Question

Electrons taking part in electron transport system inside mitochondria come from
A. Pyruvate
B. NADH ($H^+$)
C. $FADH_2$
D. Both B and C

Answer 1

Mitochondria constitute membrane-bound cell organelles that produce much of the chemical energy required to induce the cell's biochemical reactions. Chemical energy generated by mitochondria is contained in a small molecule called adenosine triphosphate ( ATP).

Complete Answer:
- The electron transport chain is the last portion of aerobic respiration. It is the only element of glucose metabolism that requires ambient oxygen.
- Electron transport is a sequence of redox reactions in which electrons are easily transported from one portion to the next, to the terminal of the chain, where electrons remove molecular oxygen and create water.
- Electron transport chain is a sequence of proteins and organic molecules located in the inner mitochondrial membrane. The electron transport system, situated in the inner mitochondrial membrane, converts electrons contributed by the reduced electron carriers NADH and $FADH_2$ to oxygen via a sequence of electron acceptors.
- And we will see, the passage of electrons through the electron transport mechanism complexes basically 'loads' a battery that is used to create ATP in oxidative phosphorylation.
- In this way, the oxidation of sugars and fatty acids is combined with the synthesis of ATP, which essentially removes energy from carbohydrates.
- $FADH_2$ is less effective in transferring electrons since the electrons are at a low energy level and thus can not easily pass their electrons.
- Instead, it moves them into a complex system that does not pump protons into the membrane.

Note: Electrons are the subatomic particles which orbit the nucleus of an atom. They are usually negatively charged and are much smaller than the nucleus of the atom.