Q: Which equation represents the product law of probability for two independent events, A and B?

$$P(A \text{ and } B) = P(A) \times P(B)$$

Question 1

Which of Mendel's postulates explains why offspring inherit one allele from each parent for a given trait?

Accepted Answer

Segregation

Question 2

In a monohybrid cross between two heterozygous tall pea plants ($$D d 	imes D d$$), what is the expected phenotypic ratio in the $$F_2$$ generation?

Accepted Answer

$$3:1 ($$tall:dwarf)

Question 3

A testcross is performed between a tall pea plant and a homozygous dwarf plant. If the tall plant is heterozygous, what will be the expected outcome?

Accepted Answer

Half of the offspring will be tall and half will be dwarf

Question 4

What is the probability of obtaining a plant with yellow, round seeds in the $$F_2$$ generation of a dihybrid cross ($$Y y R r 	imes Y y R r$$)?

Accepted Answer

$$9/16$$

Question 5

Which of the following best describes Mendel’s fourth postulate, the law of independent assortment?

Accepted Answer

Alleles for different traits segregate independently during gamete formation

Question 6

If an organism has a genotype $$A a B b C c$$, how many different types of gametes can it produce due to independent assortment?

Accepted Answer

$$8$$

Question 7

In a trihybrid cross ($$A a B b C c 	imes A a B b C c$$), what is the probability of obtaining an offspring with the dominant phenotype for all three traits?

Accepted Answer

$$27/64$$

Question 8

Which method is most efficient for predicting phenotypic ratios in crosses involving more than two gene pairs?

Accepted Answer

Forked-line method

Question 9

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

Accepted Answer

Autosomal dominant

Question 10

Tay–Sachs disease is caused by a mutation in the gene encoding Hex-A. Which statement is true about the inheritance of this disorder?

Accepted Answer

One wild-type allele is sufficient for normal development

Question 11

In a dihybrid cross, what is the expected phenotypic ratio for the $$F_2$$ generation if both traits assort independently?

Accepted Answer

$$9:3:3:1$$

Question 12

If a pedigree shows a trait that skips generations and appears equally in both sexes, what is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 13

What is the probability of obtaining a plant with green, wrinkled seeds in the $$F_2$$ generation of a dihybrid cross ($$Y y R r 	imes Y y R r$$)?

Accepted Answer

$$1/16$$

Question 14

Which of the following best describes a heterozygous genotype?

Accepted Answer

Two different alleles for a trait

Question 15

In Mendel’s experiments, what was the result when he crossed true-breeding tall and dwarf pea plants?

Accepted Answer

All offspring were tall

Question 16

Which equation represents the product law of probability for two independent events, A and B?

Accepted Answer

$$P(A 	ext{ and } B) = P(A) 	imes P(B)$$

Question 17

How many possible gametes can a human produce due to independent assortment, given $$n = 23$$?

Accepted Answer

$$2^{23}$$

Question 18

Which of the following is NOT a convention used in pedigree analysis?

Accepted Answer

Triangles represent twins

Question 19

A coin toss is used to illustrate the product law. What is the probability of getting heads on both a penny and a nickel?

Accepted Answer

$$1/4$$

Question 20

Which statement about Mendel’s ratios is correct?

Accepted Answer

They are hypothetical predictions based on certain assumptions

Ch 3 Mendelian Genetics: Principles, Crosses, and Pedigree Analysis

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