Biology B Final Review ANSWERS
During which phase of meiosis do homologous chromosomes align as tetrads in the middle of the spindle?
A. prophase I
C. metaphase I
B. prophase II
D. metaphase II
The tall allele, T, is dominant to the short allele, t, in Mendel’s pea plants. You examine a pea plant what
exhibits the tall phenotype. What is its genotype?
A. Tt
C. tt
B. TT
D. A and B are both possible.
Which was concluded by Mendel as a result of his genetic research?
A. Factors for different traits are inherited together as a matched pair.
B. Polyploidy can be beneficial in agriculture.
C. Factors for different traits are inherited independently of one another.
D. Meiosis occurs in two steps, meiosis I and meiosis II.
After performing a monohybrid cross, it is important to analyze the results with a Punnett square. What does
each box in a Punnett square represent?
A. possible phenotype
C. one individual
B. possible genotype
D. two possible genotypes
What process is taking place in the illustration shown below?
A. fertilization
B. prophase II
C. polyploidy
D. crossing over
Which statement best explains the significance of meiosis in helping to maintain continuation of a species?
A. Meiosis produces eggs and sperm that are alike.
B. Meiosis provides for chromosomal variation in the gametes produced by an organism.
C. Equal numbers of eggs and sperm are produced by meiosis.
D. The gametes produced by meiosis ensure the continuation of any
A researcher crosses the F1 generation of two snapdragon plants. According to this information and the diagram
below, what is the ratio of their offspring (F2)?
A. 0 red; 4 pink; 0 white
B. 1 red; 2 pink; 1 white
A molecule of DNA is made up of__________.
A. amino acids and proteins
B. ATP and enzymes
C. 3 red; 0 pink; 1 white
D. 4 red; 0 pink; 0 white
C. paired nucleotides
D. receptor enzymes
If the structure of DNA were likened to a ladder, what would make up the “supporting structure” (not the
“rungs”) of the ladder?
A. amino acids and sugars
C. nucleotide bases, including uracil
B. nucleotide bases, including thymine
D. sugar-phosphate molecules
The diagram to the right shows a portion of a DNA molecule. The letters in the
diagram represent the four bases: adenine (A), thymine (T), guanine (G), and
cytosine (C). Which sequence of bases do the question marks represent?
A. C-A-C
C. G-A-C
B. G-C-A
D. T-C-A
Which do DNA and RNA have in common?
A. Both are double stranded.
B. Both contain ribose molecules.
C. Both contain phosphate groups.
D. Both contain uracil.
Proteins are chains of amino acids bonded together. Which is the correct sequence for making proteins?
A. Information in DNA is formed into protein directly.
B. Information in RNA uses thermal energy to make protein.
C. Information in RNA mutates into DNA and then is made into protein.
D. Information in DNA is transferred into RNA and then made into protein.
What is the complimentary mRNA sequence to the DNA sequence A-T-T-G-C-A?
A. T-A-A-C-G-T
C. U-A-A-C-G-U
B. U-A-A-C-G-T
D. T-A-A-G-C-U
Why is the presence of DNA important for the cellular metabolic activities?
A. DNA directs the production of enzymes.
B. DNA is a structural component of the cell membranes.
C. DNA directly increases the solubility of nutrients.
D. DNA is the major component of cytoplasm.
What did Francesco Redi’s experiments disprove?
A. law of superposition
B. Cambrian explosion of life
C. endosymbiont theory
D. theory of spontaneous generation
What provides an explanation for the presence of mitochondria and chloroplasts in presentday cells?
A. biogenesis
C. spontaneous generation
B. endosymbiosis
D. superposition
How is the illustration below interpreted by many scientists?
A. Mitochondria and chloroplasts are parasites in cells.
B. Prokaryotes might have entered host cells as prey or parasites.
C. Eukaryotic cells evolved before prokaryotes.
D. Mitochondria and chloroplasts look similar.
When Charles Darwin was developing his theory of evolution, he considered variations in a population
important. However, he could not explain how the variations occurred. Which two processes could cause
variations?
