Respiration (A-Level)

From Wikiversity

Respiration is the process by which organic molecules are broken down, releasing energy to synthesise ATP.

There are four stages:

1. Glycolysis
2. The link reaction
3. The Krebs cycle
4. The electron transport chain

Contents 1 Glycolysis 2 The link reaction 3 The Krebs cycle 4 The electron transport chain

[edit] Glycolysis

• 2 molecules of ATP are used to convert a molecule of glucose into 2 molecules of triose phosphate (TP).

glucose + 2 ATP → 2 triose phosphate + 2 ADP

• The 2 molecules of TP are then converted to 2 molecules of pyruvate

This process produces 4 molecules of ATP from 4 molecules of ADP

2 NAD coenzymes are reduced (into 2 reduced NAD coenzymes)

2 triose phosphate + 4 ADP + 2 NAD → 2 pyruvate + 4 ATP + 2 reduced NAD

[edit] The link reaction

• pyruvate + coenzyme A + NAD → acetylcoenzyme A + CO₂ + reduced NAD

[edit] The Krebs cycle

1. 4-carbon compound + acetylcoenzyme → 6-carbon compound

[edit] The electron transport chain