Cellular Respiration Overview

Cellular Respiration Overview

• Cellular respiration is a series of catabolic reactions that break down glucose to produce ATP (adenosine triphosphate).
• ATP serves as the primary energy currency of cells, transporting energy to power vital reactions.
• Glucose is oxidized to form carbon dioxide, while oxygen is reduced to form water.
• This process releases usable energy in the form of ATP.

Energy Pathways

• Cellular respiration involves two main pathways: aerobic and anaerobic.
• Aerobic respiration requires oxygen to function, while anaerobic respiration does not.

Aerobic Respiration Stages

• Aerobic respiration has three stages: Glycolysis, Krebs Cycle, and Electron Transport Chain (ETC).
• Glycolysis: Glucose is broken down into pyruvate in the cytosol, producing 2 ATP molecules. Pyruvate is then transferred to the mitochondria.
• Krebs Cycle (Citric Acid Cycle): Pyruvate enters the mitochondria and is further oxidized, producing 2 ATP molecules, carbon dioxide, NADH, FADH2, and high-energy electrons.
• Electron Transport Chain (ETC): High-energy electrons from NADH and FADH2 are passed along a chain, culminating in the synthesis of 34 ATP molecules with oxygen and hydrogen.

Anaerobic Respiration Stages

• Anaerobic respiration has two stages: Glycolysis and Fermentation.
• Glycolysis: Glucose is broken down into pyruvate, producing 2 ATP molecules.
• Fermentation: Pyruvate is further processed in the absence of oxygen to regenerate NAD+ for glycolysis. This results in only 2 ATP molecules.

Types of Fermentation

• Lactic Acid Fermentation: Occurs in animals and some bacteria, producing lactic acid and regenerating NAD+.
• Alcohol Fermentation: Occurs in microorganisms like yeast, producing ethanol and regenerating NAD+.