Respiration (12) Flashcards
What are the 4 stages of aerobic respiration?
1) glycolysis
2) link reaction
3) krebs cycle
4) oxidative phosphorylation
Where does glycolysis occur?
cytoplasm
Where does the link reaction occur?
mitochondrial matrix
Where does the krebs cycle occur?
membrane of cristae
What is not required for glycolysis?
oxygen
What is glycolysis?
breakdown of hexose sugar into pyruvate
What are the 3 stages of glycolysis?
activation
splitting
oxidation
What happens during activation in glycolysis?
glucose is phosphorylated to glucose phosphate by the conversion of 2 ATP into 2 ADP, making the glucose more reactive (activating it)
What happens during splitting in glycolysis?
glucose phosphate (6C) is split into 2 triose phosphate
How many carbons is glucose phosphate?
6
How many carbons is pyruvate?
3
What happens during oxidation in glycolysis?
- 2 pairs of hydrogen atoms are removed and collected by 2 NAD
- 2 phosphate ions are removed from each triose phosphate and combine with 4 ADP, forming 4 ATP
- therefore, 2 triose phosphate are oxidised to 2 pyruvate
Draw the diagram showing glycolysis
Look at notes
Draw the diagram showing the link reaction
Look at notes
What happens to pyruvate formed during glycolysis?
enters the mitochondria via active transport for the link reaction
What is the purpose of the link reaction?
connects glycolysis to krebs cycle
What does the link reaction need?
requires presence of oxygen but does not use it
What are the 3 steps of the link reaction?
1) oxidation of pyruvate to acetate releases carbon dioxide
2) pyruvate dehydrogenase removes 2 hydrogen atoms from pyruvate, forming 1 NADH
3) acetate combines with coenzyme A (CoA) to form acetyl coenzyme A
What is the equation summarising the link reaction?
2 pyruvate + 2NAD + 2CoA > 2CO2 + 2NADH + 2 acetyl coenzyme A
What is the krebs cycle?
oxidation of acetate to carbon dioxide using a series of redox reactions
What does the krebs cycle need?
requires presence of oxygen but does not use it
For each acetate produced, what other 3 substances are produced during the krebs cycle and how?
- 2 carbon dioxide from decarboxylation
- 1 ATP by substrate-level phosphorylation
- coenzymes > 3 NADH and 1 FADH