Biology
Semester 2 Review
Mendel & Genetics
Review Powerpoint
• Gregor Mendel, the father of genetics.
Genetics is the study of Heredity.
Define Heredity.
• The passing on of traits from one generation to
the next.
• Where is the genetic information for traits
stored?
• In each individual’s DNA on chromosomes
containing many genes.
What did Mendel study to understand
inheritance?
• Common garden pea plants
• Why did he choose pea plants?
Give at least 3 reasons.
• 1--Fast growing with many offspring
• 2--Several traits—each had only two outcomes
• 3--Easy to cross pollinate—male and female
reproductive organs in each plant
What did Mendel call true
breeding?
• plants that come from a long line of plants that
show the same trait
• When he crossed two truebreeding plants with
opposite traits, he called this what?
• The “P” cross for Parental generation
• What did he get?
• The F1 generation that were 100% the
dominant trait
What was Mendel’s next step?
•
•
•
•
•
He crossed two F1 plants.
What results did he get?
The F2 generation
What interesting ratio did he find?
They were 3:1 (dominant to recessive)
What is the Law of Segregation?
• 1--Individuals must have two copies of genetic
information for every trait– one from each
parent
• 2—each copy is passed randomly
• 3—One of these copies (alleles) can mask the
expression of the other, ie. Dominant alleles
can mask recessive alleles when both are
present
What is the Law of
Independent Assortment?
• Alleles of different genes separate independently of
one another during gamete formation
• What does that mean?
• The allele a parent gives for one trait does not affect
what he/she gives for another trait so you can have
many different combinations of traits given to the egg
or sperm
What are alleles?
• Different forms of the same gene for a trait
• When an individual has two of the same allele,
the genotype is called..
• Homozygous
• When there are two different alleles, it is..
• Heterozygous
What is the difference between genotype and
phenotype?
• Genotype is
• the type of genes or alleles
• Phenotype is
• What is looks like--The physical appearance
of the organism
Monohybrid vs. Dihybrid
• Mono hybrid: a cross when there is just
one trait involved, ex.
• Height: Tt X tt
• Di hybrid: Two traits are involved, ex.
• The horse’s coat and gait are crossed
• FFGg X Ffgg
Autosomal vs. Sex-linked
• Autosomes are chromosomes not on the.. X or y
chromosomes
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•
•
•
•
•
Sex-linked characteristics are always on…
The X-chromosome
Give an example of a sex-linked condition
Hemophilia
Why does it occur more in males?
Males have only 1 X-chromosome so have a
better chance of having the condition.
Contrast a Punnett Square and a
Pedigree
• A Punnett Square is…
• a grid that predicts the types of possible
offspring from a cross
• A Pedigree is..
• A diagram that shows a family tree and
how traits pass from generation to
generation
Pedigree or Punnett Square?
Is this a monohybrid or dihybrid cross?
Modes of Dominance:
• 1--Complete dominance…
• One allele is completely dominant over the
recessive and the recessive is masked in a
heterozygous individual
• 2--Incomplete dominance..
• The dominant does not completely mask the
recessive and the heterozygous phenotype is a
blend of the two- an intermediate variation.
• There are three possible phenotypes.
More modes of inheritance
• 3-- Co dominance..
• More than one genotype is dominant and when two of
these are together, they form another phenotype
•
•
•
•
•
•
4– Multiple alleles..
These traits have 3 or more alleles
Example of both codominance and multiple alleles..
blood types. How many blood types are possible?
Four-- They are..
A, B, AB, and O
Modes of Inheritance cont.
• 5-- Polygenic Inheritance: traits that are..
• controlled by many genes.
• This makes many variations of color and
trait possible
• What are characteristics controlled by
multiple alleles?
• Human hair and eye color
Genetic Diseases:
• Sickle Cell Anemia causes..
• Abnormal hemoglobin molecules and poor circulation of
blood
• Cystic Fibrosis causes..
• Build up of mucus in lungs and organs
• Hemophilia- sex linked condition that causes
• Bleeding and inability to clot
• Huntington’s Disease causes..
• Deterioration of brain tissue and decreased muscle
control
DNA Structure
DNA Replication
Meiosis
DNA Structure
• Before the 1950’s, scientists had no idea
what DNA looked like or what it was made
of.
• Who were the researchers who came up
with the best model of DNA’s shape and
structure?
