Which of the following is a necessary trait for a molecule to function as genetic material?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → All of these
A molecule can act as genetic material only if it meets four criteria. It must make copies of itself (replication), be chemically and structurally stable, allow slow changes (mutation) for evolution, and express itself as Mendelian characters. DNA and RNA both meet the first criterion, while proteins fail it.
Option (1) It should be capable of expressing itself in the form of 'Mendelian characters.' — Correct statement, but it is only one of the correct points, so on its own it is not the answer. The genetic material must express itself in the form of Mendelian characters, that is, as traits the organism shows.
Option (2) It should be able to replicate itself. — Correct statement, but it is only one of the correct points, so on its own it is not the answer. The genetic material must be able to generate its replica. Base pairing and complementarity let both DNA and RNA direct their own copying.
Option (3) It should allow for slow changes necessary for evolution. — Correct statement, but it is only one of the correct points, so on its own it is not the answer. The genetic material must give scope for slow changes (mutation), because evolution needs such changes.
NCERT Extract:
Properties of Genetic Material (DNA versus RNA) – “… A molecule that can act as a genetic material must fulfill the following criteria:
(i) It should be able to generate its replica (Replication).
(ii) It should be stable chemically and structurally.
(iii) It should provide the scope for slow changes (mutation) that are required for evolution.
(iv) It should be able to express itself in the form of ‘Mendelian Characters’.”