Question 1

Which of the following best describes incomplete dominance in a Mendelian monohybrid cross?

Accepted Answer

The heterozygote expresses a phenotype that is intermediate between the two homozygotes.

Question 2

A woman who is a carrier for an X-linked recessive disorder and a man who is unaffected have a son. What is the probability that their son will be affected by the disorder?

Accepted Answer

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

Question 3

Which term describes the phenomenon where one gene influences multiple, seemingly unrelated phenotypic traits?

Accepted Answer

Pleiotropy

Question 4

In a dihybrid cross involving two independently assorting genes, what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 5

Which of the following best explains the difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are typically circular and lack histones, while eukaryotic chromosomes are linear and associated with histones.

Question 6

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 7

Which equation is used to calculate the expected number of recombinants in a genetic cross using the binomial theorem?

Accepted Answer

$$P(k) = \binom{n}{k} p^k (1-p$$)^{n-k}$$

Question 8

A geneticist observes that a certain trait is only passed from mothers to all of their children, regardless of the children's sex. Which inheritance pattern does this suggest?

Accepted Answer

Mitochondrial inheritance

Question 9

Which of the following best describes the role of the SRY gene in human development?

Accepted Answer

It initiates male sex determination by triggering testis development.

Question 10

If two genes are linked and the recombination frequency between them is 20%, what is the map distance between the genes?

Accepted Answer

$$20$$ centimorgans (cM)

Question 11

Which process occurs during Prophase I of meiosis and increases genetic diversity?

Accepted Answer

Crossing over (chiasmata formation)

Question 12

A test cross is performed between a dihybrid plant (AaBb) and a double recessive plant (aabb). If the genes are unlinked, what is the expected ratio of offspring phenotypes?

Accepted Answer

$$1:1:1:1$$

Question 13

Which term refers to the phenomenon where the expression of one gene is affected by another gene at a different locus?

Accepted Answer

Epistasis

Question 14

A woman with genotype $$X^DX^d ($$where $$D is $$dominant and $$d is $$recessive) for an X-linked trait marries a man with genotype $$X^dY. $$What is the probability that their daughter will express the dominant phenotype?

Accepted Answer

$$\frac{3}{4}$$

Question 15

Which of the following best describes the function of centromeres during cell division?

Accepted Answer

They serve as attachment points for spindle fibers, ensuring proper chromosome segregation.

Question 16

Which equation is used to calculate the chi-square ($$\$$chi^2$$) statistic for goodness of fit in genetics?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O - E)^2$}{E}$$

Question 17

Which of the following is a consequence of nondisjunction during meiosis?

Accepted Answer

Aneuploidy, such as trisomy 21 (Down syndrome)

Question 18

Which term describes the observable physical or biochemical characteristics of an organism as determined by both genetic makeup and environmental influences?

Accepted Answer

Phenotype

Question 19

Which scientist is credited with discovering the basic principles of heredity through experiments with pea plants?

Accepted Answer

Gregor Mendel

Question 20

A geneticist observes variable expressivity in a population. What does this mean?

Accepted Answer

Individuals with the same genotype show differences in the degree or manner of expression of a trait.

Genetics Study Guide: Key Concepts, Crosses, and Chromosomal Inheritance

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