Question 1

A couple has six daughters and is expecting a seventh child. What is the probability that this child will be a boy?

Accepted Answer

A)  1/2 
B)  1/4 
C)  1/16 
D)  1/64 
E)  1/128 
A)  1/2 
B)  1/4 
C)  1/16 
D)  1/64 
E)  1/128 A

Question 2

The figure shows that independent assortment results from the segregation of chromosomes at anaphase I of meiosis. Assuming four functional products of meiosis and no crossing over, what is the minimum number of meiotic events (an event consisting of the two meiotic divisions) to produce the RY, Ry, rY, and ry gametes?

Accepted Answer

A)  one 
B)  two 
C)  three 
D)  four 
E)  A correct answer can't be determined. 
A)  one 
B)  two 
C)  three 
D)  four 
E)  A correct answer can't be determined. B

Question 3

A man has either an AaBB or AABb genotype with equal probability. Assume these genes assort independently. What is the overall probability that the man will produce an Ab gamete?

Accepted Answer

To determine the overall probability that the man will produce an Ab gamete, we need to consider both possible genotypes (AaBB and AABb) and calculate the probability of an Ab gamete for each, then average them since he has an equal probability of having either genotype.

For the AaBB genotype:
- The probability of contributing an A allele from the Aa pair is 1/2 (since he can contribute either A or a).
- The probability of contributing a B allele from the BB pair is 1 (since both alleles are B, he can only contribute a B).

So, the probability of an Ab gamete from the AaBB genotype is 0, because he cannot produce an Ab gamete with this genotype (he can only produce AB or aB gametes).

For the AABb genotype:
- The probability of contributing an A allele from the AA pair is 1 (since both alleles are A, he can only contribute an A).
- The probability of contributing a b allele from the Bb pair is 1/2 (since he can contribute either B or b).

So, the probability of an Ab gamete from the AABb genotype is 1 * 1/2 = 1/2.

Now, we average the probabilities from both genotypes:

(Probability from AaBB + Probability from AABb) / 2
= (0 + 1/2) / 2
= 1/2 / 2
= 1/4

Therefore, the overall probability that the man will produce an Ab gamete is 1/4 or 25%.

Question 4

In Labrador retrievers, black coat color is dominant to brown. Suppose that a black Lab is mated with a brown one and the offspring are four black puppies and one brown puppy. What can you conclude about the genotype of the black parent?

Accepted Answer

A)  The genotype must be BB. 
B)  The genotype must be bb. 
C)  The genotype must be Bb. 
D)  The genotype could be either BB or Bb. 
E)  The genotype cannot be determined from these data. 
A)  The genotype must be BB. 
B)  The genotype must be bb. 
C)  The genotype must be Bb. 
D)  The genotype could be either BB or Bb. 
E)  The genotype cannot be determined from these data.

Question 5

Which of the following statements is TRUE?

Accepted Answer

A)  The genotype is the physical appearance of a trait. 
B)  Alleles, genes, and loci are different names for the same thing. 
C)  The phenotype of a dominant allele is never seen in the F1 progeny of a monohybrid cross. 
D)  A testcross can be used to determine whether an individual is homozygous or heterozygous for a dominant allele. 
A)  The genotype is the physical appearance of a trait. 
B)  Alleles, genes, and loci are different names for the same thing. 
C)  The phenotype of a dominant allele is never seen in the F1 progeny of a monohybrid cross. 
D)  A testcross can be used to determine whether an individual is homozygous or heterozygous for a dominant allele.

Question 6

Gregor Mendel carried out a cross between two pea plants by taking pollen from a plant that was homozygous for round seeds and dusting the pollen onto the stigma of a plant homozygous for wrinkled seeds. Which of the following would be the reciprocal cross that Mendel had carried out for this experiment?

Accepted Answer

A)  Stigma of a plant homozygous for round seed pollinated with pollen from a plant homozygous for wrinkled-seed plant 
B)  Stigma of a plant homozygous for round seed pollinated with pollen from a plant heterozygous for wrinkled-seed plant 
C)  Stigma of a plant heterozygous for round seed pollinated with pollen from a plant homozygous for wrinkled-seed plant 
D)  Stigma of a plant homozygous for wrinkled seed pollinated with pollen from a plant homozygous for round-seed plant 
E)  Stigma of a plant homozygous for wrinkled seed pollinated with pollen from a plant homozygous for wrinkled-seed plant 
A)  Stigma of a plant homozygous for round seed pollinated with pollen from a plant homozygous for wrinkled-seed plant 
B)  Stigma of a plant homozygous for round seed pollinated with pollen from a plant heterozygous for wrinkled-seed plant 
C)  Stigma of a plant heterozygous for round seed pollinated with pollen from a plant homozygous for wrinkled-seed plant 
D)  Stigma of a plant homozygous for wrinkled seed pollinated with pollen from a plant homozygous for round-seed plant 
E)  Stigma of a plant homozygous for wrinkled seed pollinated with pollen from a plant homozygous for wrinkled-seed plant

Question 7

In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.)

