LO 3.6: The student can predict how a change in a specific DNA or RNA sequence can result in changes in a gene
expression.
SP 6.4: Students can make claims and predictions about natural phenomena based on scientific theories and models.
Explanation: Random changes in DNA nucleotide sequences can lead to heritable mutations if they are not repaired. These
mutations can consist of translocation (the chromosome moves to a different site), nondisjunction (chromosome fails
to separate), duplication (chromosome segment doubles), and deletion (chromosomal segment is removed). Mutations
can potentially alter levels of gene expression, pr remain silent and unnoticeable. These changes in a nucleotide
sequence, if present in a protein-coding region, can change the amino acid sequence of the polypeptide. The product
of the cells are controlled by the expression of the genetic material inside of it, and the product determines the nature
of the cell. So if it is alter in any way, the nature of the cell could potentially be changed. Gene expression is regulation
by environmental factors, like cell communication and cell peer pressure. But it is also regulated by developmental
factors, which could be the sequence of DNA that is given . All of these are factors that can alter DNA or RNA
sequences, causing them to change. The result of these alterations could be mutations, diseases, which can lead to the
gene expression to physically change. Just because the genotype changes doesn’t mean the phenotype does, but the
gene expression will.
MC: Which of these figures best describes genetic deletion?
A)
B)
C)
D)
FRQ: Mutations in a DNA sequence can alter gene expression. Define the following examples and explain how each
example can alter a gene expression.
a) translocation
b) nondisjunction
c) duplication
d) deletion
FQR pointers and starting points:
a) Translocation is the movement of a chromosome segment to a different site. Translocation can be balanced, which
means there is an even exchange in genetic material. But it can also be unbalanced, causing extra or missing genes. You
can test for this with prenatal diagnosis.
a) Nondisjunction is the separation failure of a chromosome. This means sister chromatids did not separate properly
during cell division. It can result in an abnormal amount of chromosomes, like aneuploidy.
b) Duplication is the doubling of chromosomal segments. Duplication can result in recombination, aneuploidy and
polyploidy. It can cause many errors in the DNA sequence and genetic material,
c) Deletion is the removal of a chromosomal segment. It is the direct loss of genetic material.. Deletion can cause many
problems with crossing over during meiosis, and also scan lead to serious genetic diseases. Deletion also can cause a
frameshift in the DNA sequencing meaning that a whole fragment of the DNA strand moves over completely jumbling
up the DNA code. It causes losses from translocation, unequal crossing over, breaking without rejoining the segment,
and chromosomal crossover within a chromosomal inversion.
LO 1.8: The student is able to make predictions about the effects of genetic drift, migration and artificial selection on the genetic makeup of a
population.
SP 6.4: The student can make claims and predictions about natural phenomena based on scientific theories and models.
Explanation: Evolutionary mechanisms such as genetic drift, migration, and artificial selection, disrupt Hardy-Weinberg Equilibrium by changing
genotype frequencies in populations. Genetic drift (changes in relative allele frequency) is a nonselective process that usually occurs in
small populations where infrequently-occurring alleles face a greater chance of being lost. Migration is the movement of organisms from
one place to another and it can increase or decrease allele frequencies in populations. After mating is established between the migrating
and the original individuals, the migrating individuals will contribute gametes carrying alleles that can alter the existing proportion of alleles
in the original population. Selective breeding of organisms, also known as artificial selection, produces organisms with more desirable
traits. Many researchers can use these organisms to test genetic variation in a population. Hardy-Weinberg Equilibrium states that allele
and gene frequencies in a population will stay the same unless acted on by other evolutionary influence. All three of these disrupt the
Equilibrium and decrease genetic variations which can then lead to an increase in the differences between two populations of the same
species.
M.C. Question: According to the Hardy-Weinberg Equilibrium there
are five factors that play a role in evolutionary changes in
populations. Which of the following is NOT one of these
factors.
A. Natural selection
B. Non-random mating
C. Mutations
D. Habitat fragmentation
E. Genetic drift
Learning Log/FRQ-style Question: You are a researcher that has gone
into the field and sampled a population of birds in which you
find that the percentage of the bird’s that display the recessive
phenotype of black wings is 49%, calculate the following allele
frequencies:
A. The frequency of the “aa” genotype.
B. The frequency of the “a” allele.
C. The frequency of the “A” allele.
D. The frequencies of the genotypes “AA” and “Aa.”
ANSWER KEY- LO 1.8
M.C. Question: According to the Hardy-Weinberg Equilibrium there are five
factors that play a role in evolutionary changes in populations. Which of the
following is NOT one of these factors.
A. Natural selection
Habitat fragmentation is the right answer
B. Non-random mating
because although it would cause evolutionary
C. Mutations
changes in a population, it is specifically not
D. Habitat fragmentation
one of the five factors that is listed in the
E. Genetic drift
Hardy-Weinberg Theory.
Learning Log/FRQ-style Question: You are a
researcher that has gone into the field and
sampled a population of birds in which you
find that the percentage of the bird’s that
display the recessive phenotype of black
wings is 49%, calculate the following allele
frequencies:
A. The frequency of the “aa” genotype.
B. The frequency of the “a” allele.
C. The frequency of the “A” allele.
D. The frequencies of the genotypes “AA” and
“Aa.”
A. aa= 49%=q²=.49
B. q²= .49
q= .7
C. p+q=1
p+.7=1
p= .3
D. AA= p²= (.3)²= .09
Aa= 2pq= 2(.3)(.7)= .42
LO 3.12: The student is able to construct a representation that connects
the process of meiosis to the passage of traits from parent to offspring.
•Explanation: Meiosis allows offspring to inherit traits from its
parents without being a genetic copy of the previous generation.
Any cell with two chromosome sets is a diploid cell, abbreviated
2n. Haploid cells contain a single chromosome set, abbreviated n.
In humans, n=23, meaning that in each gamete the haploid
number of chromosomes is 23, and our diploid number would be
46 (23x2). In meiosis, chromosomea from each parent are
donated. The homologous pairs of chromosomes in a diploid
parent cell each replicate, forming 2 sister chromatids in the
diploid. In Meiosis I, these homologous chromosomes separate,
forming two haploid cells with replicated chromosomes from
parents. Then in meiosis II, these two separate sister chromatids
split again, forming four haploid cells, all with unreplicated
chromosomes. In prophase 1 of the meiosis 1 stage, these dna
molecules in the nonsister chromatids break at a specific place,
then rejoin at the other chromatid. This is called crossing over,
which is one of the main causes for genetic variation in meiosis
and reproduction.
LO 3.12 Practice
•MC Question: Genetic rearrangements between two non sister chromatids,
commonly known as crossing over, occurs in which of the following stages of meiosis?
• A. Prophase II B. Metaphase I C. Prophase I D. Metaphase II
•FRQ Question: Sexual reproduction needs chromosomes donated from two seperate
parent organisms to ignite meiosis and the growth of an offspring, with each parent
giving half of the total chromosomes to the mix. Name on species that reproduces
sexually, and describe the mode in which genetic information is transferred to keep
variation between the parent and offspring organisms.
