Q: Which equation would you use to calculate the probability of obtaining a yellow, wrinkled pea from a dihybrid cross (RrGg x RrGg)?

$$P(\text{yellow, wrinkled}) = P(G-) \times P(rr)$$

Question 1

Which feature of Mendel’s experimental design was most critical in allowing him to discover the basic principles of genetic transmission?

Accepted Answer

He selected traits with only two easily distinguishable forms.

Question 2

In a monohybrid cross between two heterozygous pea plants (Yy x Yy), what is the expected genotypic ratio in the F2 generation?

Accepted Answer

$$1:2:1 (YY$$:Yy:yy)

Question 3

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

Accepted Answer

The two alleles for a gene separate during gamete formation, and each gamete receives one allele.

Question 4

A test cross is performed between a pea plant with yellow seeds of unknown genotype and a plant with green seeds (yy). If all offspring have yellow seeds, what is the genotype of the yellow-seeded parent?

Accepted Answer

YY

Question 5

In a dihybrid cross (RrGg x RrGg), what is the probability of obtaining an offspring with the genotype rrgg?

Accepted Answer

$$1/16$$

Question 6

Which of the following statements about dominant and recessive alleles is correct?

Accepted Answer

A dominant allele always masks the effect of a recessive allele in a heterozygote.

Question 7

If a plant with genotype Rr is self-crossed, what proportion of the round-seeded F2 offspring are expected to be heterozygous?

Accepted Answer

$$2/3$$

Question 8

A researcher observes a 9:3:3:1 phenotypic ratio in the F2 generation of a cross. What does this indicate about the genes involved?

Accepted Answer

The genes assort independently.

Question 9

Which equation would you use to calculate the probability of obtaining a yellow, wrinkled pea from a dihybrid cross (RrGg x RrGg)?

Accepted Answer

$$P(	ext{yellow, wrinkled}) = P(G-) 	imes P(rr)$$

Question 10

In a test cross between a heterozygous tall pea plant (Tt) and a homozygous recessive short plant (tt), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$1:1 ($$tall:short)

Question 11

A plant breeder wants to determine if a purple-flowered pea plant is homozygous or heterozygous. Which cross should they perform?

Accepted Answer

Cross with a white-flowered plant (pp)

Question 12

Which of the following best explains why Mendel’s results rejected the blending theory of heredity?

Accepted Answer

Parental traits reappeared unchanged in the F2 generation.

Question 13

If a plant with genotype Yy is crossed with a plant with genotype yy, what proportion of the offspring will display the dominant phenotype?

Accepted Answer

$$1/2$$

Question 14

Which of the following is an example of a reciprocal cross?

Accepted Answer

Crossing a male with genotype AA with a female with genotype aa, and then crossing a male with genotype aa with a female with genotype AA.

Question 15

In a trihybrid cross (RrGgWw x RrGgWw), what is the probability of obtaining an offspring that is homozygous recessive for all three traits?

Accepted Answer

$$1/64$$

Question 16

Which of the following best describes a pure-breeding line?

Accepted Answer

A population that always produces offspring with the same phenotype when self-crossed.

Question 17

A chi-square test is used in genetics to:

Accepted Answer

Test the fit between observed and expected outcomes.

Question 18

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

Accepted Answer

They are the only plants with genes.

Question 19

If two genes assort independently, what is the probability of obtaining an offspring that is heterozygous for both genes in a dihybrid cross (RrGg x RrGg)?

Accepted Answer

$$4/16$$

Question 20

Which of the following best describes the sum rule in probability as applied to genetics?

Accepted Answer

The probability of either of two mutually exclusive events occurring is the sum of their individual probabilities.

CH 2 transmission genetics & medel NEW SEM

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