• Watson and Crick
• What shape best describes DNA?
• A Double Helix = two winding spirals
What is the monomer (or subunit)
that DNA is made of?
• The Nucleotide
• Each nucleotide has three parts: Name
them.
• 1. A Phosphate
• 2. A Deoxyribose (5-carbon sugar)
• 3. And a Nitrogen Base
• How many bases are there?
• 4-- Name them.
Nitrogen Bases
• G-C-A-T
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•
•
•
Guanine
Cytosine
Adenine
Thymine
How do these nitrogen bases
pair up?
• They are…
• Complementary. Define this.
• Each nitrogen base has a match and will
only pair up with that match.
• G only bonds with..
• C
• A only bonds with..
• T
• REMEMBER “G-CAT”
Notice how the complements fit together like
a puzzle.
DNA Structure
• The Ladder Analogy: How do
these parts look like a
ladder?
• What is the Backbone of the
ladder?
• The strong phosphate/sugar
sides.
• What make the rungs, or
steps, of the ladder?
• The nitrogen base pairs.
DNA contains a code.
Where is the code located?
• In the order of the nitrogen bases.
• Why do we say it is “universal”?
• Because this code is present in all living things but in a
different order.
• What sort of messages are carried by the code?
• The code is a recipe for making proteins which carry out
all the important work of cells that make life possible.
• Examples: building muscle tissue, digesting food, all
chemical reactions in the body.
What bonds hold the components of the
DNA together?
The bonds between the sugars and
phosphates are …
•
•
•
•
Covalent bonds
Weak or strong?
Strong
The bonds between the nitrogen bases
are…
• Hydrogen bonds
• Weak or strong?
• Weak
Now let’s talk about replication.
• What is replication?
• A process in which a copy
is made of the DNA strand.
• When in the cell cycle does
this happen?
• Before the cell can divide, it
needs to double its DNA.
This happens in the S
(synthesis phase) of
Interphase.
Name the steps in replication
including the enzymes needed
• STEP 1: Helicase breaks the hydrogen bonds between
the nitrogen bases. This “unzips” or unwinds DNA into
two strands. The nitrogen bases are now unpaired
because they are separated from their complements.
• STEP 2: DNA polymerase adds free nucleotides to the
unpaired bases and new bonds form
• STEP 3: DNA polymerase checks for and corrects errors
in the base pairing.
• END RESULT: Two identical molecules of DNA from the
original.
Why do we call this process
“semi-conservative”?
• Conservation= saving and recycling
• The original strands are re-used to make
two identical molecules.
• Each molecules will have a strand of
original DNA and a strand of new DNA.
• Now that replication has taken place, what
happens next?
• Cell division
What is Meiosis?
• a process of cell division in which a
reproductive cell divides into 4
haploid cells
• How is it different from Mitosis?
MITOSIS
Occurs in any type
of body cell except
reproductive.
Results in diploid
cells
Has 4 phases PMAT
End product= 2
identical cells
MEIOSIS
Occurs in
reproductive cells
only.
Results in Haploid
cells.
Has 8 phases with
two separate cell
divisions.
End product= 4 cells
that are genetically
unique
Distinguish between: homologous chromosomes,
sister chromatids, and tetrads.
• Homologous chromosomes: chromosomes that are the
same kind—in size, shape, and types of genetic info.
They are not necessarily identical.
•
EXAMPLE(One Homologue may carry the blue eye color gene, while the
other carries the brown eye color gene, but BOTH chromosomes carry an
eye color gene)
• Sister chromatids: two matching strands of DNA joined
by a centromere
• Tetrads: 4 chromosomes in Metaphase I
• Two homologous pairs, side by side.
Name two sources of genetic variation
in Meiosis.
• 1. Crossing over:
• 2. Random Alignment of Homologous
chromosomes
What is crossing over?
• The exchange of genetic material between
two homologous chromosomes. This
occurs during..
• Prophase I.
What is the Random Alignment of
Homologous Chromosomes?
• The random order the homologous chromosomes line
up in, side by side, on the equator during Metaphase I.
• How is this “Independent Assortment”?
• (Any one with any other one)
• The homologous chromosomes can be on the left or
right of the midline.
• The combination of chromosomes on the left will be very
different than the combination on the right which results
in haploid cells at the end of Meiosis that are very
different.
