photosynthesis and respiration Flashcards
Describe glycolysis
Glycolysis takes place in cytoplasm
Glucose phosphorylated
- using 2 phosphates from 2 ATP molecules
Hydrolysed to form 2 triose phosphate
(1x = glucose phosphate, 2x = hexose bisphosphate)
Triose phosphate oxidised (removal of hydrogen)
Hydrogen transferred to NAD to form NADH
2 pyruvate molecules made
Substrate level phosphorylation produces 2 ATP
Describe link reaction
Pyruvate is oxidised and decarboxylated
to form acetate
Hydrogen removed is attached to NAD to form NADH
CO2 released
Acetate is bound to Coenzyme A
Describe Krebs cycle
Occurs in the matrix of mitochondria
acetylcoenzyme A reacts with 4c molecule
- coenzyme A released (back to link)
= 6c molecule
decarboxylated and oxidised
- releases CO2 and reduces NAD to NADH
= 5c molecule
decarboxylated and oxidised again
- releases CO2 and reduces NAD to NADH
= 4c molecule
oxidised
- ATP released by substrate level phosphorylation
- NAD reduced to NADH
- FAD reduced to FADH
= 4c molecule again
Describe oxidative phosphorylation
Krebs cycle / link reaction produces NADH and FADH
happens in matrix and intermembrane space (space between inner and outer membrane)
chemiosmosis
- NADH and FADH oxidised into NAD and FAD
- Releases hydrogen atoms - split into protons and electrons - Electrons released pass along electron transport chain (made of electron carriers)
- electrons lose energy at each carrier, released
- energy used to pump protons from matrix to intermembrane space
- concentration of protons now higher in intermembrane space
- forms electrochemical gradient - protons move down gradient into matrix through ATP synthase
- synthesises ATP from ADP and Pi
electrons protons and oxygen left in matrix make water
Anaerobic respiration in animals (+ bacteria)
Forms lactate and NAD
- Glycolysis
- Pyruvate reduced to lactate
Uses NADH —> NAD oxidised
Production of NAD means glycolysis can continue in low oxygen
Small amount of ATP can be produced
Anaerobic respiration in plants and yeast
Forms ethanol and NAD
- glycolysis
- Pyruvate decarboxylated to ethanal (releases CO2)
- ethanal reduced to ethanol (oxidises NADH to NAD)
chemiosmosis
production of ATP from movement of H+ ions (protons) across a membrane, due to electrons in transport chain
products of glycolysis
2 ATP
2 NADH
2 pyruvate
products of link reaction
NADH
CO2 released
Acetyl CoA
no ATP
products of Krebs cycle
coenzyme A - used in link
NADH
FADH
used in OP
ATP
CO2
products of oxidative phosphorylation
NAD
FAD
ATP
3 respiratory substrates
Glucose
Amino acids
Glycerol and fatty acids from lipids
How are amino acids used as respiratory substrates?
Deaminated
= Pyruvate
Creates 4/5c compounds used in Krebs cycle
How are glycerol and fatty acids used a respiratory substrates?
Glycerol phosphorylated = triose phosphate
Fatty acids converted into acetyl
structure of mitochondria related to respiration
inner membrane
- site of electron transport chain
- location of ATP synthase
inter membrane space - between inner and outer
- low pH due to ions