A) How many electrons must move down the Electron Transport Chain before energy is made? (1 point)
5
3
4
2
2
To determine the number of electrons that must move down the Electron Transport Chain (ETC) before energy is synthesized, we need to understand the process of oxidative phosphorylation.
During oxidative phosphorylation, electrons are transferred through a series of protein complexes in the ETC. As the electrons flow through the ETC, energy is released and used to pump protons across the mitochondrial inner membrane, creating an electrochemical gradient. This gradient is then used by ATP synthase to generate ATP.
In this process, each pair of electrons transferred from NADH (nicotinamide adenine dinucleotide) to oxygen results in the synthesis of 3 molecules of ATP. Similarly, each pair of electrons transferred from FADH2 (flavin adenine dinucleotide) to oxygen results in the synthesis of 2 molecules of ATP.
Since the question does not specify whether the electrons come from NADH or FADH2, we can assume that either can be involved. However, it's important to note that the majority of electrons in oxidative phosphorylation come from NADH.
So, if we consider that each pair of electrons contributes to the synthesis of ATP, we can conclude that:
- NADH: 1 pair of electrons = 3 ATP
- FADH2: 1 pair of electrons = 2 ATP
Therefore, the number of electrons needed before energy is made depends on whether the source is NADH or FADH2. If the source is NADH, 5 electrons are required (5 pairs of electrons * 3 ATP per pair). If the source is FADH2, 4 electrons are needed (2 ATP per pair * 2 pairs of electrons). So, the answer would be:
A) 5 electrons