Question 1

Gregor Mendel is considered the father of genetics because he:

Accepted Answer

Demonstrated that traits are inherited in discrete units through experiments with pea plants.

Question 2

In Mendel's first experiment, he crossed true-breeding purple-flowered pea plants with true-breeding white-flowered pea plants. All offspring in the F1 generation had purple flowers. What does this result demonstrate?

Accepted Answer

Purple is dominant to white.

Question 3

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 tall to short plants in the F2 generation?

Accepted Answer

$$3:1$$

Question 4

Which of the following best describes a 'test cross'?

Accepted Answer

Crossing an individual with a dominant phenotype but unknown genotype with a homozygous recessive individual.

Question 5

Mendel's Law of Independent Assortment states that:

Accepted Answer

Each pair of alleles segregates independently of other pairs during gamete formation.

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 7

A woman who is a carrier for a recessive X-linked disorder (genotype $$X^N X^n) $$and a man who is unaffected ($$X^N Y) $$have a child. What is the probability that their son will have the disorder?

Accepted Answer

$$0.25$$

Question 8

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple traits.

Question 9

In a dihybrid cross between two individuals heterozygous for both traits ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio if the genes assort independently?

Accepted Answer

$$9:3:3:1$$

Question 10

Which of the following is an example of codominance?

Accepted Answer

A person with type AB blood expressing both A and B antigens.

Question 11

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

Accepted Answer

A, B, AB, or O

Question 12

Which of the following statements about polygenic inheritance is correct?

Accepted Answer

It is responsible for quantitative traits such as human height.

Question 13

If a gene is located on the X chromosome and shows recessive inheritance, which of the following is true?

Accepted Answer

Males are more likely to express the trait than females.

Question 14

Which of the following best describes the Law of Segregation?

Accepted Answer

Alleles separate during gamete formation so each gamete carries only one allele for each gene.

Question 15

A geneticist observes that two genes are inherited together more often than expected by chance. This is most likely due to:

Accepted Answer

Linkage.

Question 16

Which of the following is an example of environmental influence on phenotype?

Accepted Answer

Identical twins with different skin colors due to sun exposure.

Question 17

A woman with genotype $$X^N X^n ($$carrier for color blindness) and a man with genotype $$X^N Y$$ have a daughter. What is the probability that the daughter will be color blind?

Accepted Answer

$$0$$

Question 18

Which of the following terms describes an individual with two identical alleles for a gene?

Accepted Answer

Homozygous

Question 19

A couple has a child with Marfan syndrome, a disorder caused by a dominant allele. Neither parent shows symptoms. What is the most likely explanation?

Accepted Answer

The disorder is caused by a new mutation in the child.

Question 20

Which of the following best explains why a test cross is used in genetics?

Accepted Answer

To determine the genotype of an individual with a dominant phenotype.

Mendelian Genetics and Patterns of Inheritance: Study Guide

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