Question 1

Which of the following best describes the Law of Segregation as demonstrated by Mendel's monohybrid cross with pea plants?

Accepted Answer

Each individual has two alleles for each gene, and these alleles separate during gamete formation so that each gamete receives only one allele.

Question 2

A woman with blood type AB has a child with a man who is blood type O. Which of the following blood types could their child have?

Accepted Answer

Type A or Type B

Question 3

In a dihybrid cross between two heterozygous tomato plants (PpCc x PpCc), where P = purple stem (dominant), p = green stem (recessive), C = cut leaf (dominant), and c = potato leaf (recessive), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

9 purple, cut : 3 purple, potato : 3 green, cut : 1 green, potato

Question 4

Which of the following best explains why males are more likely than females to express sex-linked recessive diseases?

Accepted Answer

Males have only one X chromosome, so a single recessive allele on the X chromosome will result in the disease.

Question 5

A cross between a true-breeding tall pea plant (TT) and a true-breeding dwarf pea plant (tt) produces F1 offspring. If two F1 plants are crossed, what is the expected genotypic ratio in the F2 generation?

Accepted Answer

$$1\ TT : 2\ Tt : 1\ tt$$

Question 6

In chickens, the frizzle trait shows incomplete dominance. If a heterozygous frizzled bird (Ff) is crossed with another heterozygous frizzled bird (Ff), what is the expected phenotypic ratio in the offspring?

Accepted Answer

1 normal : 2 mild frizzle : 1 highly frizzled

Question 7

A male parakeet homozygous dominant for green feathers and large beak (GG BB) is crossed with a female homozygous recessive for both traits (gg bb). What will be the genotype and phenotype of the F1 offspring?

Accepted Answer

All F1 will be Gg Bb and display green feathers with large beaks.

Question 8

Which of the following best describes polygenic inheritance?

Accepted Answer

A single trait is controlled by multiple genes, resulting in a range of phenotypes.

Question 9

If a female is a carrier for a sex-linked recessive disease (X$$^NX$^n) $$and the male is normal (X$$^NY$$), what is the probability that their son will have the disease?

Accepted Answer

$$50\%$$

Question 10

Which of the following is true regarding nondisjunction during meiosis?

Accepted Answer

It can result in gametes with an abnormal number of chromosomes, leading to aneuploidy.

Question 11

A woman who is a carrier for hemophilia (a sex-linked recessive disorder) marries a man with hemophilia. What is the probability that their daughter will have hemophilia?

Accepted Answer

$$50\%$$

Question 12

Which of the following best describes codominance?

Accepted Answer

Both alleles are fully expressed in the phenotype of a heterozygote.

Question 13

If a true-breeding purple-stemmed, cut-leaf tomato (PPCC) is crossed with a true-breeding green-stemmed, potato-leaf tomato (ppcc), what will be the genotype and phenotype of the F1 generation?

Accepted Answer

All F1 will be PpCc and display purple stems with cut leaves.

Question 14

Which of the following is the universal donor blood type, and why?

Accepted Answer

Type O negative, because it lacks A, B, and Rh antigens.

Question 15

A child is born with Down syndrome, which is caused by trisomy 21. Which meiotic error most likely led to this condition?

Accepted Answer

Nondisjunction during meiosis, resulting in an extra chromosome 21.

Question 16

Which of the following statements about autosomes and sex chromosomes in humans is correct?

Accepted Answer

Humans have 22 pairs of autosomes and 1 pair of sex chromosomes.

Question 17

If a heterozygous tall pea plant (Tt) is crossed with a dwarf pea plant (tt), what is the expected phenotypic ratio of the offspring?

Accepted Answer

1 tall : 1 dwarf

Question 18

Which of the following best describes a genotype?

Accepted Answer

The genetic makeup of an organism for a particular trait.

Question 19

A woman with type A blood (genotype I$$^AI$^O) $$and a man with type B blood (genotype I$$^BI$^O) $$have a child. Which blood types are possible for their child?

Accepted Answer

Type A, Type B, Type AB, or Type O

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