Question 1

Gregor Mendel is often called the 'father of genetics.' What was remarkable about his experiments with pea plants?

Accepted Answer

He systematically cross-bred pea plants and used quantitative analysis to deduce the basic laws of inheritance.

Question 2

Why did Mendel choose garden pea plants for his genetic experiments?

Accepted Answer

They have a short generation time, produce many offspring, and have easily observable traits.

Question 3

Which of the following best defines an allele?

Accepted Answer

A variant form of a gene at a particular locus on a chromosome.

Question 4

If a plant with genotype $$YY is $$crossed with a plant with genotype $$yy$$, what will be the genotype of all F1 offspring?

Accepted Answer

$$Yy$$

Question 5

Which statement best describes the Law of Segregation?

Accepted Answer

Alleles for a trait separate during gamete formation, so each gamete carries only one allele for each gene.

Question 6

A testcross is performed between a plant with an unknown genotype showing the dominant phenotype and a homozygous recessive plant. 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 is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 8

In a dihybrid cross between two heterozygous individuals ($$RrYy 	imes RrYy$$), what is the expected phenotypic ratio of the offspring, assuming independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 9

Which of the following best describes pleiotropy?

Accepted Answer

A single gene affects multiple, seemingly unrelated phenotypic traits.

Question 10

If a gene has more than two alleles, such as the ABO blood group system, how does this affect the possible genotypes in a population?

Accepted Answer

It increases the number of possible genotypes.

Question 11

Which scenario is an example of polygenic inheritance?

Accepted Answer

Human skin color, which is influenced by several genes.

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 the difference between genotype and phenotype?

Accepted Answer

Genotype is the genetic makeup; phenotype is the observable physical or physiological traits.

Question 14

Which of the following is an example of codominance?

Accepted Answer

A person with type AB blood expresses both A and B antigens equally.

Question 15

Why does independent assortment not always apply to genes located close together on the same chromosome?

Accepted Answer

Because such genes tend to be inherited together due to genetic linkage.

Question 16

A genetic counselor is analyzing a pedigree for a rare inherited disease. How can pedigrees aid in genetic counseling?

Accepted Answer

They help predict the probability of offspring inheriting a genetic disorder.

Question 17

Which of the following best describes a true-breeding organism?

Accepted Answer

An organism that, when self-fertilized, produces offspring identical to itself for a given trait.

Question 18

In a Punnett square for a monohybrid cross between two heterozygotes ($$Aa 	imes Aa$$), what is the probability of producing an offspring with the recessive phenotype?

Accepted Answer

$$\frac{1}{4}$$

Question 19

Which of the following is an example of nature versus nurture influencing a trait?

Accepted Answer

Identical twins raised in different environments showing differences in intelligence.

Question 20

Which of the following best describes epistasis?

Accepted Answer

One gene affects the expression of another gene.

Genetics: Mendelian Principles and Patterns of Inheritance (Study Guide)

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