Cellular Respiration

Aerobic respiration is highly efficient because it utilizes oxygen as a final electron acceptor, allowing for the complete oxidation of glucose into CO2 and water, yielding significantly more ATP than fermentation pathways.

While the theoretical maximum yield of aerobic respiration is often cited as 36-38 ATP per glucose molecule, 38 is the standard textbook value for the total yield.

Lactic acid fermentation is the process used by bacteria to convert lactose in milk into lactic acid, which causes the milk to thicken and become yogurt.

Both prokaryotes and eukaryotes have the metabolic machinery to perform fermentation when oxygen is unavailable.

Aerobic sports require sustained oxygen delivery to working muscles, which strengthens the heart and improves cardiovascular conditioning. Anaerobic sports also exercise the heart, but aerobic activities provide more continuous cardiovascular stress. Option A is incorrect because anaerobic sports do exercise the heart.

Glycolysis is an anaerobic process that occurs in the cytosol and does not require oxygen to break down glucose into pyruvate.

The electron transport chain (oxidative phosphorylation) produces the vast majority of ATP during cellular respiration through the action of ATP synthase.

Acetyl-CoA is the substrate that enters the Krebs Cycle (also known as the citric acid cycle) to be oxidized.

The first process of cellular respiration is glycolysis, which is anaerobic and does not require oxygen.

In glycolysis, a single 6-carbon glucose molecule is split into two 3-carbon pyruvate molecules.

Yeast fermentation (alcoholic fermentation) converts pyruvate into ethanol and carbon dioxide while regenerating NAD+.

During glycolysis, one molecule of glucose is broken down into two molecules of pyruvate. Concurrently, energy is captured to produce ATP and NADH.

Oxygen acts as the final electron acceptor at the end of the electron transport chain, where it combines with electrons and protons to form water.

Glycolysis takes place in the cytosol (cytoplasm) of the cell, outside of the mitochondria.

Cellular respiration is the metabolic process that breaks down glucose (in the presence of oxygen) into carbon dioxide, water, and ATP.