What You Need to Know

Key Concept Diagram

Mitosis: cell division producing two genetically identical daughter cells for growth and repair

The cell cycle: G1 growth, S DNA replication, G2 preparation, M mitosis, then cytokinesis

Cancer occurs when mutations in genes controlling the cell cycle cause uncontrolled division

Proto-oncogenes promote division; tumour suppressor genes (e.g. p53) inhibit it

Key Vocabulary

Mitosis

Cell division that produces two genetically identical daughter cells

Cell cycle

The ordered series of events a cell goes through to replicate, including growth and division

Cancer

Uncontrolled cell division caused by mutations in genes that regulate the cell cycle

Tumour suppressor gene

A gene that inhibits cell division; mutations in these can lead to cancer

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

What is the main purpose of mitosis?

To produce gametes (sex cells) for reproduction To combine genetic material from two parents To reduce chromosome number by half To produce genetically identical cells for growth and repair

Question 2

Cancer is caused by:

Mutations that cause cells to divide uncontrollably A viral infection that always spreads between people Normal cell division happening too slowly An overactive immune system destroying healthy cells

Question 3

The p53 gene is called a tumour suppressor gene because it:

Speeds up cell division Inhibits cell division and triggers repair or death of damaged cells Produces energy for dividing cells Copies DNA during replication

Cell Division and Cancer