Question 1

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

Accepted Answer

Paired alleles separate during gamete formation, so each gamete receives only one allele for each gene.

Question 2

A pea plant with genotype Tt is crossed with another Tt plant. What is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

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

Accepted Answer

$$9:3:3:1$$

Question 4

Which of the following is a correct application of the forked-line (branch) method in a trihybrid cross (AaBbCc x AaBbCc)?

Accepted Answer

Calculate the probability for each trait separately and multiply the probabilities for combined outcomes.

Question 5

A testcross is performed between a plant with an unknown genotype and a homozygous recessive plant. If all offspring display the dominant phenotype, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant

Question 6

Which of the following best explains why crossing over during meiosis increases genetic variation?

Accepted Answer

It allows homologous chromosomes to exchange segments, creating new allele combinations.

Question 7

Given the observed offspring numbers from a monohybrid cross: 75 tall and 25 short (expected 3:1 ratio), calculate the chi-square value ($$\$$chi^2$$).

Accepted Answer

$$\$$chi^2$$ = 0$$

Question 8

Which pedigree pattern suggests an X-linked dominant trait?

Accepted Answer

All daughters of an affected male have the trait, but none of his sons do.

Question 9

If a plant with genotype AaBb is self-crossed, what is the probability of obtaining an offspring with genotype aabb?

Accepted Answer

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

Question 10

Which of the following statements about Mendel’s model organism (pea plants) is FALSE?

Accepted Answer

They can only reproduce by cross-fertilization.

Question 11

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

Accepted Answer

Autosomal dominant

Question 12

Which of the following best defines a genotype?

Accepted Answer

The combination of alleles that code for a specific trait

Question 13

In a dihybrid cross, what is the probability of producing an offspring that is homozygous recessive for both traits (rryy) from two RrYy parents?

Accepted Answer

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

Question 14

Which of the following is NOT a postulate of Mendel’s model?

Accepted Answer

Genes are always inherited together as a group.

Question 15

A woman who is a carrier for an X-linked recessive trait has children with a man who does not have the trait. What is the probability that their son will express the trait?

Accepted Answer

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

Question 16

Which of the following best describes the purpose of a chi-square test in genetics?

Accepted Answer

To assess whether observed offspring ratios match expected Mendelian ratios

Question 17

If a pedigree shows a trait that skips generations and affects more males than females, what is the most likely mode of inheritance?

Accepted Answer

X-linked recessive

Question 18

Which of the following is a real-world example of independent assortment?

Accepted Answer

A child inherits brown eyes from one parent and curly hair from the other, regardless of the combination in the parents.

Question 19

In a cross between two heterozygous individuals (Bb x Bb), what is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:2:1$$

Question 20

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are alternative forms of a single gene.

Mendelian Genetics: Principles, Crosses, and Human Inheritance Patterns

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