Accepted Answer

A)  3/256 
B)  3/32 
C)  3/16 
D)  3/8 
E)  3/4 
A)  3/256 
B)  3/32 
C)  3/16 
D)  3/8 
E)  3/4

Question 8

Albinism is a recessive condition resulting from the inability to produce the dark pigment melanin in skin and hair. A man and woman with normal skin pigmentation want to have two children. The man has one parent with albinism; the woman has parents with normal pigmentation but a brother with albinism.
a. What is the probability that at least one child will be have albinism?
b. What is the probability of both children having normal pigmentation?

Accepted Answer

To solve this problem, we need to unders

Question 9

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. 
-What is the probability of producing an offspring with the AB phenotype from a cross of aabb × AABB?

Accepted Answer

A)  1/4 
B)  1/2 
C)  1/16 
D)  9/16 
E)  1 (100%) 
A)  1/4 
B)  1/2 
C)  1/16 
D)  9/16 
E)  1 (100%)

Question 10

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. 
-What is the probability of producing an AABB zygote from a cross of AaBb × AaBb?

Accepted Answer

A)  1/4 
B)  1/2 
C)  1/16 
D)  9/16 
E)  1 (100%) 
A)  1/4 
B)  1/2 
C)  1/16 
D)  9/16 
E)  1 (100%)

Question 11

Honeybees have a haplo-diploid sex determination system where females develop from a fertilized egg (they are diploid, having one allele from the female queen and one allele from the male), and males develop from unfertilized eggs (they are haploid, having only one allele from the queen). Assuming that the female parent (queen) is heterozygous for a particular gene, what is the probability that a female offspring will inherit the recessive allele from her mother? What is the probability that a male offspring will inherit a recessive allele from his mother?

Accepted Answer

A)  The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 50%. 
B)  The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 100%. 
C)  The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 50%. 
D)  The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 100%. 
E)  The probability that a daughter will inherit a recessive allele from her mother is 0%; the probability that a son will inherit a recessive allele from his mother is 100%. 
A)  The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 50%. 
B)  The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 100%. 
C)  The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 50%. 
D)  The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 100%. 
E)  The probability that a daughter will inherit a recessive allele from her mother is 0%; the probability that a son will inherit a recessive allele from his mother is 100%.

Question 12

If an organism of genotype Aa was used for a testcross, what was the genotype of the other individual used in the cross?

Accepted Answer

A)  AA 
B)  Aa 
C)  aa 
D)  Either Aa or aa 
E)  Either AA or Aa 
A)  AA 
B)  Aa 
C)  aa 
D)  Either Aa or aa 
E)  Either AA or Aa

Question 13

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.
- The F1 progeny are allowed to self-fertilize. What is the probability of obtaining a wrinkled, green seed in the F2?

Accepted Answer

A)  3/4 
B)  1/16 
C)  9/16 
D)  3/16 
E)  1/2 
A)  3/4 
B)  1/16 
C)  9/16 
D)  3/16 
E)  1/2

Question 14

Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation?

Accepted Answer

A)  AA × AA 
B)  AA × aa 
C)  Aa × Aa 
D)  Aa × aa 
E)  aa × aa 
A)  AA × AA 
B)  AA × aa 
C)  Aa × Aa 
D)  Aa × aa 
E)  aa × aa

Question 15

A man has either an AaBB or AABb genotype with equal probability. Assume these genes assort independently. What is the probability of the man producing an AB gamete?

Accepted Answer

To determine the probability of the man

Question 16

The ability to curl one's tongue into a U-shape is a genetic trait. Curlers always have at least one curler parent but noncurlers can have one or both parents who are curlers. Using C and c to symbolize the alleles that control this trait, what is the genotype of a noncurler?

