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 alleles during gamete formation?

Accepted Answer

Two members of each gene pair separate into different gametes.

Question 3

A plant with genotype $$Rr is $$crossed with a plant with genotype $$rr. $$What is the expected phenotypic ratio of the offspring if $$R is $$dominant to $$r$$?

Accepted Answer

$$1:1 ($$half dominant phenotype, half recessive phenotype)

Question 4

Which of the following scenarios demonstrates the principle of independent assortment?

Accepted Answer

Alleles for seed shape and seed color are transmitted independently because they are on different chromosomes.

Question 5

In a dihybrid cross between two heterozygotes ($$RrYy 	imes RrYy$$), what is the expected phenotypic ratio of the offspring?

Accepted Answer

$$9:3:3:1$$

Question 6

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

Accepted Answer

Homozygous dominant

Question 7

Which of the following best describes the phenomenon of linkage?

Accepted Answer

Genes located close together on the same chromosome tend to be inherited together.

Question 8

If two genes are far apart on the same chromosome, what is the expected frequency of crossing over between them?

Accepted Answer

High frequency, because crossing over is more likely.

Question 9

Which of the following is an example of codominance?

Accepted Answer

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

Question 10

A cross between a red-flowered plant ($$RR) $$and a white-flowered plant ($$rr) $$produces all pink-flowered offspring ($$Rr). $$What type of inheritance is this?

Accepted Answer

Incomplete dominance

Question 11

Which of the following statements about quantitative traits is correct?

Accepted Answer

They result from the combined effect of many genes and often show a bell-shaped distribution.

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 explains why environmental factors can influence phenotypes?

Accepted Answer

Environmental factors can interact with genes to shape the phenotype.

Question 14

A woman with type AB blood and a man with type O blood have a child. What are the possible blood types for their child?

Accepted Answer

A or B

Question 15

Which of the following is true about X-linked recessive traits?

Accepted Answer

They affect males more frequently than females.

Question 16

If a trait is controlled by multiple alleles, which of the following is true?

Accepted Answer

There may be more than two alleles for the gene in the population, but each individual has only two.

Question 17

A genetic map is constructed by analyzing which of the following?

Accepted Answer

The frequency of recombinant offspring between genes

Question 18

Which of the following best describes the outcome of a monohybrid cross between two heterozygotes ($$Rr 	imes Rr$$)?

Accepted Answer

The phenotypic ratio will be $$3:1 ($$dominant:recessive).

Question 19

Which of the following is a key difference between autosomal dominant and autosomal recessive inheritance patterns in pedigrees?

Accepted Answer

Autosomal dominant traits appear in every generation, while autosomal recessive traits may skip generations.

Mendel and the Gene: Foundations and Extensions of Mendelian Genetics

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