Practice Answers


Multiple Choice: Answer is C, Crossing over occurs in prophase I of
meiosis I.
FRQ: Humans are a species that use sexual reproduction to
generate new, genetically differing offspring. It is necessary to have
two parents, one male and one female, to produce one egg and
one sperm cell to begin meiosis. These two gametes (1n each) join
in fertilization, creating a diploid cell (2n). Once the diploid cell is
created, chromosomes replicate to form sister chromatids. These
chromatids meet in the center of the parent cell, and exchange
parts of the chromatids to one another in prophase I, prior to the
division of these chromatids. This step is known as switching over,
which takes chromatin from one chromatid and exchanges it with
another, ensuring that the offspring is not a genetic copy of the two
parents.
LO 4.16: The student is able to predict the effects of a change of matter or energy availability on communities
SP 6.4: The student can make claims and predictions about natural phenomena based on scientific theories and
models.
Competition and cooperation are vital in ecosystems. As is seen in food webs and other interactions, organisms in
a community are heavily connected. Competition and competition go all the way down to molecular levels. For
example, inhibitors may compete for the same active site of enzymes. Cells also compete with each other; for
example, spores have to compete with each to survive. Cooperation is also vital within an organism. The
organism’s parts have to cooperate all the way from a molecular level to the organ systems cooperating. Finally,
organisms interact with each other and their environment. The exchange of oxygen and carbon dioxide in plants
and animals is vital to both groups. A change in matter or energy can disrupt this entire web of interactions and
cooperation and force more competition among an ecosystem.
Multiple Choice Question:
Use the food web to the left to answer the following question. If hunting
became an issue in the ecosystem and the biomass of deer was greatly
diminished, which of the following populations would be the most directly and
immediately affected?
A. The shrew population would increase as a result of more insects
B. The cougar would begin to eat mice as an alternative food source
C. The snake would face new competition from the cougar
D. The rabbit population would decrease as a result of increased predation
E. A new herbivore would replace the deer in the web, which would initially
decrease the grass population.
Consider the following: Consider a small ecosystem with producers, primary
consumers, and secondary consumers. If sunlight was somehow blocked and the
ecosystem received less light energy, describe the effect it would have on the
producers, primary consumers, and secondary consumers. Explain these
predictions. Draw a graph showing the population size of each in relation to
available light energy.
Use the food web to the left to answer the following question. If hunting became an issue in the ecosystem
and the biomass of deer was greatly diminished, which of the following populations would be the most
directly and immediately affected?
A.
The shrew population would increase as a result of more insects- while this could potentially happen
as a result of more grass, it is not the most direct and immediate result.
B.
The cougar would begin to eat mice as an alternative food source- while this could again in theory
happen, it is unlikely that the dietary limitations of the cougar could change like that and even if they
could it would not be immediate and direct
C.
The snake would face new competition from the cougar-this is very similar to b. Just as in b, it is
unlikely that the cougar would begin to prey on the snake’s food source and even if it did it is not
the most direct and immediate result.
D.
The rabbit population would decrease as a result of increased predation- if the deer
population is greatly diminished, the cougars will have to consume more rabbits in order to
sustain themselves.
E.
A new herbivore would replace the deer in the web, which would initially decrease the grass
population.-this is incredibly unlikely and if it replaced the deer, the grass population would remain
fairly constant, not decrease.
Consider the following: Consider a small ecosystem with producers, primary consumers, and secondary consumers. If sunlight
was somehow blocked and the ecosystem received less light energy, describe the effect it would have on the producers, primary
consumers, and secondary consumers. Explain these predictions. Draw a graph showing the population size of each in relation to
available light energy.
If sunlight was blocked, there would be less light energy available to the population. Light energy is used in photosynthesis, meaning
producers would struggle. Producers are photosynthetic organisms that convert light energy into usable energy. Because of decreased
available light energy, the producer population would likely decrease. Also, without the photosynthesis, there will be more carbon
dioxide and less oxygen in the air, which could be harmful to organisms that require oxygen. The primary consumers will suffer mostly
from the decrease in the producer population. Producers are their food source, so as the producer population decreases, the primary
consumer population will decrease. In the same manner, the secondary consumer population will decrease as the population of their
food source, the primary producer, decreases.
Key
Producers
Primary consumers
Secondary consumers
Population size
Available sunlight energy
As the available light energy increases, the
populations of all three groups increase.
Producers have to have the highest
population because only about ten percent
of energy is passed on to each trophic level.
LO 2.38 The student is able to analyze data to support the claim that responses to information and communication of information
affect natural selection [SP 5.1]
SP 5.1 The student can analyze data to identify patterns or
relationships.
Connection:
•
The responses to information and communication of information affects
natural selection come from the way organisms interact with the
environment and with other organisms. A graph showing the period of
dormancy during hibernation can be evaluated to determine how the
individuals body functions are slowed down to the point where normal
energy consumption is temporarily slowed. Other graphs that can be
drawn from include courtship periods of the year or even migratory
patterns due to the environment. These graphs that are analyzed can
show patterns or relationships between different species. The student
can then claim that the survival and reproduction that presents natural
selection is valid in the way organisms interact to the environment as
well as other organisms. Sometimes populations interact with each
other to better themselves and the community. This role it plays is
called its niche. The way organisms interact can be described as
mutualism, commensalism, or parasitism. These responses help a
species survive and reproduce to pass on their favorable traits. This
leads to biodiversity and the strongest will survive according to natural
selection.
Free response:
According to the data of both the graph and the table, answer
the following question. There was a drought in the years 20002002. Why did the drought affect the size of the birds beaks?
Explain the food sources as well as the size of the beaks. Use
thesize
graph and chart to justify your answer.
Beak
Small
300
150
0
300
400
Medium
1400
1200
600
900
1100
Large
300
650
1400
800
500
2001
2002
2003
2004
Year 2000
Multiple choice:
In the graph below shows the number of
finches in the area during a drought. The larger
seeds come from tall trees that have longer, wider
roots that allow for more water to be absorbed.
While the small seeds come from ground plants
with smaller roots that cannot soak up the little
water as easily. From the data given, which
answer choice best explains why small beak size is
NOT favored during the period of drought?
a) The smaller beak size allows the birds to
penetrate the larger nut. Natural selection
has favored the smaller, more brittle
beaks.
b) The smaller beak size does not have the
power to consume the larger seeds.
Natural selection has favored the larger
beak size and these birds have passed on
their favorable trait.
c) The smaller beak size does not weigh
the birds down. Therefore they are more
likely to survive when running from
predators.
d) The smaller beak size does not have the
ability to absorb nutrient from the large
nuts. This is why they moved away.
Page
Multiple choice:
In the graph below shows the number of finches in the
area during a drought. The larger seeds come from tall
trees that have longer, wider roots that allow for more
water to be absorbed. While the small seeds come from
ground plants with smaller roots that cannot soak up
the little water as easily. From the data given, which
answer choice best explains why small beak size is NOT
favored during the period of drought?
