What is the genetic material in the
chromosomes of an animal’s cells?
A. DNA
B. glucosamine
C. RNA
D. transcriptase
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An enzyme moves along a strand of DNA and produces a new nucleic acid strand. Part of the new strand is shown below.
GUACUCGGCAAUUUCGCA
Which of the following cellular processes created the new strand?
A. active transport
B. crossing over
C. replication
D. transcription
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A mutation occurs in an individual, but the individual’s phenotype does not change. Which of the following statements describes what most likely occurred to produce this result?
A. The mutation deleted a portion of a coding section of the DNA.
B. The mutation caused a portion of a coding section of the DNA to repeat.
C. The mutation affected a nucleotide in the DNA, but the mutation did not affect the sequence of amino acids synthesized.
D. The mutation translocated a group of nucleotides in the DNA, but the mutation did not change the number of base pairs in the DNA.
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In rabbits, a single gene with two alleles codes for ear shape. Two rabbits, each with a homozygous genotype, are mated. The female rabbit has straight ears and
the male rabbit has floppy ears. All the offspring have straight ears. Which of the following conclusions about rabbit genetics is best supported by the results of the cross
A. Offspring rabbits receive alleles only from their mothers.
B. The allele for straight ears is dominant to the allele for floppy ears.
C. Alleles in female rabbits are always more dominant than alleles in male rabbits.
D. The allele for straight ears and the allele for floppy ears are on different chromosomes.
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Reading: People may be Rh-positive or Rh-negative for their blood types. Rh-positive individuals have Rh factors, or markers, on the surface of their red blood cells. Rh-negative individuals do not have these markers. Several genes code for Rh factors.
The D allele, which codes for one type of Rh marker, is responsible for the majority of Rh-positive phenotypes. Because of this, the D and d alleles are often used to describe Rh blood type inheritance.
Determining Rh blood type inheritance is especially important when an Rh-negative woman is pregnant. If the baby is Rh-positive, the woman is treated with a special medicine so she does not produce antibodies that attack the baby’s red blood cells.
Questions:
a. Using the given allele symbols, identify the genotype of an Rh-negative woman.
b. Draw Punnett squares to represent all the different crosses in which an Rh-negative woman could have an Rh-positive baby.
c. For each Punnett square you drew in part (b), determine the percent chance that the baby will be Rh-positive.
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Feb 2016 MCAS.
The stored information in DNA codes for which of the following?
A. proteins
B. simple sugars
C. mitochondria when energy is needed
D. large vacuoles when nutrients are abundant
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Feb 2016 MCAS.
A type of golden brown coat color in horses is called palomino. Several pairs of palomino horses are mated. The results of the crosses are here:
Coat Color – Percent of Offspring
palomino 50% reddish-brown 25% creamy white 25%
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Feb 2016 MCAS. Which of the following is the most likely inheritance pattern of coat color in horses?
A. complete dominance
B. incomplete dominance
C. polygenic inheritance
D. sex-linked inheritance
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Which of the following statements explains the importance of enzymes that check for and repair mistakes during DNA replication?
A. The enzymes replace the DNA with RNA.
B. The enzymes speed up the rate of RNA synthesis.
C. The enzymes remove many recessive gene copies from the nucleus.
D. The enzymes prevent many genetic mutations from being expressed.
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Feb 2016 MCAS. (42) Four boys have the same biological mother and father. What percentage of each boy’s chromosomes come from the mother?
A. 0% . B. 25% . C. 50% . D. 100%
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Feb 2017 MCAS. A red-eyed male fruit fly is crossed with a heterozygous red-eyed female fruit fly. The expected results for the cross are shown in the table below.

Which of the following describes this inheritance pattern and the allele that codes for red eye color in fruit flies?
A. The inheritance pattern is sex-linked, and the allele for red eye color is dominant.
B. The inheritance pattern is sex-linked, and the allele for red eye color is recessive.
C. The inheritance pattern is codominant, and the allele for red eye color masks the allele for white eye color.
D. The inheritance pattern is codominant, and the alleles for red eye color and
white eye color are expressed equally
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The diagram below represents a biological process involving DNA.

What process is represented?
A. fertilization . B. mutation . C. replication . D. translation
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Feb 2017. The bacterium E. coli is a model organism used by many scientists for genetic and biochemical research. Which of the following statements helps explain why E. coli is so frequently used for research?
A. It has a large nucleus and a long generation time.
B. It has hundreds of chromosomes and a long lifespan.
C. It has a simple cell structure and reproduces rapidly.
D. It has many kinds of organelles and reproduces sexually.
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Spring 2017 MCAS
In tigers, the allele for orange fur is dominant to the allele for white fur. If two heterozygous tigers mate and produce offspring, what is the probability of an individual offspring having white fur?
A. 0 . B. 1/4 . C. 1/2 . D. 1.0
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Spring 2017 MCAS
The diagram below represents structures and processes involved in protein synthesis in an animal cell. Four parts of the diagram are labeled W, X, Y, and Z.

