Which of the following statements is not true for cancer cells in relation to mutations?
Answer: (D) Mutations inhibit production of telomerase. Answer: (D) Mutations inhibit production of telomerase Solution: The question asks which statement is NOT true.
- A.Mutations in proto-oncogenes accelerate the cell cycle
- B.Mutations destroy telomerase inhibitor
- C.Mutations inactivate the cell control
- D.Mutations inhibit production of telomerase✓
Correct Answer
(D) Mutations inhibit production of telomerase
Solution & Explanation
Answer: (D) Mutations inhibit production of telomerase Solution: The question asks which statement is NOT true. Cancer cells become 'immortal' by reactivating/overexpressing telomerase, which keeps telomeres long and lets the cells divide endlessly; mutations therefore INCREASE (not inhibit) telomerase production. So option D is the false statement and is the correct answer. NCERT notes that in cancer cells there is a breakdown of growth-regulatory mechanisms and that proto-oncogenes, when activated, lead to oncogenic transformation. Why the others are true: mutations activating proto-oncogenes accelerate the cell cycle; loss of cell-cycle control (regulation) is a hallmark of cancer; destruction of a telomerase inhibitor would also raise telomerase activity. These are all true of cancer cells, making D the exception. NCERT Reference: NCERT Ch7, p.141, lines 8, 30-33: "proto oncogenes have been identified in normal cells which, when activated under certain conditions, could lead to oncogenic transformation"