•
a) The smaller beak size allows the birds to
penetrate the larger nut. Natural selection has
favored the smaller, more brittle beaks.
•
b) The smaller beak size does not have the power
to consume the larger seeds. Natural selection
has favored the larger beak size and these birds
have passed on their favorable trait.
•
c) The smaller beak size does not weigh the birds
down. Therefore they are more likely to survive
when running from predators.
•
d) The smaller beak size does not have the ability
to absorb nutrient from the large nuts. This is why
they moved away.
Answers: Page 2/2
Free response:
According to the data of both the graph and the table, answer the
following question. There was a drought in the years 2000-2002. Why
did the drought affect the size of the birds beaks? Explain the food
sources as well as the size of the beaks. Use the graph and chart to
justify your answer.
Answer:
The drought has an effect on the birds because the drought causes the
larger trees to soak up the little water that is present in the ground.
Large trees have larger roots and cover a larger surface area. These
large trees have caused the smaller shrubs and smaller trees to not
absorb enough water needed to survive. Thus a shortage of smaller
seeds is present and larger seeds are the remaining food source. The
birds with the small beaks are not able to eat the large seeds therefore
they have run out of their food supply. The large beaked birds survive
and are able to reproduce. This is natural selection playing its role in
the environment. When an environment lacks the right food supply for
a species, it will die and another species can take its place. As the
graph shows with the drought comes a shift and an increase in the
number of large beak birds and a decline in small and medium beaked
birds. The table has the same information in number form. The table
shows that during the drought the small beaked bird numbers decline
along with the medium beak birds until the small beak birds reaches
Beak size
zero. On the other hand the large beak birds are able to find food and
to reproduce and
to 1400 birds.
Small survive 300
150 increase their
0 population
300
400Once
the drought is over, the numbers begin to return to the original state
Medium
1400
1200
600
900
1100
and the small beak to large beak ratio almost equalizes again while the
Large medium300
beaks rise. 650
1400
800
500
Year 2000
2001
2002
2003
2004
LO 3.9: The student is able to construct an explanation, using visual representations or narratives, as to
How DNA in chromosomes is transmitted to the next generation via mitosis, or meiosis followed by
Fertilizations
SP 6.2:The student can construct explanations of phenomena based on evidence produced through
scientific practices.
Explanation: During meiosis, DNA begins on the chromosomes that replicate during S-phase and proceed to prophase I
where crossing occurs that helps create genetic variability by also exchanging DNA. The cell then undergoes Telephase I to
divide it (this process was studied by Mendel who theorized the idea of homologous chromosomes separating). The
resulting two cells under go meiosis II and produce the 4 haploid gametes that contain single chromosomes containing the
unique genes/DNA. This is where recessive and dominant alleles get put on the locus on the final gametes that are
produced. The gametes from each parent come into contact with each other during reproduction and fertilization
(combination of the haploid sperm cell with the haploid ovum) occurs. The resulting zygote is diploid and represents the
combined haploid sets of chromosomes/DNA from the parents.
M.C. Question: A homozygous dominant red flower (RR) is crossed with a heterozygous white flower (rr).
What is the ratio of the colors in the F2 generation.
A) 1:3
B) 1:1:1
C) 1:2:1
D) 2:1:1
Learning Log/FRQ-style Question: Attached is a
pedigree of Bailey’s family. Her great grandmother,
and both uncles have both been afflicted with RedGreen color blindness. One of her brothers is also
afflicted with the disease. However neither her nor
her sister have the disease. When she marries, does
her son have chance of getting the disease? Also,
explain why one brother and not the other has the
disease.
Learning Log question
Bailey
ANSWER KEY– LO 3.9
M.C. Question: A homozygous dominant red flower (RR) is crossed with a heterozygous white flower (rr).
What is the ratio of the colors in the F2 generation.
A) 1:3
B) 1:1:1
C) 1:2:1/ 1: homozygous dominant red, 2: heterozygous pink, and one homozygous recessive white
D) 2:1:1
Learning log question: Attached is a pedigree of Bailey’s family. Her
great grandmother, and both uncles have both been afflicted with
Red-Green color blindness. One of her brothers is also afflicted
with the disease. However neither her nor her sister have the
disease. When she marries, does her son have chance of getting
the disease? Also, explain why one brother and not the other has
the disease.
Answer: Her son does have a chance of getting the disease,
because Red-Green color blindness is an X-linked disease. That is
why it makes sense for her, her sister, and mother to not show
signs of the trait but her brother does have it. However, this does
mean that she could very well be a carrier. With her mother
having two daughters, the chances of one of them at least being a
carrier is close to, if not 100%. The reason that one of her
brothers has the disease and the other one doesn’t, is a result of
the mother being a carrier. She has two X chromosomes with one
of them having the disease on it. This results in a 50% chance of
having a son with the disease. In this case, the family is a perfect
statistical representation. Each of the sons has a 50% of catching
the disease; and one did while the other did not. While one of
the daughters is most likely a carrier.
Works cited
http://classconnection.s3.amazonaws.com
/65/flashcards/816065/png/xlinked_r1318385614753.png
http://mrsmarsigliano.weebly.com/uploa
ds/2/4/8/0/24807467/2299956_orig.jpg
Learning Objective 1.30 The student is able to evaluate scientific hypotheses about the origin of life on Earth.
Science Practice 6.5 The student can evaluate alternative scientific explanations.
Explanation: The “Organic Soup” theory hypothesized that electrical energy could catalyze the gases in the atmosphere of the early Earth to create biomolecules that. Experiments (such as the Miller-Urey
Experiment) were able to mimic electrical discharges through which water and gasses (hydrogen, methane, and ammonia gas) passed in order to mimic the atmospheric makeup of early Earth and its
interaction with lightning, radioactivity, and UV light. The energy from the charge caused various amino acids and some nucleic acids to form and over time, these molecules became more complex and acted
together to run metabolic processes. Some models suggest that primitive life developed on biogenic surfaces, such as clay, that served as templates and catalysts for assembly of macromolecules. Under
laboratory conditions, complex polymers and self-replicating molecules can spontaneously assemble. It remains an open question whether the first genetic and self-replicating material was DNA or RNA.
The “Ocean Vents Theory” hot, pressurized water mixed with dissolved gases (including hydrogen sulfide, carbon monoxide, carbon dioxide, hydrogen cyanide and ammonia) passed out of prehistoric vents and
over various minerals containing iron, nickel and other metals within the rocks around the vents. These metals served as catalysts for a chain reaction that synthesized organic compounds and coupled some of
them with other metals to form new compounds with greater ability to yield new chemical reactions. This coupling between the catalyst and the product of an organic reaction is the key first step of
Wächtershäuser’s theory. Starting with these metals and gases reacting together as life emerged, Wächtershäuser says evolution starts with the beginning of a primitive metabolism that created increasingly
complex chemical reactions (chemosynthesis), eventually leading over time to the formation of DNA — life’s blueprints for making more living cells today. Chemosynthesis is the biological conversion of carbon
molecules and nutrients into organic matter — the stuff of life. Whereas photosynthesis uses energy from sunlight to convert carbon dioxide into that organic matter, giving off oxygen as a byproduct,
chemosynthesis uses inorganic molecules (such as hydrogen sulfide) or methane and combines them with an oxygen source (in this case seawater) to create simple sugars.
