Question 1

In diploid species, diploid cells may undergo either mitosis or meiosis. Haploid cells may undergo mitosis (for certain species) but not meiosis because:

Accepted Answer

homologous chromosomes cannot pair.

Question 2

Which of the following best describes the difference between a character and a trait as used in Mendelian genetics?

Accepted Answer

A character is a heritable feature, while a trait is a specific variant of that feature.

Question 3

A plant with genotype PpYy is crossed with another plant of the same genotype. What is the probability that an offspring will have the genotype ppYY? (Assume independent assortment.)

Accepted Answer

$\frac{1}{16}$

Question 4

Which of the following scenarios best illustrates the law of independent assortment?

Accepted Answer

A plant with genotype RrYy produces gametes with all possible combinations of R, r, Y, and y alleles.

Question 5

In a testcross, an individual with the dominant phenotype is crossed with a homozygous recessive individual. If any offspring display the recessive phenotype, what can you conclude about the genotype of the mystery parent?

Accepted Answer

It must be heterozygous.

Question 6

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 7

A woman with blood type AB has a child with a man who is blood type O. What are the possible blood types of their children?

Accepted Answer

A or B

Question 8

Which of the following best describes pleiotropy?

Accepted Answer

One gene affects multiple phenotypic traits.

Question 9

A couple, both carriers for cystic fibrosis (a recessive disorder), want to know the probability that their first two children will both be unaffected. What is the probability?

Accepted Answer

$\frac{9}{16}$

Question 10

Which of the following statements about dominant alleles is correct?

Accepted Answer

Dominant alleles are not necessarily more common than recessive alleles.

Question 11

In Tay-Sachs disease, the allele is considered recessive at the organismal level, but at the molecular level, the alleles are:

Accepted Answer

codominant.

Question 12

Which of the following best explains why consanguineous (close-relative) marriages increase the risk of recessive genetic disorders?

Accepted Answer

Close relatives are more likely to share the same rare recessive alleles.

Question 13

A genetic counselor is working with a couple, both of whom have a sibling who died from a recessive genetic disorder. If neither parent has the disorder, what is the probability that their first child will have the disorder? (Assume both sets of parents are carriers.)

Accepted Answer

$\frac{1}{16}$

Question 14

Which of the following is an example of polygenic inheritance?

Accepted Answer

Human skin color, which is controlled by several genes.

Question 15

If a plant with genotype TtAa is crossed with a plant with genotype ttaa, what proportion of the offspring will have tall stems and terminal flowers? (T = tall, t = dwarf; A = axial, a = terminal)

Accepted Answer

$\frac{1}{4}$

Question 16

Which of the following best describes the law of segregation?

Accepted Answer

The two alleles for a heritable character separate during gamete formation.

Question 17

A man with Huntington's disease (a dominant disorder) has a child with a woman who does not have the disease. What is the probability that their child will have Huntington's disease if the man is heterozygous?

Accepted Answer

$\frac{1}{2}$

Question 18

Which of the following is true about normal gametes produced from one meiotic event?

Accepted Answer

Each has the same chromosome number.

Question 19

Which of the following is an example of epistasis?

Accepted Answer

A gene for pigment deposition masks the expression of a gene for pigment color in Labrador retrievers.

Mendelian Genetics: Principles, Patterns, and Extensions

Study Guide - Practice Questions

Study Guide - Flashcards