Question

4 multiple choice 10 points
in the electron transport chain reactions, when do the electrons have the highest potential energy?
as they combine with oxygen to form water.
as they enter the third embedded protein complex
as they leave nadh (or fadh).
5 fill in the blank 10 points
which of the following represents a decrease in potential energy?
nad+→nadh c. glucose→pyruvate
adp→atp d. oxaloacetate→citrate
the answer is type your answer...

Explanation:

• For question 4: In the electron - transport chain, electrons have the highest potential energy when they leave NADH (or FADH). As they move through the chain, they release energy. When they combine with oxygen (forming water), they have lost a large amount of energy. And when they enter the third protein complex, they have already released some energy from their initial state (leaving NADH or FADH).
• For question 5:
• In the reaction \(NAD^{+}\to NADH\), energy is consumed (reduction reaction that stores energy in the form of \(NADH\)).
• In \(ADP\to ATP\), energy is stored (phosphorylation reaction).
• In \(oxaloacetate\to citrate\), energy is stored (a reaction in the citric acid cycle that consumes energy in the form of acetyl - CoA).
• In \(glucose\to pyruvate\) (glycolysis), glucose is broken down, and some of its potential energy is released.

Answer:

1. As they leave NADH (or FADH).
2. c. glucose → pyruvate