The Extraterrestrial theory suggests that comets and meteorites striking the Earth attributed to the creation of organic matter. In support of this theory, we know that organic compounds are relatively
common in space and that Uracil, a component of RNA, likely formed extraterrestrially. We also know that comets contain complex organic material such as coal.
Though there are differing hypotheses about the origin of life, the following scientific evidence supports the various models:
1. Primitive Earth provided inorganic precursors from which organic molecules could have been synthesized due to the presence of available free energy and the absence of a significant quantity of oxygen.
2. In turn, these molecules served as monomers or building blocks for the formation of more complex molecules, including amino acids and nucleotides.
3. The joining of these monomers produced polymers with the ability to replicate, store and transfer information.
4. These complex reaction sets could have occurred in solution (organic soup model) or as reactions on solid reactive surfaces.
5. The RNA World hypothesis proposes that RNA could have been the earliest genetic material.
The Miller-Urey Experiment
MCQ: Which of the following hypothesis the origin of life would & most closely relate to the belief
that the interaction of terrestrial elements and electrostatic discharge contributed to the
formation of Earth’s first biotic substances?
A. Ocean Vent
B. Primordial Soup
C. Extraterrestrial Theory
D. both A and C
FRQ: Identify and explain one of the theories on the origin of life and briefly explain
how, in two ways, it specifically differs from another hypothesis of biological merit.
MCQ: Which of the following hypothesis the origin of life would & most closely relate to the belief that the interaction of
terrestrial elements and electrostatic discharge contributed to the formation of Earth’s first biotic substances?
A. Ocean Vent
B. Primordial Soup
C. Extraterrestrial Theory
D. both A and C
Explanation: The correct answer is B, as the Miller-Urey experiment (supporting this theory) explains and demonstrates the relationship between
lightning and other photo-interference and the gases present on early Earth, and how this interaction produces life from non-life.
FRQ: Identify and explain one of the theories on the origin of life and briefly explain how, in two ways, it specifically differs from other hypotheses.
Response: An often-told origin-of-life story is that complex biological compounds assembled by chance out of an organic broth on the early Earth's
surface, many times referred to the Primordial Soup Theory. This pre-biotic synthesis culminated in one of these bio-molecules being able to make
copies of itself. The first support for this idea of life arising out of the primordial soup came from the famous 1953 experiment by Stanley Miller and
Harold Urey, in which they made amino acids—the building blocks of proteins—by applying sparks to a test tube of hydrogen, methane, ammonia,
and water. If amino acids could come together out of raw ingredients, then bigger, more complex molecules could presumably form given enough
time. Biologists have devised various scenarios in which this assemblage takes place in tidal pools, near underwater volcanic vents, on the surface of
clay sediments, or even in outer space. Many researchers, therefore, think that RNA—a cousin of DNA—may have been the first complex molecule on
which life was based. RNA carries genetic information like DNA, but it can also direct chemical reactions as proteins do. However in the deep sea vent
theory poses that hot, pressurized water mixed with dissolved gases (including hydrogen sulfide, carbon monoxide, carbon dioxide, hydrogen cyanide
and ammonia) passed out of prehistoric vents and over various minerals containing iron, nickel and other metals within the rocks around the vents.
These metals served as catalysts for a chain reaction that synthesized organic compounds and coupled some of them with other metals to form new
compounds with greater ability to yield new chemical reactions. The Primordial Soup theory does not take into account the potential of hydrogen
sulfide, and it also focuses its attention on the interaction between electrical stimulus rather than heat stimulus.
LO 3.3: The student is able to describe representations and models that illustrate how genetic
information is copied for transmission between generations.
Sp 1.2: The student can describe representations and models of natural or man-made
phenomena and systems in the domain.
Explanation: Heritable information that is needed for organizational purposes of all living organisms, is stored
and passed to generations by DNA. Chromosomes contain the genetic information necessary for protein
synthesis and transmission into daughter cells. Prokaryotes contain circular chromosome, while Eukaryotes
have multiple linear chromosome. Before the process of mitosis and meiosis, DNA is replicated during
Interphase. Interphase contains three parts, G1, S, and G2. DNA synthesis occurs in the S phase, while growth
of cell occurs in G1 and G2. DNA synthesis, replication, ensures continuity of heritable information. This is
because daughter cells receive an identical and complete set of chromosomes, which are copied in during DNA
synthesis and distributed during mitosis/meiosis. The enzymes, DNA polymerase, adds on corresponding
nucleotides to the new strand by reading the template strand. DNA polymerase works in a 5’ to 3’ manner by
adding each new base to the 3’ end. Because DNA is antiparallel, there will be a leading and lagging strand.
MC Question: What is the role of molecule 5 in the
diagram of DNA synthesis,
A) Adds new nucleotides to the new strand
B) Proofreads the new DNA strand
C) Joins to together fragments with the use of
Hydrogen bonds
D) Unwinds double helix, breaking the hydrogen
bonds
Free Response/Learning Log Question
a) Using figure 1, describe the role of the molecules (by name) in the process of DNA replication.
b) DNA replication is necessary for transmission of genetic material between generations, explain MeselsonStahl’s experiment in determining how DNA replicates in a semiconservative manner and provide a diagram of
this replication
What is the role of molecule 5 in the diagram of DNA
synthesis,
A) Adds new nucleotides to the new strand
B) Proofreads the new DNA strand
C) Joins to together fragments with the use of
Hydrogen bonds
D) Unwinds double helix, breaking the hydrogen
bonds
C is the correct answer because in the diagram, molecule 5 represents DNA ligase. The role of DNA ligase is to
bind okazaki fragments together forming a complete strand.
a) Using figure 1, describe the role of the molecules (by name) in the process of DNA replication.
b) DNA replication is necessary for transmission of genetic material between generations, explain
Meselson-Stahl’s experiment in determining how DNA replicates in a semiconservative manner and
provide a diagram of this replication
a)
b)
The template DNA strand is first unzipped at the origins of replication by the enzyme, helicase. On the
leading strand, DNA polymerase reads the template strand and continuously adds on nucleotides to
the 3’ end of the new strand. On the lagging strand, primase synthesizes RNA primers at the beginning
of each Okazaki fragment. DNA polymerase can then add nucleotides to each primer until it reaches
the next one. DNA ligase comes in to form bonds between each fragment, thus completing the strand.
Meselson and Stahl performed an experiment using E. coli bacteria. They first cultured the bacteria in
a heavy isotope of nitrogen, N15. Then, they transferred the bacteria into a lighter isotope, N14, in
order for the bacteria to synthesize. The DNA was centrifuged for 40 minutes to show two replications.
The first replication displayed a band of DNA that was a hybrid of the two and the second replication
displayed band of both a hybrid and light DNA. This represented the semiconservative model.
Continue to slide 3 for the diagram.