Which part of the diagram represents transcription?
A. part W B. part X C. part Y D. part Z
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Spring 2017
A particular species of moth can have green or yellow scales on its wings. The scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. When moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales. Based on this information, how do the alleles for scale color interact?
A. The green allele is dominant to the yellow allele.
B. The green allele is recessive to the yellow allele.
C. The green allele and the yellow allele are codominant.
D. The green allele and the yellow allele are incompletely dominant.
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Spring 2017
Lipids, carbohydrates, and DNA all exist in human cells as long molecular chains. Which of the following describes how DNA differs from lipids and carbohydrates?
A. Only DNA has carbon atoms.
B. Only DNA is found in the cytoplasm.
C. Only DNA is needed to create new cells.
D. Only DNA contains genetic information.
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Spring 2017
For a new liver cell to form, DNA replication is necessary because it ensures that the newly formed cell has which of the following?
A. two copies of the original cell’s DNA
B. an identical copy of the original cell’s DNA
C. a rearranged copy of the original cell’s DNA
D. only the best parts of the original cell’s DNA
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Spring 2017
A scientist is studying the inheritance of two genes, gene R and gene P, in dogs. Each gene is located on a different chromosome. Gene R has two alleles, R and r, and gene P has two alleles, P and p.
What are the expected probabilities for the genotypes of gametes produced by a dog with the genotype RrPp?
A. 50% Rr and 50% Pp
B. 50% RP and 50% rp
C. 50% Rp, 25% rP, and 25% rp
D. 25% RP, 25% Rp, 25% rP, and 25% rp
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Spring 2017
The diagram below shows a parent cell and the daughter cells that are produced
after the parent cell divides.

Which of the following best describes the daughter cells?
A. They are a result of transcription.
B. They are a result of binary fission.
C. They have half the number of lipids that the parent cell has.
D. They have half the number of chromosomes that the parent cell has.
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Spring 2017
In humans, an X-linked recessive allele (Xb) causes red-green colorblindness. Which of the following crosses could produce a female who is red-green colorblind?

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Spring 2017
Which of the following describes a mutation in a parent that could change the phenotype of its future offspring?
A. a mutation in the RNA of a skin cell
B. a mutation in the DNA of a liver cell
C. a mutation in the RNA of a brain cell
D. a mutation in the DNA of a sperm cell
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Spring 2017
The chromosomes of a human female are shown below. The chromosomes are
arranged in pairs. The 23rd pair, labeled XX, is the sex chromosomes.

Which of the following would the female normally pass on to her child?
A. all 46 of the chromosomes
B. 23 chromosomes, one from each pair
C. a random set of any 23 of the chromosomes
D. the first 11 chromosome pairs, plus one sex chromosome
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Spring 2017: These are open-response questions.
Instructions: Show all your work (diagrams, tables, or computations) in your Student Answer Booklet. If you do the work in your head, explain in writing how you did the work. Write your answer in the space provided in your Student Answer Booklet.
A certain genetic disorder is caused by a single base mutation in the DNA of a certain gene. The mutation changes the amino acid glutamate (Glu) to aspartate (Asp).
a. Identify the type of macromolecule (carbohydrate, lipid, nucleic acid, protein) that changes when Glu changes to Asp. Explain your answer.
A portion of the amino acid sequence that includes this mutation is shown below.
Val-Ser-Ala-Arg-Asp
The sample of DNA below is being analyzed to determine if a patient has the genetic disorder.
3’ CAA-TCG-CGG-TCT-CTT 5’
b. Determine the mRNA sequence from the patient’s DNA sequence.
c. Using the information in the codon table below, determine the amino acid sequence that is coded for by the mRNA sequence you determined in part (b).
d. Determine whether the patient has the genetic disorder. Explain your answer.

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A newly discovered gene has two alleles, A and a.
Scientists hypothesize that the alleles show incomplete dominance.
Which of the following statements provides evidence for incomplete dominance?
A. Analysis of the DNA shows that only males have genotype AA.
B. Individuals with genotype aa survive only a few days after birth.
C. Individuals with genotype AA and individuals with genotype Aa both have the same phenotype.
D. Crosses between two individuals with genotype Aa result in three different phenotypes among the offspring.
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A single gene with two alleles codes for the fruit color (red and yellow) of tomato plants. Two tomato plants heterozygous for fruit color are crossed. The table below shows the results of the cross. Based on the results, what is the most likely inheritance pattern of the alleles for fruit color?

A. The alleles for red color and for yellow color are polygenic.
B. The alleles for red color and for yellow color are codominant.
C. The allele for red color is recessive to the allele for yellow color.
D. The allele for red color is dominant to the allele for yellow color.
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In Labrador retrievers, the black fur allele (B) is dominant to the brown fur allele (b).
A black male dog and a brown female dog are mated and have a litter of eight puppies. Five puppies are black and three puppies are brown. What are the genotypes of the parent dogs?
A. BB and Bb
B. Bb and Bb
C. Bb and bb
D. BB and bb
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Based on the results of genetic crosses, Mendel concluded that the alleles for seed color and seed shape in pea plants assorted independently. Which of the following statements best explains why the alleles for each trait assorted independently in Mendel’s experiments?
A. The alleles were all recessive.
B. The alleles were all dominant.
C. The alleles were on separate chromosomes.
D. The alleles were inherited in a sex-linked manner.
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Scientists compared the DNA sequence of a gene in four mammals. A portion of the gene’s DNA sequence in each mammal is shown below.

Based on the sequence data, which of the mammals are most closely related to each other?
A. mammals 1 and 2
B. mammals 1 and 3
C. mammals 2 and 4
D. mammals 3 and 4
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2014 MCAS Open response question
The inheritance patterns for some traits in guinea pigs are listed in the table below.

a. Identify the phenotype of a guinea pig with the genotype HhBBrr.
b. Using allele symbols in the table above, identify the genotype of a guinea pig that is
recessive for hair length, heterozygous for hair color, and homozygous dominant for hair texture.
Suppose the guinea pigs from parts (a) and (b) are crossed.
c. Identify the percent of offspring that will have black hair. To support your answer, draw a Punnett square for the hair color trait.
d. Considering only hair length, identify the expected phenotype ratio of the offspring.
Draw a Punnett square to support your answer.
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