Glycolysis and Respiration Overview

Glycolysis Overview

• Glycolysis is a metabolic pathway, fundamental to both aerobic and anaerobic respiration
• It breaks down glucose into pyruvate, functioning with or without oxygen
• This process occurs within the cytoplasm of a cell

Aerobic Respiration vs. Anaerobic Respiration

• A key distinction lies in the fate of pyruvate
• In aerobic respiration, pyruvate proceeds through the Krebs cycle and electron transport chain, yielding significantly more ATP
• In anaerobic respiration, pyruvate is converted into products like lactate, resulting in a lower ATP yield

Glycolysis Details

• Glucose is broken down into two molecules of pyruvate within the cytoplasm
• Two ATP and NADH molecules are released during this conversion
• This glucose-to-pyruvate conversion is an oxidation reaction, as glucose loses electrons
• The released electrons combine with NAD+ to form NADH (reduction reaction)

ATP Production

• Glycolysis initially uses two ATP molecules to activate glucose
• It generates four ATP molecules, resulting in a net gain of two ATP molecules per glucose molecule
• This ATP production occurs via substrate-level phosphorylation, where a phosphate group is directly moved from a high-energy molecule to ADP

Further Cellular Processes

• The two NADH molecules produced during glycolysis are byproducts
• NADH is then transported to the mitochondria
• Within the mitochondria, NADH is oxidized, regenerating NAD+ and powering further cellular processes, particularly the citric acid cycle and electron transport chain. These pathways create significantly more ATP.