3.3 respiration
Glucose + oxygen= carbon dioxide + energy + water
Aerobic respiration is split into 4 main stages
Glycolysis Cell cytoplasm
Link reaction Matrix
Krebs cycle Matrix
ETC Inner mitochondrial membrane
Glycolysis:
Because it occurs in cytoplasm, only stage which can occur with or without oxygen
Process:
1. Phosphate added to glucose using ATP and the enzyme Kinase. Enzyme is added to
6th carbon so its called glucose-6-phosphate
2. Isomerisation occurs to create fructose-6-phosphate
3. Second phosphate added using ATP and kinase. It adds to the 1 st carbon so fructose
1,6 diphosphate is made
4. This is a high energy highly unstable molecule so it splits into two molecules of triose
phosphate. For every glucose feeding in at the top, two of everything will be made
5. 2NADH is made
6. 2ATP is made by substrate level phosphorylation
7. This repeats and 2ATP is made again by substrate level phosphorylation
8. Final product is 2x 3carbon pyruvates
Overall, there’s a net production of 2ATP molecules because although 4 were made, 2 ATPs
were used in the process at stages 1 and 3
2NADH are made and (in aerobic respiration) they will go onto the ETC to make ATP by
oxidative phosphorylation/chemiosmosis
Link Reaction:
Links glycolysis to Krebs cycle
Reduces 3 carbon pyruvate into 2 carbon acetyl CoA
Carbon that is lost in the reduction is released as CO2
This is a decarboxylation reaction and uses decarboxylase enzyme
It produces 2NADH that will go onto electron transport chain
Krebs cycle:
Cycle of reactions discovered by Hans Kreb
This occurs in matrix of mitochondrion because there are lots of dissolved enzymes present
like decarboxylase and dehydrogenase
The Krebs cycle needs to go around twice because for every glucose entering glycolysis, 2
pyruvate are made and 2 acetyl CoA are made
Process:
1. 2 carbon acetyl CoA made in link reaction is accepted by a 4 carbon compound to
make a 6 carbon compound
2. 6 carbon compound converted into 5 carbon compound by decarboxylation
producing CO2. Molecule of NADH is made
Glucose + oxygen= carbon dioxide + energy + water
Aerobic respiration is split into 4 main stages
Glycolysis Cell cytoplasm
Link reaction Matrix
Krebs cycle Matrix
ETC Inner mitochondrial membrane
Glycolysis:
Because it occurs in cytoplasm, only stage which can occur with or without oxygen
Process:
1. Phosphate added to glucose using ATP and the enzyme Kinase. Enzyme is added to
6th carbon so its called glucose-6-phosphate
2. Isomerisation occurs to create fructose-6-phosphate
3. Second phosphate added using ATP and kinase. It adds to the 1 st carbon so fructose
1,6 diphosphate is made
4. This is a high energy highly unstable molecule so it splits into two molecules of triose
phosphate. For every glucose feeding in at the top, two of everything will be made
5. 2NADH is made
6. 2ATP is made by substrate level phosphorylation
7. This repeats and 2ATP is made again by substrate level phosphorylation
8. Final product is 2x 3carbon pyruvates
Overall, there’s a net production of 2ATP molecules because although 4 were made, 2 ATPs
were used in the process at stages 1 and 3
2NADH are made and (in aerobic respiration) they will go onto the ETC to make ATP by
oxidative phosphorylation/chemiosmosis
Link Reaction:
Links glycolysis to Krebs cycle
Reduces 3 carbon pyruvate into 2 carbon acetyl CoA
Carbon that is lost in the reduction is released as CO2
This is a decarboxylation reaction and uses decarboxylase enzyme
It produces 2NADH that will go onto electron transport chain
Krebs cycle:
Cycle of reactions discovered by Hans Kreb
This occurs in matrix of mitochondrion because there are lots of dissolved enzymes present
like decarboxylase and dehydrogenase
The Krebs cycle needs to go around twice because for every glucose entering glycolysis, 2
pyruvate are made and 2 acetyl CoA are made
Process:
1. 2 carbon acetyl CoA made in link reaction is accepted by a 4 carbon compound to
make a 6 carbon compound
2. 6 carbon compound converted into 5 carbon compound by decarboxylation
producing CO2. Molecule of NADH is made