A. symbiosis and metamorphosis
B. commensalism and mutualism
C. crossing over and mutations
D. phagocytosis and pinocytosis
Why are the structures shown below considered to be homologous?
A. They belong to organisms that evolved from separate ancestors.
B. They are the result of geographic isolation.
C. They belong to organisms that probably evolved from a common
ancestor.
D. They are the result of sympatric speciation.
Homologous structures might be the result of a change in allele frequencies over successive generations. Why
have these structures probably continued?
A. They were beneficial in a particular environment.
B. They were predestined in a species.
C. They made a particular organism more attractive to a mate.
D. They were neutral, not harmful, mutations.
What unique characteristic would the beetles shown below develop through biological adaptation if, over a
period of years, the bark on the trees shown became spotted?
A. The beetles would become spotted.
B. The beetles would become plain.
C. About half the beetles would become spotted and half would not.
D. There would be no change.
According to the theory of natural selection, why are some individuals more likely than others to survive and
reproduce?
A. They pass on to their offspring new characteristics they acquired during their lifetimes.
B. They are better adapted to exist in their environment than others.
C. They do not pass on to their offspring new characteristics they have acquired during their lifetimes.
D. They tend to produce fewer offspring than do others in the same environment.
In order for evolution to occur, what must happen in a population?
A. genetic drift
C. natural selection
B. geographic isolation
D. reproductive isolation
What is operating when unrelated species living in different parts of the world, but with similar niches, evolve
similar traits?
A. convergent evolution
C. divergent evolution
B. genetic drift
D. parallelism
Scientists can estimate more accurately at what point various groups of organisms diverged evolutionarily from
one another by using which source of information?
A. fossil record
C. migration patterns
B. DNA evidence
D. genetic equilibrium
What type of natural selection favors average individuals in a population?
A. disruptive selections
C. directional selection
B. bias
D. stabilizing selection
Define gene.
A section of dna that codes for a trait
Put in order from biggest to smallest, DNA, Gene, Chromosome.
DNA – Chromosome-gene
Compute the number of chromosomes that the gametes of a cat (2n = 38 chromosomes) will have. Show your
work.
38/2 = 19
Describe the structure of DNA proposed by Watson and Crick.
The structure was a double helix that twists as it goes
Apply Chargaff ’s rule to decide how many guanine bases a length of DNA will have if it has 26 cytosine bases.
Explain.
It would 26 guanine bases since A=G
Recall what happens to the DNA double helix so that DNA polymerase can begin adding appropriate nucleotides.
Dna Helicase unwinds DNA, proteins bind to the DNA, DNA primers get added to the strand of DNA
Explain what Okazaki fragments are.
Okazaki fragments are sections of DNA that get created on the lagging strand
Differentiate between transcription and translation.
Transcription makes RNA and translation makes proteins
Describe what paleontologists can infer from fossils.
They can see what happened in the past, what life forms existed
Describe the endosymbiont theory.
The endosymbiont theory states that prokaryotic cells lived with and entered other cells and created
eukaryotic cells
Examine how photosynthetic prokaryotic cells changed the atmosphere of early Earth.
They added enough oxygen to create the atmosphere we have today that contain sustain larger organisms
Compare and contrast artificial and natural selection.
Artificial selection is when we select the traits we think are desirable and natural selection is when the
environment selects the traits
Define adaptation as it relates to evolution.
Adaptation is any characteristic that helps an organism survive
Match the phase of mitosis with the event (some will be used more than once some not at all).
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
A Nuclear membrane disappears
D Chromosomes start to unwind
A Chromatin condenses into chromosomes
C Chromosomes start to pull apart
B Chromosomes line up at the center
D Nuclear membrane reappears
In what stage of the cell cycle does the DNA Replicate?
Interphase
List 3 differences between mitosis and meiosis.
1. Number of Cells
– Mitosis creates 2 identical cells
– Meiosis creates 4 individual cells
2. Number of chromosomes
– Mitosis creates cells with 46 chromosomes (2n – diploid)
– Meiosis creates cells with 23 chromosomes (n – haploid)
3. Locations
– Mitosis – somatic (“normal”) cells
– Meiosis – gametes (sex) cells
Label the following as homozygous (HO) or heterozygous (HE).
