Q: In a dihybrid cross between a GgSs plant and a ggSs plant (where G = green, g = yellow, S = striped, s = solid), what is the expected phenotype ratio among the offspring?

$$3\ \text{Green Striped} : 1\ \text{Green Solid} : 3\ \text{Yellow Striped} : 1\ \text{Yellow Solid}$$

Question 1

Gregor Mendel is often referred to as the 'father of genetics.' Which of the following best describes his most significant contribution to biology?

Accepted Answer

He established the principles of inheritance through experiments with pea plants.

Question 2

A true-breeding plant with purple flowers is crossed with a true-breeding plant with white flowers. All offspring in the F1 generation have purple flowers. What does this indicate about the purple flower allele?

Accepted Answer

It is a dominant allele.

Question 3

In a dihybrid cross between a GgSs plant and a ggSs plant (where G = green, g = yellow, S = striped, s = solid), what is the expected phenotype ratio among the offspring?

Accepted Answer

$$3\ 	ext{Green Striped} : 1\ 	ext{Green Solid} : 3\ 	ext{Yellow Striped} : 1\ 	ext{Yellow Solid}$$

Question 4

A person with genotype $$I^A I^B$$ for the ABO blood group will have which of the following phenotypes?

Accepted Answer

Type AB blood with both A and B antigens on red blood cells

Question 5

If a woman with type AB blood ($$I^A I^B) $$and a man with type O blood ($$ii) $$have a child, what are the possible blood types for their child?

Accepted Answer

Type A or Type B

Question 6

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote displays a phenotype intermediate between the two homozygotes.

Question 7

A test cross is performed to determine the genotype of a plant with a dominant phenotype. Which of the following best describes the process?

Accepted Answer

Crossing the plant with a homozygous recessive plant

Question 8

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

Accepted Answer

Height

Question 9

A pedigree chart shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 10

Which of the following statements about linked genes is correct?

Accepted Answer

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

Question 11

A woman is a carrier for a sex-linked recessive disorder (X-linked). If she has children with a man who does not have the disorder, what is the probability that their son will have the disorder?

Accepted Answer

$$0.5$$

Question 12

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple traits.

Question 13

In a population, the recombination frequency between two genes is $$10\%. $$What does this indicate about the physical distance between these genes on a chromosome?

Accepted Answer

They are close together on the same chromosome.

Question 14

Which of the following genotypes represents a carrier for a recessive genetic disorder?

Accepted Answer

Aa

Question 15

A man with type B blood ($$I^B i) $$has a child with a woman with type O blood ($$ii). $$What is the probability that their child will have type O blood?

Accepted Answer

$$0.5$$

Question 16

Which of the following best describes codominance?

Accepted Answer

Both alleles are fully expressed in the phenotype.

Question 17

A geneticist is mapping genes and finds that two genes have a recombination frequency of $$50\%. $$What does this most likely indicate?

Accepted Answer

The genes are on different chromosomes or far apart on the same chromosome.

Question 18

Which of the following is an example of a multiallelic system in humans?

Accepted Answer

ABO blood group

Question 19

If a trait is controlled by multiple genes, each contributing to the phenotype, which inheritance pattern does this describe?

Accepted Answer

Polygenic inheritance

Question 20

A pedigree shows that only males are affected by a certain trait, and the trait is never passed from father to son. What is the most likely mode of inheritance?

Accepted Answer

X-linked recessive

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