From Normal Division to Cancer
Part of Cancer and Cell Division Control — GCSE Biology
This deep dive covers From Normal Division to Cancer within Cancer and Cell Division Control for GCSE Biology. Cancer development, cell cycle control mechanisms, tumor formation, risk factors, prevention methods, and treatment approaches It is section 2 of 18 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 18
Practice
18 questions
Recall
22 flashcards
From Normal Division to Cancer
Normal Cell Division Control
Remember from topic-4 (Mitosis) that healthy cells have strict controls:
- Cell cycle checkpoints: Quality control points that check for DNA damage before allowing the cell to divide
- Contact inhibition: Cells stop dividing when they touch neighbouring cells
- Tumour suppressor genes: Genes that slow down cell division or cause damaged cells to be destroyed
- Growth signals: Cells normally only divide when they receive chemical signals telling them to
How Cancer Develops
Cancer is essentially a disease of cell cycle control. It develops through a multi-step process:
- Initial mutation: DNA damage occurs in genes controlling cell division
- Checkpoint failure: Cell cycle checkpoints fail to detect or respond to damage
- Uncontrolled division: Cells divide continuously without normal restrictions
- Tumor formation: Mass of abnormal cells grows larger
- Invasion and metastasis: Cancer cells spread to other parts of the body
Types of Cancer-Related Genes
- Oncogenes: Mutated genes that promote cell division (accelerator stuck on)
- Tumor suppressor genes: Mutated genes that normally prevent cancer (brakes don't work)
- DNA repair genes: Mutated genes that normally fix DNA damage
Quick Check: What is the difference between an oncogene and a tumour suppressor gene?
An oncogene is a mutated proto-oncogene that constantly stimulates cell division (like a stuck accelerator). A tumour suppressor gene normally stops division, but when mutated it no longer functions — so division is unchecked (like failed brakes). Cancer typically requires both types of gene to be affected.