Question 1

Which of the following best describes Mendel’s law of segregation?

Accepted Answer

Each individual has two alleles for each gene, and these alleles separate during gamete formation so that each gamete receives only one allele.

Question 2

A pea plant with genotype Yy is crossed with another Yy plant. What is the expected phenotypic ratio of yellow to green seeds in the offspring?

Accepted Answer

$$3:1$$

Question 3

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

Accepted Answer

Each affected individual has at least one affected parent.

Question 4

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

Accepted Answer

$$9:3:3:1$$

Question 5

A test cross is performed between a plant with an unknown genotype for a dominant trait 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 the molecular basis for the wrinkled seed phenotype in Mendel’s peas?

Accepted Answer

A dominant allele produces a starch-branching enzyme, while the recessive allele results in a loss of enzyme function due to an insertion mutation.

Question 7

If a plant heterozygous for four unlinked genes (AaBbDdEe) is selfed, what proportion of the progeny will be genotypically AaBBddEe?

Accepted Answer

$$\frac{1}{64}$$

Question 8

Which probability rule would you use to determine the likelihood of obtaining a pea plant with yellow seeds and round shape from a dihybrid cross?

Accepted Answer

Product rule

Question 9

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

Accepted Answer

Autosomal dominant

Question 10

Which of the following statements about Mendel’s experimental approach is FALSE?

Accepted Answer

He did not quantify his results, relying only on qualitative observations.

Question 11

A plant with genotype GgRr is test-crossed (crossed with ggrr). What phenotype ratios are expected among the progeny?

Accepted Answer

$$1:1:1:1$$

Question 12

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

Accepted Answer

Each affected individual must have at least one affected parent.

Question 13

Which equation represents the chi-square statistic used to compare observed and expected genetic ratios?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O - E)^2$}{E}$$

Question 14

A cross between two plants produces offspring in a 3:1 ratio for a particular trait. What is the most likely genotype of the parents?

Accepted Answer

Both parents are heterozygous.

Question 15

Which molecular event causes the green seed phenotype in Mendel’s peas?

Accepted Answer

A mutant allele blocks the breakdown of chlorophyll, causing seeds to remain green.

Question 16

If the probability of rolling a 2 on a single die is $$\frac{1}{6}$$, what is the probability of rolling a 2 or a 5?

Accepted Answer

$$\frac{1}{3}$$

Question 17

Which of the following best describes a heterozygous genotype?

Accepted Answer

An individual with two different alleles for a gene.

Question 18

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

Accepted Answer

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

Question 19

Which of the following is NOT one of Mendel’s four postulates?

Accepted Answer

Dominant alleles are always more common in the population.

Transmission Genetics: Mendelian Principles and Probability in Genetic Analysis

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