DNA and cells - CANCER Flashcards
What is a carcinogen?
A cancer inducing agent
What is apoptosis?
Programmed cell death (when the cell has irreparable damage it self destructs)
What is a mutation?
A change in the DNA sequence
What is a tumour?
Abnormal growth of tissue
What is cancer?
- When cells in a specific part of the body grow and reproduce uncontrollably
- The cancerous cells can invade and destroy surrounding healthy tissue, including organs
What is metastasis?
The process when tumour cells invade other tissues, forming secondary cancers throughout the body
Name 3 examples of carcinogens
- Tar (in tobacco)
- UV light
- Asbestos
What are oncogenes?
Mutated genes that form due to carcinogens, that has potential to cause cancer
What are benign tumours?
- Non cancerous
- Contain abnormal cells surrounded by a connective tissue capsule
What is a malignant tumour?
- Cancerous
- Contains a clump of cancer cells
What is p53?
A significant tumour suppression gene
What does p53 do?
- Detects damaged DNA
- Inhibits progression to S phase
- Activates DNA repair enzymes
- If DNA cannot be repaired, apoptosis is triggered
What happens if the p53 gene mutates?
- Cell cycle continues
- Cells can become cancerous
How do mutations lead to cancer?
The mutations accumulate - leading to more abnormal growth and metastasis
How do we treat cancer?
By blocking some part of the cell cycle
What happens if we disrupt the cell cycle?
Cell division (and therefore cancer growth) stops
How do drugs used to treat cancer disrupt the cell cycle?
- Prevent DNA from replicating
- Interfere with spindle formation; therefore inhibiting metaphase
Why are cancer cells more greatly affected by these drugs than normal cells?
Cancer cells have a very rapid rate of cell division; hence cancer cells are damaged to a greater extent than normal cells
Give two differences between the effect of drugs on cancer cells compared with healthy cells throughout the treatment (PPQ)
- Healthy cell number recovers (increases) much quicker
- Cancer cell numbers don’t increase as much
Why do chemotherapy drugs have to be given a number of times if they are to be effective in treating cancer?
Cancer cell numbers increase after each dose is complete, so treatment needs to occur again
Mikanolide is a drug that inhibits the enzyme DNA polymerase. Explain why this drug may be effective against some types of cancer (PPQ)
- Mikanolide slows DNA replication
- A new strand of DNA is not formed
If the DNA of the cell is damaged, a protein called p53 stops the cell cycle. Mutation in the gene for p53 could cause cancer to develop. Explain how (PPQ)
- The cell with faulty DNA continues to divide
- Uncontrolled division produces cancer