Meiosis can be divided into two cell
divisions
Meiosis I separates the Homologous
Chromosomes
At the end, two cells go on to Prophase II
Meiosis I: Separate the Homologues
Meiosis II
• Meiosis II separates the sister chromotids.
• The end result is 4 haploid cells
Compare: Haploid vs. Diploid
DIPLOID
Somatic cells
2 sets of DNA
MOM + DAD
Identical cells
HAPLOID
reproductive cells
1 set of DNA
combination
each is unique
Reproductive cells begin as:
• Germ cells (cells that may germinate, like
seeds, into a new organism)
• When they are haploid cells they are
called..
• Gametes. Give examples of gametes:
• Sperm and egg cells are gametes
• When sperm and egg join, the result is..
• a zygote (a fertilized egg)
Why is it important for Meiosis to
produce haploid cells?
• So that when sperm and egg join, the
resulting zygote will have 2 sets of DNA
and not 4.
• Remember the law of segregation?
• “have 2, pass 1”.
• Meiosis allows for the passing of 1 set of
DNA to the offspring
The zygote becomes…
A baby-Also known as “the offspring”
"You're unique. Just like
everyone else..." -- Anon.
• Explain how this quote relates to what
we’ve learned about DNA.
• Every living thing has a genetic code in the
sequence of nitrogen bases.
• You and every other organism are unique
because there are differences inherited;
These variations come from Meiosis and
sexual reproduction: the reshuffling of
genetic information in millions of
combinations.
Protein Synthesis
PROTEIN SYNTHESIS
• What does DNA’s code do?
– Directs Protein Making
• DNA’s code contains the instructions to
make proteins!
The process of making RNA
from DNA is called…
• TRANSCRIPTION= the process in which
the coded message in DNA is rewritten
into mRNA. (TranSCRIBE means
reWRITE)
Where does transcription take
place?
• In the nucleus
Why does DNA need to be
transcribed into RNA?
• DNA cannot leave the nucleus. The
membrane is impermeable to DNA.
• RNA can leave the nucleus. It is singlestranded and the membrane is permeable
to it.
Give the Differences between DNA
and RNA
• Nitrogen base
• Type of sugar
• Number of strands
DNA
RNA
What kind of nitrogen bases?
Thymine
Uracil
What kind of sugar?
Deoxyribose
Ribose
What shape?
Double strand
Single strand
How many kinds of RNA are there?
• THREE:
• Name them.
1. Ribosomal
2. Transfer
3. Messenger
What are their functions?
Messenger RNA
• Brings the coded message from DNA to
the ribosome
Transfer RNA
• Carries or transfers amino acids to the
ribosomes according to the
codon/anticodon arrangement.
What is Ribosomal RNA?
• what a ribosome is made of, along with
protein
What is TRANSLATION?
• The process of TRANSLATING the
message from mRNA into a different
language form = the chain of amino acids
that make up a protein.
Where does translation take
place?
Find the location on the
diagram on the next slide.
At the ribosome in
the cytoplasm of the
cell.
The 3 letter code on the mRNA
• CODON
The 3 letter code on tRNA
• anticodon
Where on the mRNA does
translation start?
When it reads a START Codon.
AUG is the start codon for all
proteins.
BIG IDEA!
How does protein synthesis
result in gene expression?
Genes carry the DNA code
which tells the ribosomes what
proteins to make.
These proteins create the traits
that are seen in the organism.
1.Transcribe this DNA strand into
mRNA
• AATACCGTGGATCGATC
• UUAUGGAUCCUAGCUAG
2. Using the table, Translate
the mRNA into the amino acid
sequence to make a protein.
Nice work!
• If you got …
• Met-Ala-Pro-Ser-Stop
What is a Mutation?
• A change in the DNA
What can cause a mutation?
• 1. Chemicals in the environment- mutagens like
pesticides
•
• 2. Energy exposure- ultraviolet radiation from
the sun, x-rays, other sources of radiation
• 3. Cellular mistakes made during replication
What are the Types of Mutations?
Point and Frameshift Mutation
These can cause changes at 1
codon point or shift the frame
so that every codon after the
mutation is affected.
• What is an example of a
Point Mutation?
• a Substitution.. This happens
when one nitrogen base in the
code is changed or substituted
for the correct one.
• 2. What are Frameshift
mutations?
• insertions or deletions that shift
the frame and alter the codons
from the error to the end of the
mRNA
Evolution
Evolution Review
Who’s the man?
