1. ATP & Energy Transfer
Yay!

2. Energy Release Glucose is the main source of energy in a cell
Respiration releases the energy stored in the glucose
This is controlled by enzymes - involves lots of reactions
Some of the energy is converted into heat
- the rest of the energy is used for…..

3. ATP ATP is an immediate source of energy (in muscles etc.)
Made of Adenosine
– adenine + ribose
and 3 inorganic phosphates
ATP is converted into ADP + Pi to release energy
ATP can be reformed
from ADP
Glucose provides energy
for ATP regeneration

4. Role of ATP Makes energy for many processes:
E.g. muscle contraction, protein synthesis, transmission of nerve impulses
Links processes that consume energy, and release energy
2 million ATP molecules/sec used (RAPID TURNOVER)
Only 50g in the whole body
Constantly regenerated (400g/hr)

5. Oxidation / Reduction
Oxidation - the release of an electron from a substance
Substance becomes oxidised
Reduction – gain of an electron
Substance becomes reduced
Reactions often coupled together

6. Chemistry of Respiration
The release of chemical energy from food by oxidation
Stage 1 -GLYCOLYSIS (in cytoplasm)
Net gain of 2 ATP
Hydrogen (H) is released and joined to NAD (a co-enzyme)
Oxygen not needed for this stage
Occurs in the cytoplasm
(Pyruvic Acid)

7. Mitochondria Organelles in the cytoplasm Site of aerobic respiration
Cristae – membrane folds
- site of ATP production (large surface area)
More cristae = more ATP production
Central matrix – Fluid-filled (contains enzymes)
Many reactions occur in the matrix

8. Fate of pyruvic acid – aerobic respiration
Converted into acetyl CoA in the central matrix
Conversion produces 2CO2 & 2NADH2
Acetyl CoA then enters the Kreb’s/Citric Acid cycle
Net release of 6CO2 & 10NADH2
Decarboxylase enzymes control CO2 formation
CO2 released as waste
Dehydrogenase enzymes control NADH2 formation
Pyruvic
Acid
Anaerobic
Respiration
Aerobic
Respiration

9. Kreb’s Cycle

10. Hydrogen transfer system
12NADH2 are produced from glycolysis/Kreb’s cycle
Passed to a series of carriers
- the CYTOCHROME system
Carriers on stalked particles on the cristae
These use H+ ions from NADH2
- ions form ATP from ADP +Pi
This is oxidative phosphorylation
Each NADH2 forms 3ATP
Glucose produces a gain of 38ATP
- 2 from glycolysis, 36 from aerobic respiration
CRISTAE
STALKED
PARTICLES

11. Role of oxygen Accepts the final hydrogen to make water
Controlled by cytochrome oxidase
Without oxygen process cannot go beyond glycolysis

12. Anaerobic Respiration
Glucose only partially broken down
Oxygen absent
Only glycolysis occurs
Net gain of 2ATP only
Alternative pathway occurs
If oxygen returns, lactic acid converted back into pyruvic acid
- oxygen debt repaid
Pyruvic acid then enters aerobic pathway
Oxygen