Multiple choice

Identify the respect in which these two items are similar. The relation between an enzyme and its substrate is like the relationship between a lock and a key. Just as each key acts only upon a specific lock, so each enzyme acts only upon a specific substrate. Thus, no enzyme is an all-purpose tool.

  1. An enzyme acts only upon a specific substrate and it is not an all-purpose tool.

  2. A key acts only upon a specific lock and it is not an all-purpose tool.

  3. An enzyme acts only upon a specific substrate and it is a key.

  4. A key acts only upon a specific lock and it is an all-purpose tool.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Choice (2) is the fundamental example. Choice (1) is correct but the phrase “an enzyme is not an all-purpose tool” is a conclusion of the argument based on the similarity (or specificity of action) between an enzyme and a lock.

Keep practicing — related questions