Charles Darwin
What did Darwin observe on his
Journey on the HMS Beagle?
• Many different species of plant and animal
life
• Fossils of extinct animals
How did Darwin explain the
differences in the Galapagos
finches?
He proposed that the 13 different
finches had come from a…
• Common ancestor
What is a population?
• A group of one species of organism in a
specific geographical area that can
interbreed.
Evolution is a..
• Well-accepted theory of how organisms
have changed over time by natural
selection.
• Darwin based his ideas on:
• 1. observations of nature
• 2. Malthus’s theory about exponential
population growth
• 3. his experience breeding animals
Tenets of Evolution
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•
•
•
•
Populations have the potential to grow…
exponentially
They don’t because..
resources are limited
There are differences in individuals (genetic
variation)
• These differences can help some individuals
survive better than others
• Those that survive longer pass more of their
genes on to the next generation.
What is Natural Selection?
• The idea that individuals with traits that
make them well-suited to the
environment will survive and reproduce,
passing on their genes, at a higher rate
than less suited individuals.
• This will cause a change in frequency of
alleles in the population
Process of becoming better suited
to the environment is called..
• Adaptation
• What does natural selection act on?
• On populations over many generations.
What is needed for natural
selection to occur?
• Genetic variation (differences) in the
individuals must exist
• Otherwise all members of the population
would have the same advantage for
survival
What are 4 sources of
genetic variation?
• 1. Mutations- errors in base pairs caused by mutagens,
energy exposure, or errors in replication
• 2. Meiosis- two events occur:
• Random alignment
• Crossing over
 3. Immigration- new genes come into population
 4. Sexual Reproduction- combining the alleles of
mother and father
What 4 processes change allelic
frequency?
• 1. Natural Selection- environment
determines which traits will survive and be
passed on
• 2. Artificial Selection (breeding)- humans
decide which traits will be bred for
• 3. Gene Flow
• 4. Genetic Drift
Gene Flow
• Genes moving in and out of a population
• Give two examples:
• 1. immigration– new individuals move in
• 2. emigration- individuals move out
Genetic Drift
• This is a ___________change in allelic
frequency that is due to chance.. Not
environmental pressure.
• Answer= RANDOM
Gradualism vs
Punctuated Equilibrium
• Hypothesis that evolution occurs in short
bursts of rapid change, then periods of no
change is…
• Punctuated equilibrium
• Hypothesis that evolution occurs gradually
at a slow, constant rate is..
• Gradualism
What has to happen for a new
species to become established?
• First, Reproductive Isolation from the
original group
• Example: a flock of birds gets separated and blown
toward an island by a storm
• They are now isolated from their original group on
another island.
• Over time, in 2 different environments, they become
more and more different
When does speciation occur?
• When they can no longer interbreed with
the original group of birds
• A speciation event=
• A new species
When a group of organisms starts
a new colony, it is called..
• The Founder Effect
What is a genetic bottleneck?
• This happens when a natural disaster
(earthquake, volcano, etc) kills off a group
of the original population, and the allelic
frequencies change (genes are lost). Now
the group has different amounts of the
alleles for certain traits.
When 2 species become …
• More different, it’s called…
• Divergence (diverse=different)
• More alike, it’s called…
• Convergence (converge=coming together)
What are Vestigial structures?
• Those anatomical features that no longer
have a purpose
• Examples: in whales…
• They have small back limbs, inherited
from an ancestor that moved on land.
See next slide.
What are Homologous structures?
• Similar structures in different species that
suggest that they have a common
ancestor
• Example: the forearm of many vertebrates
(humans, bats, alligators, etc) have similar
bones. See next slide.
Contrast:
Scientific theory,
law, and hypothesis
• Theory= an explanation of how a natural
phenomenon occurs
• Law= describes a phenomenon
(mathematically)
• Hypothesis= a prediction based on
research and prior knowledge
Ecology Review
Ecology is the study of..
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•
•
•
•
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Ecosystems.
Ecosystems include both...
Biotic and Abiotic Factors
Biotic factors are the
living components of ecosystems like..
Plants, animals, bacteria, fungi
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•
•
•
•
•
Abiotic factors are the
nonliving components like...
1.climate/weather patterns
2. soil, water, minerals,
3. land forms and features
4. amount of sunlight
Define population.
• a population is a group of one
species living in a specific area.
