Q: Which of the following equations correctly represents Mendel’s law of segregation for a monohybrid cross between two heterozygotes ($$Tt \times Tt) $$for tallness in pea plants?

$$Tt \times Tt \rightarrow 1\ TT : 2\ Tt : 1\ tt$$

Question 1

Which of the following best describes the role of tumor suppressor genes in the cell cycle?

Accepted Answer

They encode proteins that repair DNA damage and inhibit cell cycle progression when necessary.

Question 2

A patient is diagnosed with a mutation in the p53 gene. Which of the following outcomes is most likely?

Accepted Answer

Uncontrolled cell proliferation due to failure to arrest the cell cycle after DNA damage.

Question 3

Which of the following equations correctly represents Mendel’s law of segregation for a monohybrid cross between two heterozygotes ($$Tt 	imes Tt) $$for tallness in pea plants?

Accepted Answer

$$Tt 	imes Tt ightarrow 1\ TT : 2\ Tt : 1\ tt$$

Question 4

A woman with blood type A (genotype $$I^A i) $$and a man with blood type B (genotype $$I^B i) $$have a child. What is the probability that their child will have blood type O?

Accepted Answer

$$0.25$$

Question 5

Which of the following best explains why proto-oncogenes can become oncogenes?

Accepted Answer

A gain-of-function mutation causes proto-oncogenes to be permanently activated, leading to uncontrolled cell division.

Question 6

A geneticist is studying a dihybrid cross between two plants heterozygous for both seed color (Yy) and seed shape (Rr). According to Mendel’s law of independent assortment, what is the expected phenotypic ratio in the offspring?

Accepted Answer

$$9:3:3:1$$

Question 7

Which of the following scenarios best illustrates incomplete dominance?

Accepted Answer

A cross between a red-flowered plant and a white-flowered plant produces pink-flowered offspring.

Question 8

Which of the following best describes the function of cyclin-dependent kinases (CDKs) in the regulation of the cell cycle?

Accepted Answer

CDKs phosphorylate target proteins only when bound to cyclins, promoting cell cycle progression.

Question 9

A pedigree shows a trait that appears in every generation and affects both males and females equally. Which mode of inheritance is most likely?

Accepted Answer

Autosomal dominant

Question 10

Which of the following is a key difference between meiosis and mitosis?

Accepted Answer

Meiosis produces four genetically unique haploid cells, while mitosis produces two genetically identical diploid cells.

Question 11

A man with hemophilia (an X-linked recessive disorder) and a woman who is a carrier have a child. What is the probability that their son will have hemophilia?

Accepted Answer

$$0.5$$

Question 12

Which of the following best describes the process of crossing over during meiosis?

Accepted Answer

Exchange of genetic material between homologous chromosomes during prophase I.

Question 13

A cell is observed to have a mutation that causes the Rb protein to be nonfunctional. What is the most likely consequence?

Accepted Answer

The cell will progress through the G1/S checkpoint without proper regulation, increasing cancer risk.

Question 14

Which of the following equations correctly represents the Hardy-Weinberg equilibrium for allele frequencies $$p$$ and $$q$$?

Accepted Answer

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

Question 15

A woman who is heterozygous for a genetic disorder marries a man who is homozygous normal. If the disorder is autosomal recessive, what is the probability that their child will be affected?

Accepted Answer

$$0$$

Question 16

Which of the following best explains why cancer cells often have multiple mutations in both oncogenes and tumor suppressor genes?

Accepted Answer

Both types of mutations are required to bypass normal cell cycle controls and promote uncontrolled growth.

Question 17

A couple has a child with cystic fibrosis, an autosomal recessive disorder. Both parents are healthy. What are the genotypes of the parents?

Accepted Answer

Both are heterozygous carriers.

Question 18

Which of the following best describes the difference between a benign tumor and a malignant tumor?

Accepted Answer

Benign tumors do not invade surrounding tissues, while malignant tumors can metastasize to distant sites.

Question 19

A genetic counselor is working with a family where both parents are carriers for sickle cell anemia (an autosomal recessive disorder). What is the probability that their child will be a carrier but not affected?

Accepted Answer

$$0.5$$

Question 20

Which of the following is a real-world example of a gene-environment interaction?

Accepted Answer

Individuals with a genetic predisposition to skin cancer have a higher risk if they are exposed to excessive UV radiation.

Cell Cycle, Tumor Suppressors, Oncogenes, Meiosis, and Mendelian Genetics: Study Notes

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