The correct sequence of electron flow during aerobic respiration would be:
1. food → Krebs cycle → ATP → NAD⁺
2. food → NADH → electron transport chain → oxygen
3. glucose → pyruvate → ATP → oxygen
4. glucose → ATP → electron transport chain → NADH

The components of the mitochondrial electron transport chain are located:
1. in mitochondrial matrix
2. in outer mitochondrial membrane
3. in inner mitochondrial membrane
4. in intermembrane space

The correct sequence of flow of electrons downhill in the mitochondrial electron transport chain would be:
1. ubiquinone, cytochromes, FMN, Fe-S
2. cytochromes, FMN, ubiquinone, Fe-S
3. Fe-S, FMN, cytochromes, ubiquinone
4. FMN, Fe-S, ubiquinone, cytochromes

Electron is donated to the mitochondrial ETC at the lowest energy level by:

The source of oxygen for the synthesis of water in oxidative phosphorylation is:
1. carbon dioxide
2. glucose
3. molecular oxygen
4. pyruvate

When electron pass downhill in the ETC, the energy released is used to pump protons into:
1. matrix of mitochondria
2. cytosol
3. mitochondrial inner membrane
4. mitochondrial intermembrane space

ATP synthesis during oxidative phosphorylation in mitochondria is directly driven by:
1. oxidation of glucose.
2. electron transport downhill in the ETC.
3. terminal transfer of electrons to oxygen.
4. chemiosmosis.

ATP synthase is located in the mitochondrial:

Isolated inner membrane of mitochondria can carry out:
1. the citric acid cycle
2. oxidative phosphorylation
3. glycolysis and fermentation
4. reduction of ${\mathrm{NAD}}^{+}$

The number of oxygen molecules required each time a molecule of glucose is completely oxidized via aerobic respiration is: