Biology - Respiration Notes

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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.

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