Respiration Flashcards
What is the reason for respiration?
To produce ATP
What are the stages of aerobic respiration?
Glycolysis, link reaction, Krebs cycle, electron transport chain
What is the first stage of anaerobic and aerobic respiration?
Glycolysis
Where does glycolysis occur?
The cytoplasm
What occurs during glycolysis?
- Phosphorylation of glucose to glucose phosphate, using ATP, to produce triose phosphate.
- Oxidation of triose phosphate to pyruvate with a net gain of 2 ATP and 2 reduced NAD
What happens to the pyruvate?
It enters the mitochondrial matrix by active transport
What happens in the link reaction?
Pyruvate is oxidised to acetate, producing reduced NAD. Acetate then combines with coenzyme A in the link reaction to produce acetylcoenzyme A.
What happens in the krebs cycle?
- Acetylcoenzyme A reacts with a four-carbon molecule, releasing coenzyme A and producing a six-carbon molecule that enters the krebs cycle.
- In a series of oxidation-reduction reactions, the Krebs cycle generates reduced NAD and FAD coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost.
What happens to the reduced NAD and FAD?
- They are used in the electron transport chain where synthesis of ATP by oxidative phosphorylation occurs.
- Electrons are transferred down the electron transfer chain.
- Energy from this is used to pump protons across the inner mitochondrial membranes.
- The protons then pass through ATP synthase embedded in these membrane, generating ATP.
Where does the electron transport chain take place?
Across the inner mitochondrial membrane
What happens in the absence of glucose?
Other respiratory substrates can be used by breaking down lipids and amino acids, the products of which can enter the Krebs cycle
What happens in the absence of oxygen?
If respiration is only anaerobic, pyruvate can be converted to ethanol or lactate using reduced NAD. The oxidised NAD produced in this way can be used in further glycolysis.
