Question 1

Which of Mendel’s postulates is best explained by the separation of homologous chromosomes during the first meiotic division?

Accepted Answer

Segregation

Question 2

A heterozygous tall pea plant (Tt) is crossed with a homozygous dwarf plant (tt). What is the expected phenotypic ratio in the offspring?

Accepted Answer

1 tall : 1 dwarf

Question 3

In a dihybrid cross between two plants heterozygous for both seed color (Yy) and seed shape (Rr), what is the probability of obtaining an offspring with yellow, round seeds?

Accepted Answer

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

Question 4

Which rule would you use to calculate the probability of obtaining either a heterozygous or a homozygous dominant individual in a monohybrid cross?

Accepted Answer

Sum rule

Question 5

If a couple has three children, what is the probability that exactly two of them are boys? (Assume the probability of a boy or girl is equal.)

Accepted Answer

$$\frac{3}{8}$$

Question 6

A test cross is performed to determine the genotype of a tall pea plant. If all offspring are tall, what is the genotype of the parent plant?

Accepted Answer

Homozygous dominant

Question 7

How many different types of gametes can be produced by an individual with the genotype AaBbCc?

Accepted Answer

8

Question 8

Which of the following best describes the chromosome theory of inheritance?

Accepted Answer

Genes are located on chromosomes and segregate during meiosis.

Question 9

In a cross between AaBb x AaBb, what is the probability of obtaining an offspring with the genotype aabb?

Accepted Answer

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

Question 10

Which of the following is an assumption of Mendel’s laws that may not always hold true in real populations?

Accepted Answer

Genes assort independently

Question 11

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 12

What is the probability that a plant heterozygous for a single gene (Aa) will produce a homozygous recessive offspring when crossed with another heterozygote?

Accepted Answer

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

Question 13

Which formula would you use to calculate the number of possible genotypes produced in a cross between two individuals heterozygous for n gene pairs?

Accepted Answer

$$3^n$$

Question 14

In a trihybrid cross (AaBbCc x AaBbCc), what is the probability of obtaining an offspring with the genotype AABbcc?

Accepted Answer

$$\frac{1}{32}$$

Question 15

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

Accepted Answer

The probability of two independent events occurring together is the product of their individual probabilities.

Question 16

A family has four children. What is the probability that exactly two are boys and two are girls?

Accepted Answer

$$\frac{6}{16}$$

Question 17

Which cytological process corresponds to Mendel’s law of independent assortment?

Accepted Answer

Random alignment of homologous chromosomes during metaphase I

Question 18

If the probability of a plant being tall is $$\frac{3}{4}$$ and the probability of it being yellow is $$\frac{3}{4}$$, what is the probability that a plant is both tall and yellow (assuming independent assortment)?

Accepted Answer

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

Question 19

Which of the following is a key assumption when using the binomial theorem in genetics?

Accepted Answer

Each trial is independent and has only two possible outcomes.

Mendelian Genetics: Principles, Crosses, and Probability

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