• What is a community?
• a community is groups of different
species living in one habitat
• a habitat is the place where a
community of organisms lives
Name the types of organisms
in a food chain
1. Producers: (where do they get energy?)
from the sun—these are organisms that use
photosynthesis to convert the sun’s energy
2. Consumers:
organisms that eat or use other organisms to
obtain energy
3. Decomposers:
Organisms that breakdown plants and dead
animals putting nutrients back into the environment;
like bacteria and fungi
Types of Consumers:
• 1. Herbivores-- eat plants
• 2. Carnivores-- eat meat (other animals)
• 3. Omnivores-- eat both plants and
animals
• 4. Detrivores-- eat dead organisms, ie.
scavengers
Trophic Levels
How much energy moves from
one trophic level to the next?
• only 10% of the energy from one trophic
level moves up to the next
• 90% of the energy is lost -- given off as
heat or wasted energy
Biogeochemical Cycles:
The Water Cycle
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•
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1. liquid water becomes vapor=
EVAPORATION
2. water vapor becomes clouds=
CONDENSATION
3. rain, sleet, snow, hail=
PRECIPITATION
4. water comes out of leaves of plants=
TRANSPIRATION
Water Cycle continued..
• 5. water drains into streams, rivers,
oceans=
• RUN-OFF
• 6. water filters into the soil and goes
through to the ground water=
• PERCOLATION
• 7. water vapor exhaled by animals=
• RESPIRATION
• 8. water taken in by roots=
• ABSORPTION
THE CARBON CYCLE
What are the only organisms that use CO2?
• Plants ..They take in Carbon (CO2) during
PHOTOSYNTHESIS
• What gives off Carbon Dioxide?
• We do, when we exhale...
during RESPIRATION
• We do, when we burn fuel....
COMBUSTION
Other sources of carbon in the
air, water, or soil
• Geologic activity like.. volcanoes
• EROSION --water/wind dissolves
limestone releasing CO2
• Remember --plants are the only things that
can remove CO2
What is the Greenhouse Effect?
• The heat trapping ability of some gases in
the atmosphere.
• This can be compared to the way glass
traps heat in a greenhouse, or an
insulating blanket
• This is a good thing for us, because it
keeps the earth’s surface temperature
liveable
• What is happening while greenhouse
gases, like CO2, are increasing?
Global Warming
• This refers to the
increase of the
average
temperature of the
earth.
• The earth's
temperature has
been rising for the
last 50 yrs.
Film: One Degree Factor
• How did one degree rise in temperature
affect the caribou?
• more mosquitos, longer mosquito season
• drove caribou higher up where there was
not as much food
• more rain, freezing on top the snow
• made finding food difficult, made crust on
the snow that cut their legs
Film (cont):
It is a Global Problem
(affects everyone):
• How can a drought in Africa affect children
and ocean in Trinidad?
• The drought caused the lake in Africa to dry
up. Dust from the lake was blown by the
winds to the Caribbean Sea.
• Caused increase in Asthma and Sea Fan
disease.
Is the hole in the ozone layer
part of global warming?
• NO.
• It is another example of a man-made impact on the
environment, though.
• What caused the decrease of concentration of ozone (O3)
in the atmosphere?
• Use of CFC's (chlorofluorocarbons) in spray cans,
refrigerators, air conditioners, etc.
• These chemicals destroy molecules of ozone.
• What is so bad about a decrease in concentration of
ozone?
• Ozone protects us from UV radiation, so because the
concentration of ozone decreased, skin cancer rates went
up.
Here's the good news:
• We changed what
we were doing by
finding alternatives
to CFC's,
• and the hole in the
ozone layer is
becoming smaller!
The Nitrogen Cycle
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•
•
•
•
•
Why do living things need nitrogen?
To make amino acids and nucleic acids to build..
Proteins, RNA, DNA
How much of the atmosphere is nitrogen?
78%
Atmospheric nitrogen, N2 is unusable by plants
and animals
How is nitrogen in the
atmospheric made usable?
• Nitrogen Fixing bacteria convert N2 into
usable products so plants can absorb it.
• What are the names of nitrogen fixing
bacteria?
• In soil, it’s…
• Rhizobium bacteria
• In water, it’s…
• Cyanobacteria
Where do living things get their
nitrogen?
