Question

choose the pair of terms that correctly completes this sentence: catabolism is to anabolism as ____ is to ____.

○ exergonic; spontaneous

○ exergonic; endergonic

○ free energy; entropy

○ work; energy

Explanation:

To solve this, we analyze the relationship between catabolism and anabolism. Catabolism breaks down molecules (releases energy, exergonic), while anabolism builds molecules (requires energy, endergonic). Now we check each option:

• "exergonic; spontaneous": Exergonic reactions are spontaneous, but this doesn't mirror catabolism - anabolism (which is a breakdown - build - up, energy - release - energy - require relationship).
• "exergonic; endergonic": Exergonic reactions release energy (like catabolism, which breaks down and releases energy), and endergonic reactions absorb energy (like anabolism, which builds up and requires energy). This matches the catabolism - anabolism relationship.
• "free energy; entropy": Free energy and entropy are different thermodynamic concepts, not related like catabolism - anabolism.
• "work; energy": Work is a form of energy transfer, not a complementary process like catabolism - anabolism.

Answer:

B. exergonic; endergonic