Q: Which of the following crosses would produce a 1:2:1 genotypic ratio in the offspring?

Heterozygote $$\times$$ heterozygote

Question 1

Which of the following best describes the difference between dominant and recessive alleles?

Accepted Answer

Dominant alleles mask the expression of recessive alleles in heterozygotes.

Question 2

A plant with genotype $$Tt ($$where $$T is $$tall and $$t is $$short) is crossed with another $$Tt$$ plant. What is the expected phenotypic ratio of their offspring?

Accepted Answer

3 tall : 1 short

Question 3

Which of the following best defines a homozygous genotype?

Accepted Answer

An individual with two identical alleles for a gene

Question 4

In a cross between two heterozygous individuals ($$Aa 	imes Aa$$), what is the probability of producing an offspring that is homozygous recessive?

Accepted Answer

$$\frac{1}{4}$$

Question 5

Which of the following is an example of codominance in humans?

Accepted Answer

ABO blood group system

Question 6

A woman with blood type $$AB$$ and a man with blood type $$O$$ have a child. What are the possible blood types of their child?

Accepted Answer

A or B

Question 7

Which of the following statements about sex-linked genes is correct?

Accepted Answer

They are found on the X or Y chromosomes.

Question 8

If a male is affected by a recessive X-linked disorder, what is the probability that his daughter will be a carrier if the mother is not a carrier?

Accepted Answer

0%

Question 9

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote displays a phenotype intermediate between the two homozygotes.

Question 10

A cross between a red-flowered plant ($$RR) $$and a white-flowered plant ($$WW) $$produces pink-flowered offspring ($$RW). $$What type of inheritance is this an example of?

Accepted Answer

Incomplete dominance

Question 11

Which Punnett square result would you expect from a cross between a homozygous dominant ($$AA) $$and a homozygous recessive ($$aa) $$individual?

Accepted Answer

All $$Aa$$

Question 12

A woman who is a carrier for hemophilia (an X-linked recessive disorder) and a normal man have a son. What is the probability that their son will have hemophilia?

Accepted Answer

$$\frac{1}{2}$$

Question 13

Which of the following best explains why males are more likely to express X-linked recessive traits?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will be expressed.

Question 14

If two parents are both heterozygous for a trait ($$Rr$$), what is the probability that their child will be homozygous dominant?

Accepted Answer

$$\frac{1}{4}$$

Question 15

Which of the following is NOT a possible genotype for a person with type A blood in the ABO blood group system?

Accepted Answer

$$ii$$

Question 16

A man with type AB blood and a woman with type O blood have children. What is the probability that a child will have type B blood?

Accepted Answer

$$0.5$$

Question 17

Which of the following crosses would produce a 1:2:1 genotypic ratio in the offspring?

Accepted Answer

Heterozygote $$	imes$$ heterozygote

Question 18

Which of the following best describes the genotype of an individual who is heterozygous for a gene?

Accepted Answer

Two different alleles

Question 19

Which of the following is an example of a sex-linked trait in humans?

Accepted Answer

Color blindness

Question 20

A geneticist is studying a trait that shows incomplete dominance. If a homozygous dominant individual is crossed with a homozygous recessive individual, what will the phenotype of the F1 generation be?

Accepted Answer

All show an intermediate phenotype

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