Q: If two heterozygous black pigs (Bb) are crossed, what is the probability that their first two offspring will both have black skin?

$$\frac{3}{4} \times \frac{3}{4} = \frac{9}{16}$$

Q: In a family with three children, what is the probability that two will be boys and one will be a girl? (Assume $$p = \frac{1}{2}$$ for a boy and $$q = \frac{1}{2}$$ for a girl.)

$$3 \times (\frac{1}{2})^2$ \times (\frac{1}{2}) = \frac{3}{8}$$

Q: If a plant with genotype Gg is self-fertilized, what is the probability that, in a pod with six seeds, exactly four will be yellow and two will be green? ($$p = \frac{3}{4}$$ for yellow, $$q = \frac{1}{4}$$ for green)

$$15 \times (\frac{3}{4})^4$ \times (\frac{1}{4})^2$

Question 1

Which of the following best describes Mendel’s theory of particulate inheritance?

Accepted Answer

Each parent contributes a single, indivisible hereditary unit for each trait, which remain distinct across generations.

Question 2

A cross between two heterozygous pea plants for seed color (Gg × Gg) produces what expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1 ($$yellow:green)

Question 3

Which of the following experimental innovations was NOT a critical feature of Mendel’s success?

Accepted Answer

Allowing plants to cross-pollinate randomly without control

Question 4

In a dihybrid cross between two heterozygous plants (RrGg × RrGg), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 5

If two heterozygous black pigs (Bb) are crossed, what is the probability that their first two offspring will both have black skin?

Accepted Answer

$$\frac{3}{4} 	imes \frac{3}{4} = \frac{9}{16}$$

Question 6

Which rule of probability is used to calculate the likelihood of two independent genetic events occurring together?

Accepted Answer

Product rule

Question 7

A test cross is performed between a plant with genotype Rr and a plant with genotype rr. What is the expected ratio of round to wrinkled seeds in the progeny?

Accepted Answer

$$1:1$$

Question 8

Which of the following is a key feature of autosomal dominant inheritance in human pedigrees?

Accepted Answer

Both males and females are affected with equal frequency.

Question 9

In a family with three children, what is the probability that two will be boys and one will be a girl? (Assume $$p = \frac{1}{2}$$ for a boy and $$q = \frac{1}{2}$$ for a girl.)

Accepted Answer

$$3 	imes (\frac{1}{2})^2$ 	imes (\frac{1}{2}) = \frac{3}{8}$$

Question 10

A chi-square test is performed on a genetic cross with 3 outcome classes. What is the degrees of freedom (df) for this test?

Accepted Answer

$$df = 3 - 1 = 2$$

Question 11

Which molecular mechanism explains the wrinkled seed phenotype in Mendel’s peas?

Accepted Answer

A loss-of-function mutation in the Sbe1 gene prevents the production of amylopectin.

Question 12

Which of the following is NOT a characteristic of autosomal recessive inheritance?

Accepted Answer

Every affected individual must have at least one affected parent.

Question 13

If a plant with genotype Gg is self-fertilized, what is the probability that, in a pod with six seeds, exactly four will be yellow and two will be green? ($$p = \frac{3}{4}$$ for yellow, $$q = \frac{1}{4}$$ for green)

Accepted Answer

$$15 	imes (\frac{3}{4})^4$ 	imes (\frac{1}{4})^2$

Question 14

Which of the following best describes the molecular basis for the tall phenotype in pea plants?

Accepted Answer

The Le gene produces a functional gibberellin 3β-hydroxylase enzyme, allowing normal gibberellin synthesis.

Question 15

A pedigree shows a trait that appears in every generation, affects both males and females, and is transmitted by both genders. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 16

Which of the following is a correct application of the sum rule in probability?

Accepted Answer

Calculating the probability of pulling either a red or a blue marble from a bag by adding their individual probabilities.

Question 17

In a cross between two Manx cats (Mm × Mm), where MM is normal, Mm is Manx, and mm is lethal, what fraction of the surviving kittens are expected to be Manx?

Accepted Answer

$$\frac{2}{3}$$

Question 18

Which of the following statements about Mendel’s laws is correct?

Accepted Answer

The law of segregation states that alleles for a trait separate during gamete formation.

Transmission Genetics: Mendelian Principles, Probability, and Pedigree Analysis

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