•
•
•
•
How do plants get nitrogen?
from the soil (they absorb it through roots)
How do animals get nitrogen?
by eating other plants or animals
Some Nitrogen Cycle Terms:
• Nitrogen Fixation= bacteria turns N2 gas
into ammonia
• Ammonification= bacteria in soil convert
organic material to NH3
• Nitrification= ammonia into nitrites/nitrates
• Assimilation=plant roots take in nitrates
• Denitrification=bacteria turns nitrates into
nitrogen gas
Weather Patterns
• Explain the Coriolis Effect:
• because of the rotation of the earth, winds and
weather seem to curve to the right; this is the reason
our storms come from the Southwest and move in a
Northeast direction
• Explain the Mountain Effect:
• all the precipitation is dumped on the windward side
of the mountain, so the leeward side is dry; for
example.. Denver, CO has very little snow. It is on the
east side of the Rockies. Most of the ski resorts in
Colorado are on the west side of the Rockies.
Some Terrestrial Biomes:
• Tundra: cold, permafrost, little rainfall,
caribou, foxes that have thick fur- white in
winter
• Taiga: cold, two seasons- summer and winter,
moose, bear, lynx, hibernate in winter
• Temperate, deciduous forest: moderate rain,
deer, rabbits, squirrels, birds,
• Rainforest: high amount of rainfall, great
diversity of plants, animals
• Desert: hot, dry, little rain, animals and plants
adapted to heat and little water
Which biome has the greatest
amount of biodiversity (different
plants and animals)?
• The Tropical Rainforest due to its high
amount of rainfall, and the amount of
sunlight it gets year round.
Symbiosis- relationships
between organisms in habitats
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•
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1. Predation- one organism eats another for food
(+,-) predator benefits, prey is harmed
2. Parasitism- one organism lives off another.
(-,+) parasite benefits, host is harmed
3. Mutualism(+,+) both benefit
4. Commensalism(+, 0) one benefits, the other is neither harmed nor benefitted
5. Competition- two organism compete for resources
(- ,- ) both are harmed
Which is it?
• A sucker fish that lives on a shark. The fish removes
fungus from the shark by feeding on it.....
• That is Mutualism because both benefit
• A tick sucks the blood from a deer...
• That is Parasitism because the deer is harmed
• A bird that lives in a hole in a tree is...
• Commensalism (the tree is neither harmed nor
helped but the bird gets shelter)
• Squirrels and Cardinals both eat sunflower seeds..
• is an example of Competition for the same food
source.
Competitive Exclusion
Two species cannot exist in the same space
so they must each find their own “niche”.
If one of the species is more successful and
eliminates the other, it is called..
Competitive exclusion
Two species can avoid competition by
finding different niches in an ecosystem.
What is a niche?
• The job an organism has in its habitat,
its pattern of living—
• the resources it uses, where it feeds, finds shelter,
temperature requirements, etc.
• fundamental niche:
• the part of the habitat the organism could occupy if
there were no competition
• realized niche:
• the part of the habitat it actually occupies (in reality)
Population Growth
• Populations that grow unchecked will grow..
• Exponentially
• They don't because they are limited by
various factors like..
• Amount of resources, diseases, predators
• The size that a population is limited to by
the environment is called its:
• CARRYING CAPACITY
POPULATION
LIMITING FACTORS:
• When factors are affected by the size of the
population they are:
• DENSITY DEPENDENT FACTORS
• Ex. food, shelter, water, etc.
• When factors are not affected by the size of
the population, they are:
• DENSITY INDEPENDENT FACTORS
• Ex. weather, climate, disease, etc.
What is SUCCESSION?
• The changes in an ecosystem over time.
• What is Primary (1st) succession?
• living things coming into an area where
there was no life before
• ex. a glacier melts exposing soil after 100's
of 1000's of years
• Secondary (2nd) succession is..
• new life in an area that had life before
• ex. forest after a forest fire
What are Pioneer Species?
• organisms that are the first to live in an
area; for example..
• Small, fast growing plants
• Grasses, weeds, mosses and lichen are the
first plants that grow in an area.
Biotechnology
Combining Life Science
and Technology
What is Genetic Engineering?
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•
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Process of manipulating genes for a
practical purpose. Making recombinant
DNA is a process used for this.
Examples of Genetic engineering:
Making proteins/vaccines to treat
diseases
•Genetically modified plants-that are created to be more
drought resistant or grow bigger.
What is Recombinant DNA?
