Q: In a population, the frequency of allele $$A is$$ $$0.7$$ and allele $$a is$$ $$0.3. $$What is the expected frequency of heterozygotes ($$Aa) $$under Hardy-Weinberg equilibrium?

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Question 1

Which of the following best describes Mendel's law of independent assortment?

Accepted Answer

Alleles of different genes assort independently of one another during gamete formation.

Question 2

A monohybrid cross between two heterozygous pea plants ($$Aa 	imes Aa) $$produces offspring. What is the expected genotypic ratio?

Accepted Answer

$$1:2:1 (AA$$:Aa:aa)

Question 3

In a dihybrid cross ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio if both traits exhibit complete dominance and assort independently?

Accepted Answer

$$9:3:3:1$$

Question 4

A pedigree shows a trait appearing in every generation and affecting both males and females equally. Which inheritance pattern is most likely?

Accepted Answer

Autosomal dominant

Question 5

Which equation represents the Hardy-Weinberg equilibrium for a gene with two alleles, $$A$$ and $$a$$, with frequencies $$p$$ and $$q$$?

Accepted Answer

$$p^2 + 2pq$$ + $$q^2 = 1$

Question 6

A population has 36 individuals with genotype $$AA$$, 48 with $$Aa$$, and 16 with $$aa. $$What is the frequency of allele $$A$$?

Accepted Answer

$$0.6$$

Question 7

Which of the following is an example of codominance?

Accepted Answer

AB blood type in humans, where both A and B antigens are expressed

Question 8

In a cross between two heterozygotes for a lethal allele ($$L$$), what is the expected ratio of surviving offspring?

Accepted Answer

$$2:1 ($$heterozygous:homozygous normal)

Question 9

Which statistical test is used to determine if observed genetic ratios differ significantly from expected ratios?

Accepted Answer

Chi-square test

Question 10

A trait is expressed only in males, even though both sexes carry the gene. What is this pattern called?

Accepted Answer

Sex-limited inheritance

Question 11

Which of the following is NOT an assumption of the Hardy-Weinberg equilibrium?

Accepted Answer

Natural selection is acting on the population

Question 12

Which mechanism is used by mammals for dosage compensation?

Accepted Answer

X-chromosome inactivation

Question 13

Which of the following best describes eugenics?

Accepted Answer

A philosophy advocating selective breeding to improve genetic traits in humans

Question 14

Which of the following is a consequence of having only one X chromosome (Turner syndrome) in humans?

Accepted Answer

Individuals are female with characteristic physical features and infertility

Question 15

In a population, the frequency of allele $$A is$$ $$0.7$$ and allele $$a is$$ $$0.3. $$What is the expected frequency of heterozygotes ($$Aa) $$under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 16

Which of the following best explains why sex chromosomes are distinguished from autosomes?

Accepted Answer

Sex chromosomes determine the sex of an organism and carry genes with unique inheritance patterns

Question 17

A cross between two plants produces offspring with a 9:7 ratio. Which gene interaction is most likely responsible?

Accepted Answer

Complementary gene interaction

Question 18

Which of the following forces does NOT increase genetic variation in a population?

Accepted Answer

Genetic drift

Question 19

A man with an X-linked recessive disorder marries a woman who is a carrier. What is the probability that their daughter will have the disorder?

Accepted Answer

$$0.5$$

Question 20

Which environmental factor can determine sex in some reptiles?

Accepted Answer

Incubation temperature of eggs

Genetics Exam 1 Review: Mendelian Genetics, Allele Interactions, Population Genetics, Sex Determination, and Eugenics

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