AA HO Bb HE ff HO
For each of the genotypes below, write the phenotype.
Round seeds are dominant to wrinkled
RR ____Round_______________________
rr ______Wrinkled_____________________
Rr _______Round____________________
For each phenotype, write the genotype. (Remember to use the letter of the dominant trait).
Brown eyes are dominant to blue eyes.
______bb________ Blue
_____BB,Bb_________ Brown
Directions: For the next questions, use the Punnett square below.
B= Brown eyes and b=blue eyes
Parent 2
B
b
B
Parent 1
bb
What is the genotype of parent 1? ________Bb_________________
What is the phenotype of parent 2? __________Brown eyes______________
What is the phenotype of the offspring in box with an “X”? ___________Brown eyes____________
What is the genotype of the offspring in the box with an “X”? __________BB___________
What is the genotypic ratio of the offspring of the above cross? _________1:2:1_______________
Short hair is dominant over long hair in cats. Two heterozygous parents, Hh, are crossed.
a. What is the chance of getting a long hair cat? 25%
b. What is the genotypic ratio of the kittens? 1:2:1
c. What is the chance of getting a short hair cat? 75%
In people, the alleles for hair texture are an incomplete dominance. Your hair can be curly, straight or wavy.
Predict the children when a wavy haired mom (CS) and a straight-haired dad (SS) have children.
a. What is the predicted genotypic ratio for the children? 2:2
b. What is the predicted phenotypic ratio for the children? 2:2
In dogs, black hair color (B) is dominant over a yellow hair color (b). One parent is heterozygous for black hair,
while the other has yellow hair.
a. What is the probability of having yellow-haired puppies? 50%
In chickens, when a white rooster (FF) is crossed with a black hen (NN), all the chicks are black and white
speckled. What chicks will be made if the speckled chicks mate?
a. What are the genotypes you will get? White, speckled, and black
b. What is the chance of each genotype? 25% FF, 50% FN, and 25% NN
c. What is the chance of getting a white chicken? 25%
In pea plants, T=tall and t=short. Which phenotypic ratio results when a heterozygous plant and a recessive
plant are crossed? Tall:Short = 2:2
If a man with normal vision and his wife who is a carrier for colorblindness are crossed, looking at just their male
children, what percent will be colorblind?
25%
A color-blind son has a father and a mother, both with normal vision. What must be the mother’s genotype?
XRX r
In snapdragons, plant color is an incomplete dominant trait. The plants can be red (RR), white (WW) or pink
(RW). A red flower and a pink flower were crossed. Answer the following questions.
a. What is the chance of producing a white flower? 0%
b. What is the chance of producing a red flower? 50%
c. what is the genotypic ratio? 2:2
d. What is the percent chance of each genotype?50%
Vocabulary - Match the definitions with the terms.
D genotypes made of the same alleles
C different forms of genes for a single trait
B gene that is always expressed
E gene expressed only in homozygous state
A. alleles
B. dominant
C. heterozygous
D. homozygous
E. recessive
A genotypes made of two different alleles
A man with Type O blood marries a woman with heterozygous Type A blood.
What are the possible genotypes of the offspring? IAIi, ii
What are the possible phenotypes of the offspring? Heterozygous type a and type O
What is the probability of each genotype? 50%
What is the probability of each phenotype? 50%
In humans colorblindness (b) is an example of a sex-linked recessive trait. In this problem, a male with
colorblindness marries a female who is not colorblind but carries the (b) allele. What is the chance of having a
colorblind child?
50%
A man that has an AB blood type has a child with a woman with type B blood. Can they have a type O child?
No.
A man is heterozygous for type B blood. He has a child with a woman who is homozygous for type A blood.
What are the possible genotypes of their children? IAIB, IAi
What are the possible phenotypes of their children? AB and A
Match the words with the correct definition (some may be used more than once, some not at all)
A Unzips DNA
A. DNA helicase
B Adds nucleotides to DNA
B. DNA polymerase
C Fills in gaps in the DNA
C. DNA ligase
D Adds nucleotides to make RNA
D. RNA polymerase
Explain how the structure of DNA enables the molecule to be easily transcribed.