First replication
Second Replication
(LO 4.4) The student is able to make a prediction about the interactions of subcellular organelles.
(SP 1.5) The student can make claims and predictions about natural phenomena based on scientific theories
and models.
A eukaryotic cell has membrane-enclosed organelles, the largest of which is
usually the nucleus. A prokaryotic cell is usually smaller and does not
contain a nucleus or other membrane-enclosed organelles. Some
organelles are animal or plant specific, but these SEVEN organelles
are found in both types of cell: the nucleus, vacuole, mitochondria,
the Golgi apparatus, cytoskeleton, peroxisomes, and the
Endoplasmic reticulum (ER). The nucleus includes the nuclear
envelope, the nucleolus, and chromatin, and is the information center
of the cell. A vacuole is a membrane-bound sac that contains
hydrolytic enzymes that aid in intracellular digestion and the release
of cellular waste products. There is a central vacuole in plant cells.
Mitochondria aid in energy capture and transformation. The Golgi
apparatus, consisting of a series of flattened membrane sacs (called
cisternae), synthesizes and packages small molecules for transport in
vesicles, and produces lysosomes (described later). The cytoskeleton
reinforces the cell’s shape. The ER consists of a smooth and a rough
ER. The rough ER gets its name from its surface containing ribosomes
(small structures containing rRNA and protein) and is where protein
synthesis occurs and contributes to intracellular transport. Ribosomes
can be free ribosomes (suspended in the cytosol) or bound ribosomes
(attached to the outside of the ER or nuclear envelope). The smooth
ER synthesizes lipids. Peroxisomes are organelles that aid in
metabolism and produce hydrogen peroxide.
MC Question:
The endomembrane system is a complicated system involving
multiple organelles. Which of the following correctly describes the
movement through this system of a protein that functions best in
the ER?
A. The mRNA is synthesized in the ER, translated on a free ribosome
to the Golgi, and then a transport vesicle carries the mRNA back to
the ER for modification. The mRNA is then sent to the nucleus.
B. The mRNA is synthesized in the Golgi, is translated on a free
ribosome to the ER for modification, and then a transport vesicle
carries the mRNA back to the Golgi.
C. The mRNA is synthesized in the nucleus, is translated on a free
ribosome, then is sent to the Golgi and modified. A transport
vesicle carries the protein to the ER for further modification.
D. The mRNA is synthesized in the nucleus, is translated on a bound
ribosome, then is sent to the ER and modified. A transport vesicle
carries the protein to the Golgi apparatus. After modification in the
Golgi, another transport vesicle carries the protein back to the ER.
FRQ Question:
Organelles are found in both prokaryotic and eukaryotic cells.
Plant cells include chloroplasts, organelles that contribute to energy
a. Compare and contrast prokaryotic and eukaryotic cells.
capture and conversion for photosynthesis. Animal cells contain
b. List and describe the basic function of three organelles.
lysosomes, which aid in intracellular digestion, apoptosis, and
c. Describe how these organelles work together to allow the animal
recycling cell material. Centrosomes are organelles where the cell’s
microtubules are initiated, but in animal cells these organelles contain cell to function.
centrioles (function unknown). Plant cells also contain a cell wall, with
plasmodesmata (channels) throughout, that help keep the cell’s
shape and protect the cell from mechanical damage. (next slide has
visuals)
Organelle Interactions
Now that we know the functions of the organelles,
let’s look at how they interact…
The nucleus houses the most of the cell’s
DNA and the ribosomes use
information from the DNA to make
proteins. Vesicles move from the ER
to the Golgi. Vesicles form and leave
Golgi, carrying specific proteins to
other locations or to the plasma
membrane for secretion. Vesicles
also transport certain proteins back
to the ER. These vesicles give rise to
lysosomes and vacuoles. Lysosomes
are then available for fusion with
another vesicle for digestion.
Transport vesicles carry proteins to
the plasma membrane for secretion.
The Plasma membrane expands by
fusion of the vesicles and the
proteins are secreted from the cell.
This makes up the endomembrane
system. In addition to this system,
mitochondria (animal cells) and
chloroplasts (plant cells) contain DNA
and change energy from one form to
another.
Answer Key- LO 4.4
FRQ:
Organelles are found in both prokaryotic and eukaryotic cells.
a. Compare and contrast prokaryotic and eukaryotic cells.
b. List and describe the basic function of three organelles.
c. Describe how these organelles work together to allow the
animal cell to function.
MC Question:
The endomembrane system is a complicated system involving
multiple organelles. Which of the following correctly describes a
the movement through this system of a protein that functions
best in the ER?
A. The mRNA is synthesized in the ER, translated on a free
ribosome to the Golgi, and then a transport vesicle carries the
mRNA back to the ER for modification. The mRNA is then sent
to the nucleus.
B. The mRNA is synthesized in the Golgi, is translated on a free
ribosome to the ER for modification, and then a transport
vesicle carries the mRNA back to the Golgi.
C. The mRNA is synthesized in the nucleus, is translated on a
free ribosome, then is sent to the ER and modified. A
transport vesicle carries the protein to the Golgi apparatus.
After modification, another transport vesicle carries the
protein back to the ER.
D. The mRNA is synthesized in the nucleus, is translated on a
bound ribosome, then is sent to the ER and modified. A
transport vesicle carries the protein to the Golgi apparatus.
After modification in the Golgi, another transport vesicle
carries the protein back to the ER.
The question requires background about the difference
between bound and free ribosomes, the functions of each
organelle in the endomembrane system, and the relationship
between the different organelles in the system. First, the
student must understand that the order of the
endomembrane system, with the specified protein from the
question, is: nucleus, ER, Golgi, back to the ER (since the
protein functions best in the ER). This eliminates A and B.
Between C and D, D is the only answer choice that has the
correct order and mentions a bound ribosome. Understanding
that this protein requires a bound ribosome is important
because bound ribosomes are attached to the rough ER.
a. A eukaryotic cell has membrane-enclosed organelles, the
largest of which is usually the nucleus. A prokaryotic cell
is usually smaller and does not contain a nucleus or
other membrane-enclosed organelles. Prokaryotes
contain a single circular chromosome, while eukaryotes
contain multiple linear chromosomes.
b. Three animal cell organelles are the Golgi apparatus, the
nucleus, and the ER. The Golgi apparatus, consisting of a
series of flattened membrane sacs (called cisternae),
synthesizes and packages small molecules for transport
in vesicles, and produces lysosomes. The nucleus
includes the nuclear envelope, the nucleolus, and
chromatin, and is the information center of the cell. The
ER consists of a smooth and a rough ER. The rough ER
gets its name from its surface containing ribosomes
(small structures containing rRNA and protein) and is
where protein synthesis occurs and contributes to
intracellular transport. Ribosomes can be free ribosomes
(suspended in the cytosol) or bound ribosomes
(attached to the outside of the ER or nuclear envelope).
The smooth ER synthesizes lipids.
c. The nucleus houses the most of the cell’s DNA and the
ribosomes use information from the DNA to make
proteins. Vesicles move from the ER to the Golgi.