Accepted Answer

A)  CC 
B)  Cc 
C)  cc 
D)  CC or Cc 
A)  CC 
B)  Cc 
C)  cc 
D)  CC or Cc

Question 17

In Mendel's peas, purple flower color is dominant to white. From which of the following descriptions can you NOT infer the genotype completely?

Accepted Answer

A)  purple 
B)  white 
C)  pure-breeding purple 
D)  pure-breeding white 
E)  heterozygous 
A)  purple 
B)  white 
C)  pure-breeding purple 
D)  pure-breeding white 
E)  heterozygous

Question 18

In a cross between AaBbCc and AaBbcc, what proportion of the offspring would be expected to be A_bbcc? (A_ means AA or Aa.)

Accepted Answer

A)  3/256 
B)  3/32 
C)  3/16 
D)  3/8 
E)  3/4 
A)  3/256 
B)  3/32 
C)  3/16 
D)  3/8 
E)  3/4

Question 19

Which of the following was NOT one of Mendel's conclusions based on his monohybrid crosses?

Accepted Answer

A)  Genes are carried on chromosomes. 
B)  Alleles exist in pairs. 
C)  Alleles segregate equally into gametes. 
D)  Alleles behave as particles during inheritance. 
E)  One allele can mask the expression of the other allele. 
A)  Genes are carried on chromosomes. 
B)  Alleles exist in pairs. 
C)  Alleles segregate equally into gametes. 
D)  Alleles behave as particles during inheritance. 
E)  One allele can mask the expression of the other allele.

Question 20

A phenotypically normal man has phenotypically normal parents but he has a sister who has cystic fibrosis caused by a recessive mutant allele. What is the probability that the man is heterozygous for the cystic fibrosis allele?

Accepted Answer

A)  1/4 
B)  1/2 
C)  3/4 
D)  2/3 
E)  1/3 
A)  1/4 
B)  1/2 
C)  3/4 
D)  2/3 
E)  1/3

Exam 3: Basic Principles of Heredity

A couple has six daughters and is expecting a seventh child. What is the probability that this child will be a boy?

A man has either an AaBB or AABb genotype with equal probability. Assume these genes assort independently. What is the overall probability that the man will produce an Ab gamete?

In Labrador retrievers, black coat color is dominant to brown. Suppose that a black Lab is mated with a brown one and the offspring are four black puppies and one brown puppy. What can you conclude about the genotype of the black parent?

Which of the following statements is TRUE?

In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. -What is the probability of producing an offspring with the AB phenotype from a cross of aabb × AABB?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. -What is the probability of producing an AABB zygote from a cross of AaBb × AaBb?

If an organism of genotype Aa was used for a testcross, what was the genotype of the other individual used in the cross?

Which of the following crosses would produce a 1:1 ratio of phenotypes in the next generation?

A man has either an AaBB or AABb genotype with equal probability. Assume these genes assort independently. What is the probability of the man producing an AB gamete?

The ability to curl one's tongue into a U-shape is a genetic trait. Curlers always have at least one curler parent but noncurlers can have one or both parents who are curlers. Using C and c to symbolize the alleles that control this trait, what is the genotype of a noncurler?

In Mendel's peas, purple flower color is dominant to white. From which of the following descriptions can you NOT infer the genotype completely?

In a cross between AaBbCc and AaBbcc, what proportion of the offspring would be expected to be A_bbcc? (A_ means AA or Aa.)

Which of the following was NOT one of Mendel's conclusions based on his monohybrid crosses?

A phenotypically normal man has phenotypically normal parents but he has a sister who has cystic fibrosis caused by a recessive mutant allele. What is the probability that the man is heterozygous for the cystic fibrosis allele?

Introduction to Genetics

Chromosomes and Cellular Reproduction

Sex Determination and Sex-Linked Characteristics

Extensions and Modifications of Basic Principles

Pedigree Analysis, Applications, and Genetic Testing

Linkage, Recombination, and Eukaryotic Gene Mapping

Chromosome Variation

Bacterial and Viral Genetic Systems

DNA: the Chemical Nature of the Gene

Chromosome Structure and Organelle Dna

DNA Replication and Recombination

Transcription

Rna Molecules and Rna Processing

The Genetic Code and Translation

Control of Gene Expression in Prokaryotes

Control of Gene Expression in Eukaryotes

Gene Mutations and Dna Repair

Molecular Genetic Analysis and Biotechnology

Genomics and Proteomics

Epigenetics

Developmental Genetics and Immunogenetics

Cancer Genetics

Quantitative Genetics

Population Genetics

Evolutionary Genetics

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