Question 1

Which of the following best describes the difference between the blending hypothesis and Mendel's particulate hypothesis of inheritance?

Accepted Answer

The blending hypothesis suggests that hereditary determinants mix together permanently in offspring, while the particulate hypothesis proposes that hereditary determinants remain discrete and unchanged from generation to generation.

Question 2

A true-breeding pea plant with round seeds (RR) is crossed with a true-breeding plant with wrinkled seeds (rr). What is the expected genotype and phenotype of the F1 generation?

Accepted Answer

All F1 plants will have genotype $$Rr$$ and round seeds.

Question 3

In a monohybrid cross between two heterozygous pea plants ($$Rr 	imes Rr$$), what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$3:1 ($$three round seeds to one wrinkled seed)

Question 4

Which of the following best explains Mendel's principle of segregation?

Accepted Answer

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

Question 5

A dihybrid cross between two pea plants heterozygous for both seed shape and seed color ($$RrYy 	imes RrYy) $$produces which expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 6

Which of the following scenarios is an example of codominance?

Accepted Answer

A person with genotype $$I^A I^B$$ for the ABO blood group expresses both A and B antigens on their red blood cells.

Question 7

Which of the following best describes pleiotropy?

Accepted Answer

A single gene influences multiple, seemingly unrelated phenotypic traits.

Question 8

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

Accepted Answer

$$RR$$

Question 9

Which of the following statements about dominant alleles is correct?

Accepted Answer

Dominant alleles are not necessarily more common in a population than recessive alleles.

Question 10

A geneticist is studying a trait in humans that shows a continuous range of phenotypes, such as height. Which genetic principle best explains this observation?

Accepted Answer

Polygenic inheritance, where multiple genes each contribute to the phenotype.

Question 11

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

Accepted Answer

Alleles of different genes are distributed independently of one another during gamete formation.

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 is an example of environmental influence on phenotype?

Accepted Answer

Individuals with phenylketonuria (PKU) develop normally if placed on a low-phenylalanine diet.

Question 14

In chickens, comb shape is determined by two genes. A cross between a rose comb and a pea comb produces all walnut comb offspring. This is an example of:

Accepted Answer

Epistasis

Question 15

If a gene has more than two alleles in a population, this is referred to as:

Accepted Answer

Multiple allelism

Question 16

Which of the following best explains why Mendel's use of model organisms (garden peas) was critical to his success in discovering the rules of inheritance?

Accepted Answer

Garden peas have easily recognizable traits, short reproductive cycles, and allow controlled matings.

Question 17

A cross between two pink-flowered snapdragons (incomplete dominance) produces offspring in what phenotypic ratio?

Accepted Answer

$$1$$ red : $$2$$ pink : $$1$$ white

Question 18

Which of the following best describes the chromosomal theory of inheritance?

Accepted Answer

Genes are located on chromosomes, and the behavior of chromosomes during meiosis explains inheritance patterns.

Question 19

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

Accepted Answer

Type A or Type B

Question 20

Which of the following is a real-world example of a quantitative trait?

Accepted Answer

Human height, which shows a continuous range of values in the population.

BIO181- 4.4: Mendelian Inheritance (Unit4: Growth and Inheritance)

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