Download Respiration

Recap: structure of ATP
P
P
P
ribose
guanine
inorganic
phosphate
deoxyribose
thymine
organic
phosphate
nicotinamide
cytosine
adenine
flavine
Recap: where in the cell?
1. Glycolysis
1. Phosphorylation
2. Oxidation
2. Link reaction
3. Krebs cycle
4. Oxidative
phosphorylation
Recap: glycolysis
Recap: link reaction
Recap: Krebs cycle
Enzymes
• Glycolysis:
– Phosphofructokinase
• Krebs cycle:
– Decarboxylases
– Dehydrogenases
Regulatory enzymes
glucose
↑ ATP
↑ citrate
phosphofructokinase
enzyme
pyruvate
Krebs
cycle
↑ ADP
↓ ATP
↓ citrate
How much ATP has been produced?
• Glycolysis:
• Link reaction:
• Krebs cycle:
Is this enough???
The electron transport chain
The electron transport chain
1. Hydrogen atoms released from NADH and FADH as
they are oxidised
2. Hydrogen atoms split into protons and electrons
3. Electrons move along the electron transport chain,
losing energy at each carrier
4. Energy is used to pump protons into intermembrane
space forming an electrochemical gradient
5. Protons move down electrochemical gradient back to
matrix via ATP synthase
6. Movement of protons drives synthesis of ATP from ADP
and inorganic phosphate
7. Protons, electrons and oxygen combine to form water,
the final electron acceptor
Evidence for chemiosmosis
1. pH of intermembrane space is lower than pH of
matrix
– Proton gradient exists between intermembrane space and
matrix
2. Artificial vesicles created with proton pump proteins
resulted in ↓ pH in vesicle
– Proton gradient can be used to synthesise ATP
3. Mitochondria in pH8 solution produced no ATP
– Proton gradient can be used by mitochondria to make ATP
4. Uncouplers destroyed proton gradient in
mitochondria
– Proton gradient is required by mitochondria to make ATP
How much ATP?
• Oxidative phosphorylation makes ATP
using energy from NADH and FADH
• 1 NADH → 2.5 ATP
• 1 FADH → 1.5 ATP
More cutbacks:
In 1997 1 NADH
→ 3 ATP and 1
FADH → 2 ATP!
How much ATP?
Stage of respiration
Molecules produced
Number of ATP molecules
Glycolysis
Link reaction (x2)
Krebs cycle (x2)
Total ATP =
Anaerobic respiration
glucose
pyruvate
carbon
dioxide +
ethanal
ethanol
lactic
acid
Aerobic and anaerobic respiration
Aerobic
Anaerobic
• Where?
• Where?
• Is oxidation complete?
• Is oxidation complete?
• What are the waste
products?
• What are the waste
products?
• How much energy?
• How much energy?