Question 1

Which of the following best describes the main structural difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are circular and lack histones, while eukaryotic chromosomes are linear and complexed with histone proteins.

Question 2

A human muscle cell contains 46 chromosomes. What is the ploidy level and chromosome number of a human egg cell?

Accepted Answer

Haploid, 1n = 23

Question 3

Which of the following events marks the transition from prophase to prometaphase during mitosis?

Accepted Answer

The nuclear envelope breaks down, allowing spindle microtubules to access chromosomes.

Question 4

Which protein complex is responsible for holding sister chromatids together until anaphase?

Accepted Answer

Cohesin

Question 5

During the G1-to-S phase transition, which protein must be phosphorylated by Cyclin-CDK complexes to release E2F and initiate DNA replication?

Accepted Answer

Retinoblastoma protein (Rb)

Question 6

Which of the following is a function of Cyclin-Dependent Kinase Inhibitors (CDKIs) such as p16, p21, and p27?

Accepted Answer

They halt cell cycle progression by inhibiting Cyclin-CDK complexes.

Question 7

Which of the following best describes a homologous pair of chromosomes?

Accepted Answer

They are chromosomes that carry the same genes but may have different alleles, one from each parent.

Question 8

Which checkpoint in the cell cycle ensures that all chromosomes are properly aligned before separation?

Accepted Answer

Spindle (Metaphase) checkpoint

Question 9

A diploid cell (2n = 4) undergoes mitosis. How many daughter cells are produced, and what is their ploidy?

Accepted Answer

Two daughter cells, each diploid

Question 10

Which of the following statements about binary fission in bacteria is correct?

Accepted Answer

It produces two genetically identical daughter cells through asexual reproduction.

Question 11

Which of the following best describes the role of histones in eukaryotic chromosomes?

Accepted Answer

They help condense and organize DNA into chromatin.

Question 12

If a cell is described as 4n = 16, how many sets of chromosomes does it have, and what is the total number of chromosomes?

Accepted Answer

Four sets, 16 chromosomes

Question 13

Which of the following is true regarding the difference between autosomes and sex chromosomes in humans?

Accepted Answer

There are 22 pairs of autosomes and 1 pair of sex chromosomes in humans.

Question 14

Which of the following best explains why loss of cell cycle control can lead to cancer?

Accepted Answer

Proto-oncogenes mutate into oncogenes, leading to uncontrolled cell division.

Question 15

Which phase of the cell cycle is characterized by active gene expression and preparation for DNA synthesis?

Accepted Answer

G1 phase

Question 16

Which of the following is a correct description of a karyotype?

Accepted Answer

A visual representation of the complete set of chromosomes in a cell, arranged by size and shape.

Question 17

Which of the following best describes the function of the centromere?

Accepted Answer

It is the region where sister chromatids are attached and where kinetochores form.

Question 18

Which of the following is true about the products of mitosis in a diploid organism?

Accepted Answer

The daughter cells are genetically identical to each other and to the parent cell.

Question 19

Which of the following is a real-world example of the importance of mitosis?

Accepted Answer

Regeneration of skin cells after a cut or injury.

Chromosomal Basis of Heredity: Cell Division, Chromosome Structure, and Cell Cycle

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