Question 1

Which of the following best explains why Mendel chose the garden pea as his model organism for genetic experiments?

Accepted Answer

Peas produce large numbers of seeds, have a short generation time, and allow controlled matings.

Question 2

According to Mendel’s principle of segregation, what happens to the two alleles for a gene during gamete formation?

Accepted Answer

They segregate so that each gamete receives only one allele.

Question 3

A plant with genotype RrYy is crossed with a plant with genotype rryy. What is the expected phenotypic ratio among the offspring if the genes assort independently?

Accepted Answer

$$1:1:1:1$$

Question 4

Which of the following scenarios best illustrates the concept of a testcross?

Accepted Answer

Crossing an individual with a dominant phenotype but unknown genotype with a homozygous recessive individual.

Question 5

Which of the following best describes the principle of independent assortment?

Accepted Answer

Alleles of different genes segregate independently during gamete formation if they are on different chromosomes.

Question 6

If two genes are located close together on the same chromosome, which of the following is most likely to occur?

Accepted Answer

They will be inherited together more often than not, a phenomenon known as linkage.

Question 7

A geneticist observes that two genes have a recombination frequency of 10%. What does this indicate about their physical distance on a chromosome?

Accepted Answer

They are likely to be 10 map units apart.

Question 8

Which of the following is an example of codominance in humans?

Accepted Answer

A person with type AB blood expressing both A and B antigens on red blood cells.

Question 9

In snapdragons, red flowers (RR) crossed with white flowers (rr) produce pink flowers (Rr). What type of inheritance is this?

Accepted Answer

Incomplete dominance

Question 10

A trait that shows a continuous range of phenotypes, such as human height, is most likely controlled by:

Accepted Answer

Multiple genes (polygenic inheritance)

Question 11

Which of the following statements about environmental effects on phenotype is correct?

Accepted Answer

Environmental factors can influence the expression of genetic traits.

Question 12

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 13

Which of the following best describes an X-linked recessive trait?

Accepted Answer

It affects males more frequently than females and can skip generations.

Question 14

If a woman with blood type AB has children with a man with blood type O, what are the possible blood types of their children?

Accepted Answer

A and B only

Question 15

Which of the following is a correct statement about multiple allelism?

Accepted Answer

A gene can have more than two alleles in a population.

Question 16

A genetic map is constructed using which of the following data?

Accepted Answer

The frequency of recombinant offspring from genetic crosses.

Question 17

Which of the following best explains why quantitative traits often show a bell-shaped distribution in a population?

Accepted Answer

They are influenced by many genes and environmental factors.

Question 18

A man with an X-linked dominant disorder has children with a woman who does not have the disorder. Which of the following is true about their offspring?

Accepted Answer

All daughters will have the disorder, but none of the sons will.

Question 19

Which of the following is NOT a reason Mendel’s pea plant experiments were successful?

Accepted Answer

Pea plants produced a small number of seeds per cross.

Question 20

If a trait is autosomal recessive, which of the following is most likely to be true?

Accepted Answer

Affected individuals can have unaffected parents who are both carriers.

Chapter 14-Mendel and the Gene: Principles of Inheritance and Extensions

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