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DNA from 2 or more different species combined.
Why combine DNA?
In this way, human genes can be inserted into
other organism.. and that organism can then make
human proteins for medical uses,
This is called a transgenic organism. Example...
Bacteria with the insulin gene can make human
insulin for treatment of diabetes
What is a Vector?
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Anything that is used to transfer DNA
into a host cell.
What are three types of vectors?
Plasmid, Virus, Yeast
What is a Plasmid?
A circular piece of DNA from bacteria
that can replicate independently.
Give the steps to making
Recombinant DNA.
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1. Identify the gene of interest-- a gene sequence
that codes for a protein for example.
2. Cut the DNA with...
Restriction enzymes
3. Cut vector DNA with same restriction enzymes
4. Insert gene of interest into vector DNA
5. Sticky ends allow gene to attach with help of
enzyme DNA ligase
6. Insert recombinant DNA into a host cell
How do Restriction Enzymes
cut DNA?
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They recognize a pattern in the genetic
code (order of nitrogen bases). This
pattern is..
A Palindrome sequence. It is the
same...
Backwards as forwards
ex. R-A-C-E-C-A-R
Restriction enzymes always cut at the
same specific base sequence and
leave sticky ends
What are sticky ends?
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The unpaired bases left in the specific
sequence
They will attract their complementary
bases and allow the gene of interest to
combine with the plasmid.
What is PCR?
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Polymerase Chain Reaction
What is it used for?
It is used to copy a DNA sample so that there is
more of it for testing.
What natural process does it mimic?
DNA Replication
Example: Crime scene may only yield a small
amount of skin cells or a drop of blood. PCR
replicates the sample so that they can complete
many tests on the sample.
What are the Steps to PCR?
1. Denaturing- Raise the temperature (~95 C) to
break hydrogen bonds of DNA, separating the
strands to reveal unpaired bases.
2. Annealing- Lower the temperature (~54 C) to add
primers (short segments of DNA).
3. Extension- Raise the temperature (~72 C) to an
optimum range for Taq polymerase to add free
nucleotides to the original strand.
• Result is two copies of the original DNA
• DNA is doubled every 2 minutes. In a few hours
millions of copies can be made.
DNA Fingerprinting
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Identification method using DNA
Is not the same as taking a print from the fingers.
What does DNA Fingerprinting produce?
It produces a pattern of dark bands that is unique
for each individual.
What is DNA Fingerprinting used for?
1. Criminal cases-- identifying crime scene DNA
2. Paternity cases-- finding out who the parents of a
child are
3. Sorting Recombinant vs. Nonrecombinant DNA
What are the steps to making
a DNA fingerprint?
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1. Obtain a biological sample from..
Blood, semen, saliva, skin cells
2. Make several copies of the DNA
sample using PCR
3. Cut the DNA into segments using...
Restriction enzymes
4. Use gel electrophoresis to sort the
sections of DNA by size
What is gel electrophoresis?
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A technique for measuring DNA
segments using a gel and electricity to
separate DNA according to size.
Explain how
gel electrophoresis works.
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DNA samples are loaded into wells in
the gel using a...
Micropipette
Electrical current is turned on, allowing
the DNA to move through the gel
toward the..
Positive end of the gel because…
DNA has a negative charge.
How are the bands created?
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DNA segments travel different distances
depending on their...
Size (length)
Describe how long vs. short pieces
move.
Longer segments move shorter
distances because they move more
slowly through the gel
Shorter segments move fastest and
go... the greatest distance away from
the start.
What is responsible for the
different sized DNA fragments?
• Non-coding repeated base sequences
between genes are responsible for the
different sized DNA fragments (RFLP’s)
What is the gel made of?
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Agarose powder and buffer solution
What does the gel have that makes it
good for separating the DNA?
There are holes (spaces) in the gel that
the segments have to go through (like a
filter)
Why is buffer used?
To conduct electricity through the gel
What is a clone?
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An organism that is an exact copy
(genetically identical) of another
organism
What is a method used to transfer one
organism's DNA into an enucleated
host cell to create a clone?
Somatic Cell Nuclear Transfer
List the steps to:
Somatic Cell Nuclear Transfer
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1. Remove nucleus from somatic cell
2. Remove and discard nucleus from an
egg cell..
3. Put somatic cell nucleus into
enucleated (empty) egg cell.
