Question 1

Which of the following best explains why individuals with heterochromia have irises of different colors?

Accepted Answer

Each iris contains a different amount of melanin due to variations in melanocyte distribution.

Question 2

A dihybrid cross is performed between Ttpp (tall, white flowers) and ttPp (short, purple flowers) plants. What is the expected phenotypic ratio in the offspring, assuming independent assortment?

Accepted Answer

$$1:1:1:1 ($$tall & purple : short & purple : tall & white : short & white)

Question 3

Which of the following statements about linked genes is correct?

Accepted Answer

Linked genes are located on the same chromosome and tend to be inherited together.

Question 4

In sickle cell anemia, what is the genotype of an individual who is a carrier but does not have the disease?

Accepted Answer

$$\beta^A\beta^S$$

Question 5

Why is the sickle cell trait considered evolutionarily beneficial in regions with high malaria prevalence?

Accepted Answer

It makes red blood cells less hospitable to malaria parasites, reducing infection severity.

Question 6

Hemophilia A is caused by a mutation in which gene, and what is its inheritance pattern?

Accepted Answer

F8 gene; X-linked recessive

Question 7

A biological male (XY) inherits an X-linked recessive allele for hemophilia from his mother. What is his phenotype?

Accepted Answer

He will be affected by hemophilia.

Question 8

Which of the following best describes incomplete dominance, as seen in snapdragon flowers?

Accepted Answer

Both alleles are partially expressed, resulting in an intermediate phenotype.

Question 9

If a person has blood type AB, which alleles do they possess, and what inheritance pattern does this demonstrate?

Accepted Answer

$$I^A I^B$$; co-dominance

Question 10

A Labrador retriever with genotype BbEe is crossed with a lab of genotype bbee. Which coat colors could their puppies have?

Accepted Answer

Black, chocolate, or yellow

Question 11

Which of the following is true about Y-linked traits?

Accepted Answer

They are only present in individuals with a Y chromosome and are passed from father to son.

Question 12

A parent with XY chromosomes has a Y-linked trait. If this parent has two sons and two daughters, which children will inherit the trait?

Accepted Answer

Only the sons

Question 13

Which of the following best explains why the law of independent assortment does not always apply to all genes?

Accepted Answer

Some genes are linked and located close together on the same chromosome.

Question 14

A woman who is a carrier for hemophilia (XHXh) and a man without hemophilia (XHY) have a child. What is the probability that their son will have hemophilia?

Accepted Answer

$$50\%$$

Question 15

Which of the following is an example of a polygenic trait?

Accepted Answer

Labrador retriever coat color

Question 16

Which of the following best describes the effect of the SRY gene?

Accepted Answer

It is the master switch for male-typical sexual development.

Question 17

If a gene is located on the X chromosome and is recessive, which of the following is true for a biological male (XY)?

Accepted Answer

He will express the trait if he inherits one copy of the allele.

Question 18

Which of the following is a real-world example of co-dominance?

Accepted Answer

ABO blood type, where both A and B antigens are expressed in AB individuals.

Question 19

Which of the following best describes the inheritance pattern of cystic fibrosis?

Accepted Answer

Autosomal recessive

Human Genetics: Mendelian and Non-Mendelian Inheritance, Chromosomal Theory, and Genetic Diseases

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