Vesicles form and leave Golgi, carrying specific proteins
to other locations or to the plasma membrane for
secretion. Vesicles also transport certain proteins back
to the ER. These vesicles give rise to lysosomes and
vacuoles. Lysosomes are then available for fusion with
another vesicle for digestion. Transport vesicles carry
proteins to the plasma membrane for secretion.
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
understandings and/or big ideas.
Explanation: Speciation is when a new species originates due to evolution. It is important to understand speciation because it is the basis for
biological diversity. Isolation by any means in a species causes what was once a single species to evolve and become two separate ones
that are unable to mate and/or reproduce with one another due to biological differences or not being in the same place or time when it is
possible to do so. This can also help scientists and researchers to understand the overall evolution of species and how they originated.
Two types of speciation include allopatric speciation and sympatric speciation. Allopatric speciation is when a geographic barrier
isolates a population and blocks gene flow, which is defined as additions or subtractions to a population's gene pool due to the
movement of fertile individuals or gametes. Examples of this type of speciation would be an emerging river separating a field or a
mountain being created and dividing a piece of land. Sympatric speciation is when intrinsic factors such as chromosomal changes or
non-random mating alter the gene flow. There is no geographic change whatsoever. Examples of this would include many plants such as
oats or cotton. Both of these ways can lead to new species being created due to the gene make-up of a certain species divide because of
environmental or internal changes. Natural selection favors the genes that produce the most favorable traits to help organisms survive in
a certain type of environment. Genetic drift is defined as unpredictable fluctuations in allele frequencies from one generation to the next
because of a population's finite size. This means that when allele frequencies shift, it can also lead to eventual speciation because what
traits are prevalent in a certain population can change due to genetic drift.
Multiple Choice Question: Which of the following is an accurate example of allopatric speciation?
A) A mutation causing longer digits on a salamander causes the divide between ground-dwelling salamanders and tree-dwelling salamanders.
B) Chimpanzees and humans have similar body proportions, so it is likely they share a common ancestor.
C) A lake splits into two separate bodies of water and the population of yellow perches divides and is unable to mate with each other
successfully.
D) Due to behavioral isolation, blue-footed boobies will not mate with red-footed boobies.
Learning Log/FRQ-style Question: Explain the difference between
gradualism and punctuated equilibrium in the context of speciation.
Use diagrams to enhance your answer. Which of the two models best
describes a species in which a change in appearance occurred all at
once?Is one model more likely to fit under sympatric speciation or
allopatric speciation? Explain your answer.
Images in slides from ib.bioninja.com.au and palaeos.com
Multiple Choice Question: Which of the following is an accurate example of allopatric speciation?
A) A mutation causing longer digits on a salamander causes the divide between ground-dwelling salamanders and tree-dwelling salamanders.
B) Chimpanzees and humans have similar body proportions, so it is likely they share a common ancestor.
C) A lake splits into two separate bodies of water and the population of yellow perches divides and is unable to mate with each other
successfully.
D) Due to behavioral isolation, blue-footed boobies will not mate with red-footed boobies.
✔
C is the correct answer because the population is affected by an environmental change that causes the two sides to evolve independently
of each other, which is what allopatric speciation is based off of. (Think “allo-” means “other,” so they evolve in another place.)
Learning Log/FRQ-style Question: Explain the difference between gradualism and punctuated equilibrium in the context of
speciation. Use diagrams to enhance your answer. Which of the two models best describes a species in which a change in
appearance occurred all at once? Explain how both models fit into allopatric speciation and sympatric speciation.
Gradualism and punctuated equilibrium have to do with the rate of speciation. Gradualism has to do with a species slowly evolving
over a long period of time in which slow changes take place from generation to generation. Each adaptation changes the
physiology of the organism and the organisms selected for that trait will survive, while the organism to do not have that trait
will not. This results in gradual, or slow, changes rather than a major change all at once. Punctuated equilibrium has to do with
a species experiencing a major change after a long period of stasis. Instead of small changes over time, a species will change
after it separates from the parent species, but will do so very little after that initial point.
The punctuated model best describes a species that has undergone a sudden morphological change
after a long time of staying the same. In allopatric speciation, the species that becomes
environmentally isolated but remains similar to the original population only changing
slightly over time would be gradualism. This would mean that neither population becomes
extremely morphologically different after separating at first. A species that experiences
allopatric speciation in a punctuated equilibrium model would be a population that is
divided, and one side of the population dramatically changes in the next generation in order
to accommodate the environmental factors and differences they experience. A species that
slowly changes over time and after many generations is unable to reproduce with others in
the original population would have experienced sympatric speciation in a gradualism model.
With the same type of speciation in a punctuated equilibrium model, one part of the
population would experience a dramatic morphological change that would break away from
the parent species. All of these situations would result in a new species entirely, whether that
new species is in the same or a different location, or if it took place over a long or short
period of time.
Learning Objective 1.32: The student is able to justify the selection of geological, physical, and chemical data that
reveals early Earth conditions.
Science Practice 4.1: The student can justify the selection of the kind of data needed to answer a particular scientific
question.
Explanation:
At Earth’s beginning, there was very little oxygen, and a lot of
water, methane, carbon monoxide, and carbon dioxide. There was no ozone
layer which led to high levels of UV radiation, and lots of meteorite
bombardment. There was a lot of lightening and volcanic activity. Through
absolute and relative dating of fossils and rocks, and the knowledge that the
environment was too hostile for life until 3.9 byo, we can conclude that the
origin of life occurred between 3.5 and 3.8 billion years ago. The oldest rocks
were found in Greenland 3.8 billion years ago, and the oldest fossils were
dated to 3.5 byo. In 1953, the Miller-Urvey experiment was conducted to see
if Earth favored reactions that formed organic compounds from inorganic
compounds, which was a hypothesis made in 1920 by Oparin and Haldane.
Through repeated experiments, they concluded that all monomers necessary
for life (amino acids, all the components of nucleotides, sugars, lipids, etc.)
could be formed from inorganic compounds. This gave evidence that living
matter can come from lifeless matter, and that this is how the earth was
formed since it started out with no living matter but had an abundance of
free energy and barely any oxygen. These monomers connected to make
polymers as Syndey Fox proved by dripping monomers onto hot sand, clay, or
rocks to see if they would connect. These connected monomers created
protienoids which are poly peptides created by abiotic means. These
protienoids gave way to protobionts which are abiotically produced molecules
surounded by a membrane. We believe that eukaryotes originated through
endosymbiosis which is when molecules absorb one another and live inside of
each other. This is proven by the similarities between bacteria and
mitochondria & chloroplasts. They both reproduce by binary fission, have
small, circular genomes, and very similar DNA sequences , along with many
others. Current endosymbiotic relatationships also provide evidence… it had
to start sometimes, so it could have been then. How similar all organisms DNA
sequences/amino acid composure is a sign that we all are evolved from one
organism and so we conclude that there is a common genetic code. There is
some evidence that RNA was the first genetic material because through
ribozymes, RNA can self replicate and the RNA molecules best suited for their
environment replicate their DNA and reproduce so natural selection has an
impact. The origin of photosynthesis tells us what the atmosphere was like
during early times because the cyanobacteria used to have a bacteria that
metabolized dihydrogen sulfide, and that bacteria mutated to use water.