4. Allow time for DNA to adjust and
reprogram
5. Stimulate cell division electrically or
chemically
6. Put divided cell embryo into a
surrogate mother.
When the new organism is born,
what will it be a clone of?
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The donor organism. The one that gave
the somatic cell nucleus.
What is therapeutic cloning?
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Creating tissue from a patient's DNA
that is an exact copy of the patient in
order to grow organs that can be
transplanted in the patient that his body
will not reject.
Example.. take liver cells and stimulate
them to grow in the lab in order to make
a new liver to replace the patient's
damaged one.
Define Stem Cells.
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Stem cells are cells that haven't been
programmed yet-- they do not have jobs
in the body, but could become many
different kinds of cells.
There are 3 kinds:
Totipotent, Pluripotent, Multipotent
If you remember TPM “The Perfect
Man” it will help you remember the
order of Best to Least useful.
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Differentiate between the
types of stem cells
Totipotent—Can become any kind of
cell They are found in …
early embryos
Pluripotent—They can become almost
any type of cell and are found in..
Late embryos and early fetuses
Multipotent—can only become certain
kinds of cells and are found in...
Adult blood, bone marrow and in
umbilical cords
What are the medical uses
of stem cells?
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Treat paralysis
Treat brain injuries and strokes
Treat leukemia (bone marrow cells)
Treat diabetes (pancreas cells so that
pancreas will begin producing insulin)
Digestion and Circulation
Digestive System
• What is Mastication?
Chewing and moistening of food with saliva.
• What prevents food from going into the
trachea?
Epiglottis
• What is Peristalsis?
Wave like contractions of the esophagus that
moves the bolus from the mouth to the
stomach.
Digestive System in the
Human Body
Stomach
• Food enters the stomach through cardiac sphincter.
• Peristaltic waves help digest food.
• Chyme moves from the stomach into the small
intestine through the pyloric sphincter.
The Stomach and Accessory
Digestive Organs
Small Intestine
• The duodenum (top of S.I.) gets secretions from the
liver, pancreas and gallbladder.
• What are villi?
Fingerlike protrusions that increase the surface area of the
small intestines.
• Nutrients (broken down food biomolecules) are
absorbed by villi on the walls of small intestine.
Villi in the Small Intestine
Cross Section of the Small
Intestine
Large Intestine
• Large Intestine (Colon). (~3.3 ft. long but 3x
wide).
• No digestion in the L.I.
• Water and ions are absorbed in the L.I.
• Wastes pass to the end of the colon, the rectum
and expelled by the anus.
Enzymes of Digestion
• Carbohydrates
– Broken down by Salivary Amylase from the
Salivary Glands in the mouth.
– Broken down further by Pancreatic Amylase
from the pancreas in the duodenum.
Enzymes of Digestion
• Proteins
– Denatured by HCL in the stomach
– Broken down by Pepsin in the stomach
– Broken down into Amino Acids by Trypsin
from the pancreas in the duodenum.
Digestion of Lipids
• Lipids
– Lipids are separated by bile from the liver in the
duodenum.
– Lipids are then broken down by Lipase
• Lipids are non polar. Lipase is polar. Bile is
polar and non polar so the two can mix.
• Bile is produced by the liver and stored in the
gallbladder.
Circulatory System
• Transports:
• Oxygen, Nutrients, Hormones,
• Removes
• Carbon Dioxide, Metabolic Wastes
Blood is Red. Always.
Oxygenated Blood
Deoxygenated Blood
Components of Blood
• Plasma
– Water and dissolved nutrients
• Red Blood Cells (erythrocytes)
– Carries oxygen
• White Blood Cells (leukocytes)
– Fights infection
• Platelets
– Helps in the clotting of blood
Components of Blood
– What is the oxygen carrying protein in red blood
cells?
Hemoglobin
Heart
• Muscular pump for blood to circulate.
– 2 atria- chambers that receive blood
– 2 ventricles- chambers that pump blood away
• Deoxygenated blood returned to the right side.
• Oxygenated pumped from the left side.
Blood Vessels
• Arteries
– Carries blood AWAY from the heart.
• Veins
– Carries blood TO the heart
• Capillaries
– tiny branches of blood vessels
– takes blood from arteries to each cell and back to
veins
Circulation in the Human Body
Path of Blood Flow Through
the Heart
O2 and CO2
in the Blood
THE END-- Best of luck!