Question 1

Which of the following best describes Mendel’s Law of Segregation?

Accepted Answer

The two alleles for a heritable character separate during gamete formation and end up in different gametes.

Question 2

A pea plant with genotype $$Pp ($$purple flowers) is crossed with a plant with genotype $$pp ($$white flowers). What is the expected phenotypic ratio of the offspring?

Accepted Answer

1 purple : 1 white

Question 3

Which of the following is an example of a testcross?

Accepted Answer

Crossing a plant with an unknown genotype showing the dominant phenotype with a homozygous recessive plant

Question 4

If two heterozygous pea plants ($$Pp) $$are crossed, what is the probability that an offspring will have white flowers?

Accepted Answer

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

Question 5

Which statement about Mendel’s Law of Independent Assortment is correct?

Accepted Answer

It states that allele pairs segregate independently of each other during gamete formation.

Question 6

In a dihybrid cross between two plants with genotype $$YyRr$$, what is the probability of obtaining an offspring with genotype $$yyrr$$?

Accepted Answer

$$\frac{1}{16}$$

Question 7

A plant breeder wants to know if a purple-flowered pea plant is homozygous ($$PP) or $$heterozygous ($$Pp). $$Which cross should they perform to determine the genotype?

Accepted Answer

Cross with a homozygous recessive ($$pp) $$plant

Question 8

If the probability of a pea plant producing yellow seeds is $$\frac{3}{4}$$ and the probability of producing round seeds is $$\frac{3}{4}$$, what is the probability of producing a plant with both yellow and round seeds (assuming independent assortment)?

Accepted Answer

$$\frac{9}{16}$$

Question 9

Which of the following best explains why Mendel’s results were so reliable?

Accepted Answer

He counted large numbers of offspring and used quantitative analysis.

Question 10

A heterozygous plant ($$Pp) is $$self-fertilized. What is the expected genotypic ratio among the offspring?

Accepted Answer

1 PP : 2 Pp : 1 pp

Question 11

Which of the following is a phenotype?

Accepted Answer

Purple flowers

Question 12

If a plant with genotype $$Pp is $$crossed with a plant with genotype $$PP$$, what fraction of the offspring will be homozygous?

Accepted Answer

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

Question 13

Which of the following is NOT a reason why Mendel chose pea plants for his experiments?

Accepted Answer

They have a long generation time.

Question 14

A couple knows that both are carriers for a recessive genetic disorder. What is the probability that their child will be affected by the disorder?

Accepted Answer

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

Question 15

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype is the genetic makeup, phenotype is the observable trait.

Question 16

In a trihybrid cross ($$AaBbCc 	imes AaBbCc$$), what is the probability of obtaining an offspring with genotype $$aabbcc$$?

Accepted Answer

$$\frac{1}{64}$$

Question 17

Which of the following is an example of a homozygous genotype?

Accepted Answer

PP

Question 18

If two events are mutually exclusive, what is the probability that either event occurs?

Accepted Answer

$$P(A) + P(B)$$

Question 19

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are different versions of a gene found at the same locus.

Question 20

A plant with genotype $$YyRr is $$self-crossed. What is the probability of obtaining an offspring with yellow, wrinkled seeds (Y_rr)?

Accepted Answer

$$\frac{3}{16}$$

Mendel and the Gene Idea: Foundations of Classical Genetics

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