Cellular Respiration and Energy Production Quiz

Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP, the energy molecule used by the body. The process of cellular respiration can be divided into three main stages: glycolysis, the Krebs cycle, and the electron transport chain.

1. Glycolysis: This is the initial breakdown of glucose into pyruvate, which occurs in the cytoplasm of the cell. Glycolysis produces a molecule of ATP and two molecules of NADH, which are used in the electron transport chain.

2. Krebs Cycle (also known as the Citric Acid Cycle): This process takes place in the mitochondrial matrix and requires oxygen. The Krebs cycle uses the pyruvate molecules from glycolysis to generate 2 ATP and several molecules of FADH2. The cycle consists of nine enzyme-catalyzed reactions that can be divided into three stages:

• Acetyl CoA binds a four- carbon molecule (oxaloacetate) producing a six- carbon molecule (citrate).
• Two carbons are removed as carbon dioxide.
• The four- carbon starting material is regenerated.

3. Electron Transport Chain (ETC): The ETC uses the NADH and FADH2 molecules formed during glycolysis and the Krebs cycle to generate a proton gradient. This gradient ultimately leads to the production of ATP. The ETC takes place in the mitochondrial matrix and requires oxygen.

4. Anaerobic Respiration: In the anaerobic conditions, the body uses a different pathway for energy production, called anaerobic respiration. This process does not require oxygen and produces ATP through a different pathway.

5. Energy production: The energy produced during cellular respiration is used to support many other reactions in the body. ATP is particularly important for energetically unfavorable reactions that would otherwise not occur.

Cellular respiration takes place in the cytoplasm and mitochondria of each cell of the body. Glycolysis occurs inside the cytoplasm, while the Krebs cycle and the electron transport chain occur in the mitochondria. The process of cellular respiration is a series of chemical reactions that break down glucose and other organic fuel molecules from carbohydrates, fats, and proteins, and diverting the chemical energy in these molecules into ATP