Most CO₂ from catabolism is released during
a. Glycolysis.
b. The citric acid cycle.
c. Lactate fermentation.
d. Electron transport.

Verified step by step guidance

1. Understand the process of catabolism, which is the breakdown of complex molecules into simpler ones, releasing energy.
2. Identify the stages of cellular respiration: glycolysis, the citric acid cycle (also known as the Krebs cycle), and the electron transport chain.
3. Recall that glycolysis occurs in the cytoplasm and primarily breaks down glucose into pyruvate, producing a small amount of ATP and NADH, but does not release CO2.
4. Recognize that the citric acid cycle takes place in the mitochondria and involves the oxidation of acetyl-CoA, leading to the release of CO2 as a byproduct.
5. Note that lactate fermentation occurs in anaerobic conditions, converting pyruvate into lactate without releasing CO2, and the electron transport chain primarily involves the transfer of electrons to produce ATP, not CO2.

Key Concepts

Catabolism

Catabolism refers to the metabolic pathways that break down molecules into smaller units, releasing energy. It involves processes like glycolysis, the citric acid cycle, and oxidative phosphorylation, which are crucial for converting nutrients into usable energy in the form of ATP.

Citric Acid Cycle

The citric acid cycle, also known as the Krebs cycle, is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins. It is a key part of cellular respiration, where most CO2 is released as a byproduct.

Carbon Dioxide Release

Carbon dioxide release is a critical aspect of cellular respiration, occurring primarily during the citric acid cycle. As acetyl-CoA is oxidized, CO2 is produced as a waste product, which is then expelled from the cell. This process is essential for maintaining the balance of gases in the body and the environment.