Dna can be unzipped and then put back together
Write out the sequence of the DNA segment that would replicate on this segment:
ACG TCG ATC GGT
TGC AGC TAG CCA
Transcribe the strand of DNA below.
AGG TTG ATC GCT
UCC AAC UAG CGA
Translate your transcribed DNA from the question above.
SERINE, ASPARAGINE, STOP CODON, ARGININE
Fill in the missing parts of the chart below.
Number of Strands
Nucleotides
DNA
2 STRANDS
Deoxyribose Sugar
RNA
1 Strand
Ribose sugar
A-T
C-G
A-U
C-G
Base Pairs
How many nucleotide bases make a codon? 3
How does the structure of DNA help explain the reason for the diversity of life that exists on earth?
Many combination of base pairs which make many different strands of RNA which produces different proteins
Fill in the missing information below
DNA
T A C
C G C
T A C
G T C
A T T
A C T
mRNA
AA
AUG
GCG
METH/START
AUG
ALANINE
CAG
UAA
METHIONINE
UGA
GLUTAMINE
STOP
STOP
Describe biogenesis?
Biogenesis says that life comes from life
What can fossils tell us?
Fossils tell us what happened in the past, what organisms existed
What was Lamarck’s theory of evolution?
Lamarck’s theory was that organisms acquire traits during their lifetime and then pass those traits on to their
offspring
What is fitness? Ability of an organism to survive, reproduce, and pass on their traits
Who came up with the idea of natural selection? Darwin
What is natural selection? Environment selects the traits, organisms best suited to their environment will survive
Where was the main place Charles Darwin traveled and studied? galapagos
In gazelles, there are 2 types: ones that run fast and those that run slowly. The fast gazelle can reach up to 40 miles an
hour. Lions love to eat gazelles, and they can reach speeds of up to 35-40 miles per hour. A gazelle will have
aproximately 2 babies a year, but many lions eat many of the young.
Identify the 5 points in the scenario above:
Population has variations. Fast and slow
Some variations are favorable. fast
More offspring are produced than survive 2 babies a year but most are eaten
Those that survive have favorable traits. Fast survive
A population will change over time. Population will become faster
List 4 pieces of evidence for evolution.
Homologous structures
Vesitgial structures
Embryological features
Amino acid sequences
Fossils
Draw and describe disruptive selection, directional selection, and stabilizing selection.
extreme phenotype has higher fitness than other phenotypes
intermediate phenotype has a higher fitness than extreme phenotypes
intermediate phenotypes are of lower fitness than extreme phenotypes
What happens in coevolution? Give an example.
Change of two or more species in close association with each other
Predators and prey
Parasites and hosts
Plant eating animals and plants
What happens in convergent evolution? Give an example.
Environment selects similar phenotypes although ancestral types were quite different
Sharks and dolphins
What happens in divergent evolution? Give an example.
Two or more related populations or species become more and more dissimilar
What is adaptive radiation? Give an example.
Many related species evolve from a single ancestral species. Galapagos finches
Complete the table by checking the correct column(s) with the description
Description
Homologous
Structure
Analogous Structure
Vestigial
Structure
Comparative
Biochemistry
Modified structure seen amond
different groups of descendents
Eyes in a blind fish
X
DNA and RNA comparisons that might
indicate evolutionary relationships
Bird wings and butterfly wings that
have the same function but different
structures
A body structure that is no longer used
for its original function but that might
have been used in an ancestor
X
X
X
X
Refer to the figure. Respond to each statement.
Specify which moth would survive if pollution increases.
B
State the name of the phenomenon illustrated
NATURAL SELECTION
Match the definition with the term (some may be used once, more than once, or not at all).
D Addition of a nucleotide
A. Nonsense mutation
D Deletion of a nucleotide
B. Point mutation
D Repeating sequence of codons
C. Missense Mutation
C Chemical change in 1 base pair
D. Frameshift
A 1 base pair is exchanged, code for wrong amino acid