Water was abundant in the atmosphere at that time so the cyanobacteria
used it in photosynthesis. The oxygen that was released from the
photosynthesis reacted with dissolved iron and formed oxide precipitate and
the saturated water was released into the atmosphere.
Multiple Choice:
Which of the following statements about the
conditions of Earth’s beginning and the scientific evidence that
proves that condition is TRUE?
(a) The cyanobacteria’s bacteria that metabolized dihyrogen
sulfide mutated to use water rather than dihydrogen sulfide,
which proves that the Earth’s atmosphere in early times had an
abundance of dihydrogen sulfide.
(b) The cyanobacteria’s bacteria that metabolized dihyrogen
sulfide mutated to use water rather than dihydrogen sulfide,
which proves that the Earth’s atmosphere in early times had an
abundance of water.
(c) The percent of common amino acids in all organisms proves
that the theory of evolution is invalid.
(d) Monomers combined to make polymers which indicates that
there were great amounts of volcanic activity in Earth’s early
years.
FRQ: Explain the process of the origin of life on Earth and the
scientific evidence that supports these theories. Begin with no
life, and end with the formation of eukaryotes. Make sure that
you include information about how natural selection contributed
and cite the names of any scientists who contributed
experimental data to help solidify this theory.
FRQ Answer: The Miller-Urvey experiment was conducted to see if Earth
Answer Key
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Multiple Choice Question and Answer:
Which of the following statements about the
conditions of Earth’s beginning and the scientific
evidence that proves that condition is TRUE?
(a) The cyanobacteria’s bacteria that metabolized
dihyrogen sulfide mutated to use water rather than
dihydrogen sulfide, which proves that the Earth’s
atmosphere in early times had an abundance of
dihydrogen sulfide.
(b) The cyanobacteria’s bacteria that metabolized
dihyrogen sulfide mutated to use water rather
than dihydrogen sulfide, which proves that the
Earth’s atmosphere in early times had an
abundance of water.
(c) The percent of common amino acids in all
organisms proves that the theory of evolution is
invalid.
(d) Monomers combined to make polymers which
indicates that there were great amounts of volcanic
activity in Earth’s early years.
B is the correct answer. The other options are all wrong.
favored reactions that formed organic compounds from inorganic
compounds, which was a hypothesis made earlier by Oparin and Haldane.
Through repeated experiments, they concluded that all monomers necessary
for life (amino acids, all the components of nucleotides, sugars, lipids, etc.)
could be formed from inorganic compounds. This gave evidence that living
matter can come from lifeless matter, and that this is how the earth was
formed since it started out with no living matter but had an abundance of
free energy and barely any oxygen. These monomers connected to make
polymers as Syndey Fox proved by dripping monomers onto hot sand, clay,
or rocks to see if they would connect. These connected monomers created
protienoids which are poly peptides created by abiotic means. These
protienoids gave way to protobionts which are abiotically produced
molecules surounded by a membrane. Natural selection then comes in to
play because protobionts best suited for their enviroment could reproduce
and create others who were best suited for their enviroment. Coacervate is
a stable protobiont droplet that self assembles when a suspension of
macromolecules are shaken. Since we know that macromolecules can be
created in earth’s hostile enviroment due to the findings of Miller and Urvey,
we know that protobionts can also be formed. We believe that eukaryotes
originated through endosymbiosis which is when molecules absorb one
another and live inside of each other. This is proven by the similarities
between bacteria and mitochondria & chloroplasts. They both reproduce by
binary fission, have small, circular genomes, and very similar DNA sequences
, along with many others. Current endosymbiotic relatationships also proof
that it could have been responsible for forming eukaryotes so early because
it had to have started at some point in the history of the Earth, so why not in
the very beginning?
LO 4.5 The student is able to construct explanations based on scientific evidence as to how interactions of sub cellular
structures provide essential functions.
SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices.
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Explanation: In addition to the plasma membrane at its outer surface,
eukaryotic cells have extensive elaborately arranged internal membranes that
partition the cell into compartments. These compartments are the various
organelles that provide different local environments that facilitate specific
metabolic functions, so incompatible processes can go on simultaneously inside
the same cell. Ribosomes are particles made of ribosomal RNA and protein.
These two components of the ribosome interact to carry out protein synthesis
by translating the genetic material to produce specific polypeptides.
Ribosomes, however, are unlike most other organelles in the fact that they are
not enclosed in a membrane. Ribosomes can synthesize proteins in two
cytoplasmic locations, either suspended in the cytosol (free ribosomes) or
attached to the endoplasmic reticulum (bound ribosomes). The rough ER
containing the bound ribosomes serves to compartmentalize the cell and plays
a role in intracellular transport. The ER is formed by a network of membranous
sacs and tubes. The smooth ER allows for the synthesis of lipids, metabolism of
carbohydrates, and detoxification. The Golgi apparatus is a membrane bound
structure that consists of a series of flattened membrane sacs, known as
cisternae. The Golgi is involved in the synthesis and packaging of materials for
transport in vesicles and also allows for the production of lysosomes. The
mitochondria are the sites of cellular respiration and specialize in the
transformation of energy from sugars and other fuels to ATP. The mitochondria
is comprised of a double membrane that aid in the formation of the
concentration gradient that activates ATP synthase to produce ATP. The inner
membrane of the mitochondria is folded to allow for increased surface area to
aid in the mitochondria’s efficiency, these folds are known as cristae.
Chloroplasts are also specialized organelles found in algae and higher plants
that capture energy through photosynthesis. Chloroplasts have double
membranes that contain interconnected sacs called thylakoids. These
thylakoids are stacked to from grana and produce ATP and NADPH, which fuel
carbon fixing reactions of the Calvin cycle. Chloroplasts contain chlorophylls
that cause the green color of plants and function as the light trapping molecules
in photosynthesis. Lysosomes are membrane enclosed sacs that contain
hydrolytic enzymes that aid in intracellular digestion, recycling of organic cell
material and apoptosis. Vacuoles are membrane bound sacs that also play a
role in intracellular digestion and the release of cellular waste products.
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MC Question
A protein that is synthesized in the rough endoplasmic reticulum is
eventually incorporated into the cell’s plasma membrane. However,
a researcher observes that the protein that was integrated into the
membrane is slightly different than the protein made in the ER. The
protein was most likely altered in the _____ before being
incorporated.
A) Plasma membrane
B) lysosomes
C) Chloroplasts
D) Golgi Apparatus
FRQ Question
Imagine you are a scientist studying the liver, an organ that has the
main function of bile production along with blood filtration. You
have prepared a slide of liver cells ready to be observed under a
microscope for analysis. Hypothesize which organelle is most likely
to be highly concentrated within the cell and provide an
explanation as to why this organelle is abundant.
