Question 1

Which of the following best describes Mendel's Law of Segregation?

Accepted Answer

Alleles for a character segregate during gamete formation, so each gamete carries only one allele for each gene.

Question 2

A pea plant with genotype $$Pp is $$crossed with another $$Pp$$ plant. What is the expected phenotypic ratio of their offspring?

Accepted Answer

3 purple : 1 white

Question 3

In Mendel's experiments, what is the significance of using true-breeding plants?

Accepted Answer

True-breeding plants produce offspring identical to themselves, ensuring consistent starting traits for crosses.

Question 4

Which equation represents the genotypic ratio for a monohybrid cross between two heterozygous individuals ($$Pp 	imes Pp$$)?

Accepted Answer

$$1\ PP : 2\ Pp : 1\ pp$$

Question 5

A testcross is performed between a plant with a dominant phenotype and a plant with a recessive phenotype. If the dominant plant is heterozygous, what is the expected outcome?

Accepted Answer

Half the offspring will show the dominant phenotype, and half will show the recessive phenotype.

Question 6

Which of the following best explains the Law of Independent Assortment?

Accepted Answer

Each pair of alleles segregates independently of other pairs during gamete formation.

Question 7

In a dihybrid cross ($$RrYy 	imes RrYy$$), what is the expected phenotypic ratio of the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 8

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink flowers.

Question 9

What is the genotype of a carrier for a recessively inherited disorder such as cystic fibrosis?

Accepted Answer

$$Cc$$

Question 10

Which of the following best describes pleiotropy?

Accepted Answer

One gene influences multiple phenotypic traits.

Question 11

A person with achondroplasia (dwarfism) has genotype $$Dd. If $$they have a child with a person of genotype $$dd$$, what is the probability that their child will have achondroplasia?

Accepted Answer

$$50\%$$

Question 12

Which of the following is true about codominance in human ABO blood groups?

Accepted Answer

Alleles $$I^A$$ and $$I^B$$ are both expressed in individuals with genotype $$I^A I^B.$$

Question 13

Which scenario illustrates polygenic inheritance?

Accepted Answer

Human skin color, which is influenced by several genes.

Question 14

What is the heterozygote advantage in sickle-cell disease?

Accepted Answer

Heterozygotes have resistance to malaria and usually do not suffer severe sickle-cell symptoms.

Question 15

Which equation represents the probability of an offspring being albino if both parents are carriers ($$Aa 	imes Aa$$)?

Accepted Answer

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

Question 16

Which of the following best describes epistasis?

Accepted Answer

One gene masks or alters the expression of another gene.

Question 17

A couple, both carriers for cystic fibrosis ($$Cc$$), have a child. What is the probability that the child will be a carrier?

Accepted Answer

$$\frac{1}{2}$$

Question 18

Which of the following is a multifactorial trait?

Accepted Answer

Heart disease, influenced by genetic, environmental, and lifestyle factors.

Question 19

If a person with genotype $$I^A i ($$blood type A) has a child with a person with genotype $$I^B i ($$blood type B), what are the possible blood types of their children?

Accepted Answer

A, B, AB, and O

Question 20

Which prenatal genetic testing method can be performed earliest in pregnancy?

Accepted Answer

Cell-free fetal DNA (cffDNA)

Mendelian Genetics and Extensions: Principles of Heredity

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