Question 1

Which of the following best explains why Mendel chose pea plants for his genetic experiments?

Accepted Answer

Pea plants have several polymorphic traits and can be easily cross-pollinated or self-pollinated.

Question 2

In Mendel's monohybrid cross between true-breeding purple-flowered and white-flowered pea plants, what was the phenotypic ratio observed in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

If a pea plant with genotype $$Rr ($$round seeds) is self-pollinated, what is the expected genotypic ratio among the offspring?

Accepted Answer

$$1:2:1 (RR$$:Rr:rr)

Question 4

Which of the following statements about alleles is correct?

Accepted Answer

Alleles are different versions of a gene found at the same locus on homologous chromosomes.

Question 5

A testcross is performed between a pea plant with an unknown genotype for seed shape (dominant phenotype) and a homozygous recessive plant. If all offspring have round seeds, what is the genotype of the unknown parent?

Accepted Answer

Homozygous dominant ($$RR)$$

Question 6

Which principle states that alleles of different genes are transmitted independently of one another during gamete formation?

Accepted Answer

Law of Independent Assortment

Question 7

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

Accepted Answer

$$9:3:3:1$$

Question 8

A woman with blood type AB ($$I^A I^B) $$and a man with blood type O ($$ii) $$have a child. What are the possible blood types of their child?

Accepted Answer

A or B

Question 9

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 10

Which genetic phenomenon is illustrated when a single gene affects multiple phenotypic traits, such as in Marfan syndrome?

Accepted Answer

Pleiotropy

Question 11

In mice, coat color is determined by two genes: one gene determines pigment color (B = black, b = brown), and another gene determines whether pigment is deposited (C = color, c = no color). What is the expected phenotypic ratio in the F2 generation from a cross between two $$BbCc$$ mice?

Accepted Answer

$$9$$ black: $$3$$ brown: $$4$$ white

Question 12

Which of the following best describes codominance?

Accepted Answer

Both alleles in a heterozygote are fully expressed, resulting in a phenotype that shows both traits distinctly.

Question 13

A man with genotype $$X^wY ($$white-eyed) and a woman with genotype $$X^WX^w ($$red-eyed) have children. What is the probability that a son will have white eyes?

Accepted Answer

$$0.5$$

Question 14

Which of the following is true regarding linked genes?

Accepted Answer

Linked genes are located on the same chromosome and tend to be inherited together.

Question 15

If two genes are located far apart on the same chromosome, what is most likely to occur during meiosis?

Accepted Answer

Crossing over will occur frequently between them, increasing recombinant offspring.

Question 16

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes contribute additively to a single phenotypic trait.

Question 17

A plant with genotype $$Pp ($$purple flowers) is crossed with a plant with genotype $$pp ($$white flowers). What is the probability that an offspring will have purple flowers?

Accepted Answer

$$0.5$$

Question 18

Which of the following is an example of epistasis?

Accepted Answer

A gene at one locus affects the expression of a gene at another locus, such as pigment deposition in mouse fur.

Question 19

Which of the following statements about Mendel’s law of segregation is correct?

Accepted Answer

Each gamete receives only one allele of each gene from each parent.

Question 20

Which of the following best explains why the relationship between genotype and phenotype is not always straightforward?

Accepted Answer

Many traits are influenced by multiple genes and environmental factors.

Mendelian Genetics: Principles and Extensions

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