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MC Question
A protein that is synthesized in the rough endoplasmic reticulum is eventually incorporated into the cell’s plasma membrane. However, a
researcher observes that the protein that was integrated into the membrane is slightly different than the protein made in the ER. The protein
was most likely altered in the _____ before being incorporated.
A) Plasma membrane (membrane does not alter proteins and only contains the integral proteins already altered)
B) lysosomes (lysosomes specialize in digestion of intracellular materials)
C) Chloroplasts (Chloroplasts aid in energy transformation, not transformation of proteins)
D) Golgi Apparatus (Golgi Apparatus is involved in the alteration of proteins for transportation)
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FRQ Question
Imagine you are a scientist studying the liver, an organ that has the main function of bile production along with blood filtration. You have
prepared a slide of liver cells ready to be observed under a microscope for analysis. Hypothesize which organelle is most likely to be highly
concentrated within the cell and provide an explanation as to why this organelle is abundant.
•
The liver cell most likely contains a large concentration of Smooth Endoplasmic Reticulum. The smooth ER plays a vital role in detoxification
along with the synthesis of lipids and metabolism of carbohydrates. Within the liver the smooth ER provides the synthesis of enzymes that
help detoxify certain compounds such as alcohol. Another possibility for an abundant organelle is the high concentration of lysosomes.
Lysosomes also aid in the breakdown of toxic chemicals by containing the enzymes produced to aid in digestion or detoxification. Since the
liver is the site of detoxification and filtration, organelles specialized in the breakdown of toxic chemicals would be most abundant within the
cells.
LO 3.15- The student is able to explain deviations from Mendel’s model of the inheritance of traits.
SP 6.5- The student can evaluate alternative scientific explanations.
Explanation: Deviations from Mendel’s model of inheritance/ Punnett Square is shown through deviations from predicted ratios
like in the chi square technique (and Chi Square Lab with the corn kernels), sex-linked chromosomes, and genes that are not
passed through nucleic DNA. From the Chi Square lab we did during Unit 4, we counted the kernels on the corn and then
calculated the expected outcome of the number of kernels. The number of kernels counted and the number of kernels expected
were definitely different from one another and they never matched, but they were close. Genes also deviate from Mendel’s laws
by being linked a sex-linked genes on the sex chromosomes or having an extra chromosome like Trisomy 21/Down Syndrome. Sexlinked usually means that the allele is located on the X chromosome. Mothers and fathers pass an X-linked allele onto their sons or
daughters. If a sex-linked allele is recessive, daughters show the phenotype of the allele when they are homozygous and the sons
only show it when it is on their one X chromosome. More males are affected by sex linked-genes because they only need one
infected X chromosome to display that phenotype. Some examples of sex-linked alleles are Duchenne’s Muscular Dystrophy,
Hemophilia, and Color Blindness. There is also other types of DNA that are inherited that lie outside of Mendel’s rules because he
only focused on nuclear DNA. There is also DNA in the chloroplasts and the mitochondria. Chloroplasts and mitochondria are
randomly assorted to gametes and daughter cells; therefore, they do not follow Mendel’s Punnett Square and his rules of
Independent Assortment and Segregation. In animals, mitochondrial DNA is transmitted by egg so mitochondrial traits are
maternally inherited.
M.C. Question: A scientist finds that a group of rabbits that spawns multiple generations. Some have black Pedigree for Rabbits (multiple generations)
and white striped fur while the others have a normal solid coat of white. Determine which of these
statements are true with the pedigree of the rabbits provided. (See slide 2 for pedigree)
A) The traits for both the white and black striped fur and the solid coat of white fur are on the same
chromosome.
B) The black and white striped fur is a result of co-dominance.
C) The trait for black and white striped fur is a X-linked recessive trait.
Black- Striped Rabbits
White- Normal White
D) The trait for black and white striped fur is an autosomal recessive trait.
Coated Rabbits
E)There is not enough information to determine how the gene is inherited.
Learning Log/FRQ-style Question:
i. Explain Mendel’s Laws of Independent Assortment and Segregation and then explain TWO ways of inherited genes
diverging from Mendel’s predicted ratios. Justify your answer.
ii. Genetics are also determined by some alleles that are located on the sex chromosomes. Discuss sex-linked
transmission and then provide an example of a sex-linked trait.
Slide 1 of 2
ANSWER KEY-LO 3.15
A scientist finds that a group of rabbits that spawns multiple generations. Some have black and white striped fur while the others have a
normal solid coat of white. Determine which of these statements are true with the pedigree of the rabbits provided. (See slide 2 for
pedigree)
A) The traits for both the white and black striped fur and the solid coat of white fur are on the same chromosome.
B) The black and white striped fur is a result of co-dominance.
C) The trait for black and white striped fur is a X-linked recessive trait.
D) The trait for black and white striped fur is an autosomal recessive trait.
E)There is not enough information to determine how the gene is inherited.
Explanation: A is not correct because linked traits that are on the same chromosome are autosomal traits and are not sex-linked. B is not
correct because the black and white striped fur is not a result of codominance because in the population of bunnies the scientist has there are
no black bunnies in it so there are no black fur genes in the gene pool. C is correct because most of the sons of the parent bunnies get the black
and white striped fur because it is X-linked. It is recessive because the daughter bunnies need to have two of the black and white striped fur
gene on the X chromosome to show that version of fur. D is not correct because it is not an autosomal trait because it deviates from the Law of
Segregation.
i. Explain Mendel’s Laws of Independent Assortment and Segregation and then explain TWO ways of inherited genes diverging
from Mendel’s predicted ratios. Justify your answer.
ii. Genetics are also determined by some alleles that are located on the sex chromosomes. Discuss sex-linked transmission and
then provide an example of a sex-linked trait.
i. The Law of Independent Assortment discusses alleles aligning then separating independently during gamete formation when
genes for two traits are on homologous chromosomes. This takes place during Metaphase I. The Law of Segregation discusses that
each allele in a pair segregates into a different gamete during gamete formation. This takes place during Anaphase I. One way
inherited genes diverge from Mendel’s predicted ratios is by genes being on a sex chromosome. Sex-linked traits mostly occur in
males because most are on the X chromosome and only one infected X chromosome is needed for a male to be infected. Another
way genes differ from Mendel’s laws is there is always a chance for mutation in the genome during transcription and translation.
Mendel doesn’t take into account that part of gene can be changed during gene replication during gamete formation.
ii. Sex-linked transmission occurs during the deciding factor of whether a parent’s offspring is a boy or a girl. Sex-linked traits are
usually X-linked. Fathers pass X-linked allele to daughters (XX) and mothers pass on X-linked alleles to either a son or daughter. SRY
is the determining region of the Y. Without SRY, gonads develop into ovaries, and with SRY the gonads develop in the testes. If Xlinked alleles are recessive, females show phenotype when they are homozygous recessive. While males on the other hand show
the phenotype when hemizygous, making males more affected by sex-linked traits. An example of a sex-linked trait would be
Hemophilia, which is sex-linked recessive. If a person is a Hemophiliac, they do not produce enough protein needed for blood
Slide 2 of 2
clotting; therefore, there is no clotting.