Question 1

Which of the following best describes the role of cyclins in the regulation of the cell cycle?

Accepted Answer

Cyclins activate cyclin-dependent kinases (CDKs), which phosphorylate target proteins to progress the cell cycle.

Question 2

During which phase of the cell cycle does DNA exist primarily as chromatin, and what is the significance of this structure?

Accepted Answer

During interphase; chromatin's loose structure permits access for DNA replication and transcription.

Question 3

A researcher observes a tissue sample and calculates a mitotic index of $$ \frac{8}{100} = 0.08 . $$What does this value indicate about the tissue?

Accepted Answer

8% of the cells are undergoing mitosis, suggesting a moderate rate of cell division.

Question 4

Which of the following best explains the difference between plant and animal cell cytokinesis?

Accepted Answer

Plant cells build a new cell wall from vesicles at the center, while animal cells constrict the membrane using a contractile ring.

Question 5

A mutation in the gene encoding the protein cohesin would most likely result in which of the following during mitosis?

Accepted Answer

Premature separation of sister chromatids, leading to aneuploidy.

Question 6

Which of the following is an example of unequal cytokinesis, and what is its biological significance?

Accepted Answer

Formation of polar bodies during oogenesis; allows most cytoplasm to be retained in one egg cell.

Question 7

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

Accepted Answer

Exchange of genetic material between homologous chromosomes during prophase I, resulting in new allele combinations.

Question 8

A patient is diagnosed with Down syndrome, which is caused by nondisjunction. Which meiotic event most likely led to this condition?

Accepted Answer

Failure of homologous chromosomes to separate during meiosis I, resulting in a gamete with two copies of chromosome 21.

Question 9

Which of the following mechanisms does NOT contribute to genetic variation in gametes?

Accepted Answer

Replication of DNA during S phase of interphase.

Question 10

Which of the following best distinguishes between spermatogenesis and oogenesis in humans?

Accepted Answer

Oogenesis produces one large ovum and polar bodies, while spermatogenesis produces four functional sperm.

Question 11

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

Accepted Answer

Autosomal dominant

Question 12

Which of the following genotypes would result in a person with blood type AB, given the inheritance pattern of the ABO blood group?

Accepted Answer

$$ I^A I^B $$

Question 13

A woman who is a carrier for hemophilia (an X-linked recessive disorder) and a man who does not have hemophilia have a son. What is the probability that their son will have hemophilia?

Accepted Answer

$$ 50 \% $$

Question 14

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

Accepted Answer

They inhibit cell division or trigger apoptosis when DNA damage is detected.

Question 15

Which of the following is the correct sequence of events in meiosis I?

Accepted Answer

Prophase I, Metaphase I, Anaphase I, Telophase I

Question 16

Which of the following best defines a bivalent during meiosis?

Accepted Answer

A structure formed by two homologous chromosomes, each consisting of two sister chromatids, during prophase I.

Question 17

Which of the following is a likely consequence if the kinetochore fails to attach to spindle microtubules during mitosis?

Accepted Answer

Sister chromatids may not separate properly, leading to aneuploidy.

Question 18

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Sister chromatids are identical copies formed by DNA replication; homologous chromosomes are similar but not identical, one from each parent.

Question 19

Which of the following best explains why a single nucleotide polymorphism (SNP) can result in a new allele?

Accepted Answer

SNPs can alter the DNA sequence of a gene, potentially changing the encoded protein.

Question 20

A couple, both heterozygous for the autosomal recessive disease phenylketonuria (PKU), have a child. What is the probability that their child will have PKU?

Accepted Answer

$$ 25 \% $$

Cell Cycle, Meiosis, and Genetic Inheritance: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards