9.1 Bio Content

Question 1

What are the four phases of the cell cycle?

Answer 1

G1, S, G2, and M phase.

Question 2

What are the two main functions of cell division?

Answer 2

Growth, maintenance, and repair in multicellular organisms; reproduction in single-celled organisms.

Question 3

What are the stages of mitosis?

Answer 3

Prophase, Prometaphase, Metaphase, Anaphase, and Telophase.

Question 4

What is the difference between somatic cells and gametes?

Answer 4

Somatic cells are diploid (2n) and produced by mitosis; gametes are haploid (1n) and produced by meiosis.

Question 5

What is chromatin?

Answer 5

A complex of DNA and histone proteins that make up chromosomes.

Question 6

What is a chromosome?

Answer 6

A single long double helix of DNA wrapped around histones containing genetic information.

Question 7

What happens during the S phase?

Answer 7

DNA replication occurs, producing sister chromatids.

Question 8

What happens during G1 and G2 phases?

Answer 8

G1 is cell growth and preparation for DNA replication; G2 prepares the cell for mitosis.

Question 9

What is cytokinesis?

Answer 9

Division of the cytoplasm to form two daughter cells.

Question 10

What is the M phase-promoting factor (MPF)?

Answer 10

A regulatory complex made of cyclin and Cdk that triggers mitosis.

Question 11

What are the main checkpoints in the cell cycle?

Answer 11

G1, G2, and two M-phase checkpoints.

Question 12

What happens if checkpoints fail?

Answer 12

Cells may divide uncontrollably, leading to cancer.

Question 13

What is a proto-oncogene?

Answer 13

A normal gene that promotes cell division; when mutated, it becomes an oncogene.

Question 14

What is a tumor suppressor gene?

Answer 14

A gene that prevents uncontrolled cell division; when defective, cancer can result.

Question 15

What protein regulates the G1 checkpoint?

Answer 15

The Rb protein, which controls the E2F transcription factor.

Question 16

What does the p53 protein do?

Answer 16

It detects DNA damage and can pause the cell cycle or initiate apoptosis.

Question 17

What is binary fission?

Answer 17

A process in which prokaryotes replicate and divide without mitosis.

Question 18

What happens during anaphase?

Answer 18

Sister chromatids separate and move to opposite poles.

Question 19

What happens during metaphase?

Answer 19

Chromosomes align at the metaphase plate.

Question 20

What happens during telophase?

Answer 20

Nuclear envelopes reform and chromosomes decondense.