Question

How many water molecules are released as byproducts in the Krebs cycle of cellular respiration?

• A. One
• B. Two
• C. Three
• D. Four

Hint:

The Krebs cycle maintains a balance between water consumption and release, ensuring efficient metabolism and energy production.

Answer 1

The Correct Option is B

Step 1: Role of water in the Krebs cycle. Water molecules are involved at two specific points in the Krebs cycle: 1. Fumarate is hydrated to malate by the enzyme fumarase, consuming one water molecule. 2. Citrate is formed from oxaloacetate and acetyl-CoA, requiring water for the reaction catalyzed by citrate synthase. Although water is consumed in the cycle, two water molecules are released as byproducts during different enzymatic reactions. 

 

Step 2: Confirm the count of water molecules released. During the step where succinyl-CoA is converted to succinate, a water molecule is indirectly associated, contributing to the net release of water in the cycle.