1. Biology Keystone Exam Review Packet

2. 26.) Use the table below to answer the question about codominance.
Blood Types
Blood type is inherited through multiple alleles, including IA, IB, and i. A child has type A blood. If the father has type AB blood, what are all the possible phenotypes of the mother?
A. Phenotypes O or A.
B. Phenotypes A or AB.
C. Phenotypes A, B, AB.
D. Phenotypes O, A, B, AB.
GENOTYPE(S):
PHENOTYPE(S): ii O
IAIA, IAi A
IBIB, IBi B
IAIB AB

3. IA IB IA IB IA IB IA IB IB IA i IB IA IB IA IB IA i i i IAIA IAIB IAIB
ANSWER: D
IAi
IBi IA i i i

4. 27.) A cattle farmer genetically crosses a cow (female) with a white coat with a bull (male) with a red coat. The resulting calf (offspring) is roan, which means there are red and white hairs intermixed in the coat of the calf. The genes for coat color in cattle are codominant.

5. Part A: Although a farm has cattle in all three colors, the farmer prefers roan cattle over white or red cattle. Use the Punnett square to show a cross that would produce only roan offspring.
R R RW W W

6. Part B: Explain how a roan calf results from one white-and one red-coated parent. In your explanation, use letters to represent genes. Be sure to indicate what colors the letters represent.
ANSWER:
A roan calf is a result of a homozygous RR (red) crossed with a homozygous WW (white). The roan color is co-dominant, resulting heterozygous RW (roan) genotype.

7. By crossing a two roan cattle, the result would be:
Part C: Predict the possible genotypes and phenotypes of the offspring produced from two roan cattle.
R W RR RW WW R W
By crossing a two roan cattle, the result would be:
RR = RW = WW = 1
Genotype: 1 : 2 : 1
Phenotype: 1 red, 2 roan, 1 white

8. 28.) Use the diagram below to answer the question.
Which type of change in chromosome composition is illustrated in the diagram?
A. deletion
B. insertion
C. inversion
D. translocation

9. ANSWER: D
The a chromosomal segment is moved from one position to another, either within the same chromosome or to another chromosome.
A - deletion: Not deleted.
B - insertion: Not inserted.
C - inversion: Not “flipped.”

10. 29.) Which statement describes a cell process that is common to both eukaryotic and prokaryotic cells?
A.) Both cell types carry out transcription in the nucleus.
B.) Both cell types use ribosomes to carry out translation.
C.) Both cell types assemble amino acids to carry out transcription.
D.) Both cell types carry our translation in the endoplasmic reticulum.

11. ANSWER: B
Both cell types use ribosomes to carry out translation.

12. A.) It stores all proteins for later use.
30.) The endoplasmic reticulum is a network of membranes within the cell, and it is often classified as rough or smooth, depending on whether there are ribosomes on its surface. Which statement best describes the role of rough endoplasmic reticulum in the cell?
A.) It stores all proteins for later use.
B.) It provides an attachment site for larger organelles.
C.) It aids in the production of membrane and secretory proteins.
D.) It stores amino acids required for the production of all proteins.

13. ANSWER: C
It aids in the production of membrane and secretory proteins.
A - A cell does not “store” proteins for later use.
B - It is not an attachment site.
D - It does not “store” amino acids either.

14. 31.) A genetic mutation resulted in a change in the sequence of amino acids of a protein, but the function of the protein was not changed. Which statement best describes the genetic mutation?
A.) It was a silent mutation that caused a change in the DNA of the organism.
B.) It was a silent mutation that caused a change in the phenotype of the organism
C.) It was a nonsense mutation that caused a change in the DNA of the organism.
D.) It was a nonsense mutation that caused a change in the phenotype of the organism.

15. A nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon, or a nonsense codon in the transcribed mRNA, and in a truncated, incomplete, and usually nonfunctional protein product.
DNA: 5' - ATG ACT CAC TGA GCG CGA AGC TGA - 3'
3' - TAC TGA GTG ACT CGC GCT TCG ACT - 5'
mRNA: 5' - AUG ACU CAC UGA GCG CGU AGC UGA - 3‘
Protein: Met Thr His Stop
Silent mutations are DNA mutations that either do not result in a change to the amino acid sequence of a protein or result in the insertion of an alternative amino acid with similar properties to that of the original amino acid.
ANSWER: A

16. 32.) Genetic engineering has led to genetically modified plants that resist insect and bacterial and fungal infections. Which outcome would most likely be a reason why some scientists recommend caution in planting genetically modified plants?
A. unplanned ecosystem interactions
B. reduced pesticide and herbicide use
C. improved agricultural yield and profit
D. increased genetic variation and diversity
ANSWER: A

17. 33.) Use the circle graphs below to answer the question.
The graphs illustrate change in a lizard population over time. Which process most likely led to the change in the lizard population?
A. natural selection for a trait that is beneficial to lizards
B. natural selection against a trait that is beneficial to lizards
C. artificial selection for a trait that is beneficial to lizards
D. artificial selection against a trait that is beneficial to lizards

18. ANSWER: A
Artificial selection (Selective breeding) is the process by which humans breed other animals and plants for particular traits.
Natural selection is the gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution.
If nature is working against the trait, the population of the lizards would decrease. We would not use artificial selection.

19. C. geographic isolation D. reproductive isolation
34.) In North America, the eastern spotted skunk mates in late winter, and the western spotted skunk mates in late summer. Even though their geographic ranges overlap, the species do not mate with each other. What most likely prevents these two species from:
A. habitat isolation
B. gametic isolation
C. geographic isolation
D. reproductive isolation
ANSWER: D
Because they have different mating seasons, breeding is not possible.
A - Not a habitat issue.
B - Eliminate this one.
C - Not a geographical issue.

20. B - This has nothing to do with predator species.
35.) A mutation occurs in the genes that code for coat color in deer. Which change will most likely result from this mutation?
A.) A change in the selection pressures acting on coat color.
B.) A change in the coat-color genes of deer predator species.
C.) An increase in coat-color diversity in the population.
D.) an increase in the number of genes for coat color in the population.
ANSWER: C
A - Eliminate this one.
B - This has nothing to do with predator species.
D - The number of genes will not change.

21. 36.) Use the illustration below to answer the question.
The skeletons of mammalian forelimbs represent variations of a structure that was present in their common ancestor. What has most likely caused the variation in forelimbs?
A. changes in muscle structure
B. changes in the genetic codes
C. trait formation due to behaviors
D. development of vestigial structures

22. ANSWER: B
• As we discovered in the whale study, slight changes in the genetic codes cause the progression of structures.
A - Not a cause for variation.
C - Not a cause for variation.
D - These are not examples vestigial structures.