BIOLOGY - RESPIRATION QUICK NOTES

Glycolysis takes place in the cytoplasm:

Glucose is activated by 2ATP - substrate-level phosphorylation

→ splits into two molecules of TP
TP is oxidised to form pyruvate, producing ATP and reduced NAD.

Link reaction:

pyruvate is oxidised, → NADH produced
loses a molecule of CO2
combines with coenzyme A to produce Acetyl coenzyme A

Krebs cycle: (matrix)

acetyl coA + 4-C molecule becomes a 6-C molecule
the 6-C molecule loses 2 molecules of CO2, produces reduced coenzymes FAD and NAD and produces one molecule of ATP
this regenerates the 4-C molecule, which accepts another molecule of acetyl coA

Electron-transport chain:

FAD and NAD donate electrons to first molecule in electron transport chain
Protons released in matrix
Protons are actively transported across membrane using energy from electron-transfer
H+ ions move passively down their electrochemical concentration gradient through ATP synthetase, producing ATP via oxidative phosphorylation.
Oxygen accepts H+ ions and electrons, forming water (is final electron acceptor)

Cyanide:

non-competitive inhibitor of final enzyme in electron transport chain
oxygen cannot accept electrons
electron transport chain stops – build of of H+ ions, reduced NAD and FAD
no ATP can be produced
cell dies

Anaerobic respiration:

Glycolysis followed by:

production of ethanol +CO2 + NAD from pyruvate + NADH – plants/yeast
production of lactate and NAD from NADH – animals

Lactate build up lowers pH, causing enzymes to work more slowly. This slows respiration (both anaerobic and aerobic), concequently causing muscle cramp and fatigue.

	Created by Emily B over 10 years ago

A-level Biology Note on Biology - Respiration Notes, created by Emily B on 24/11/2013.