Question

Which of the following statements describes a common characteristic of catabolic pathways?

Answer 1

Answer:

C. They are exergonic and provide energy that can be used to produce ATP form ADP and Pi.

Explanation:

There are 2 types of metabolic reactions.

1. Anabolic reactions (Anabolism)
2. Catabolic reactions (Catabolism)

CATABOLIC REACTIONS:

They consist of reactions in which larger molecules are broken down into simpler ones. They are exergonic i.e. energy producing reactions. The released energy can be stored in the form of ATP (energy currency of cell).

ANABOLIC REACTIONS:

They consist of reactions in which larger molecules are synthesized from simpler ones. They are endergonic reactions i.e. energy is absorbed.

MEMORY AID:

An easy way to remember catabolic reactions is to think of them as "catastrophic reactions" i.e. larger molecules are destructed to produce simpler ones.

Coming back to the question,

a. They require energy from ATP hydrolysis to break down polymers into monomers.

Energy requiring reactions are anabolic and so this is the incorrect answer.

b. They are endergonic and release energy that can be used for cellular work.

Endergonic reactions are anabolic and hence this is the incorrect answer.

c. They are exergonic and provide energy that can be used to produce ATP from ADP and Pi

This statement correctly fits the definition of Catabolic reactions and is therefore the correct answer.

d. They combine small molecules into larger, more energy-rich molecules.

This statement describes anabolic reactions and hence the incorrect choice.