Which of the following statements is not true for cancer cells in relation to mutations ?
- Mutations inhibit production of telomerase
- Mutations in proto-oncogenes accelerate the cell cycle
- Mutations destroy telomerase inhibitor
- Mutations inactivate the cell control
Answer
(1) Mutations inhibit production of telomerase
Solution
Cancer cells divide indefinitely, and for this they must keep their telomeres long.
So mutations in cancer cells activate (not inhibit) telomerase, e.g. by destroying the telomerase inhibitor, which is why (3) is true.
Mutations also convert proto-oncogenes into oncogenes, which accelerate the cell cycle, so (2) is true; and they inactivate the normal cell-cycle control (contact inhibition, tumour suppressors), so (4) is true.
∴ "Mutations inhibit production of telomerase" is not true.
Answer: (1)