Respiration Flashcards
where does glycolysis occur?
in the cytoplasm of cells
what are the two stages in glycolysis?
phosphorylation and oxidation
what happens in glycolysis?
2 phosphates are added to the glucose molecule which then splits into triose phosphate. The triose phosphate loses 2H+ forming pyruvate.
where does the pyruvate go after glycolysis?
actively transported into the matrix of the mitochondria
what happens in the link reaction?
pyruvate loses one carbon to CO2, this is oxidised to form acetate then combines with CoenzymeA.
what happens in the Kreb’s cycle?
acetyl coconzyme A combines with a 4-carbon molecule, loses 2 carbons to CO2 and 4H+ to NAD and FAD.
what happens in oxidative phosphorylation?
Hydrogen atoms from NAD and FAD are released and split into H+ and e-. These are passed along an electron transport chain releasing energy which pumps protons into the intermembrane space producing an electrochemical gradient. The protons move down the gradient through ATP synthase channels producing ATP.
What does aerobic respiration produce?
CO2, water and ATP
What does anaerobic respiration produce?
Lactate, CO2 and a little ATP
What is the energy yield from glycolysis?
2 molecules of ATP
2 molecules reduced NAD
2 molecules of pyruvate
where are the enzymes for the glycotic pathway found?
In the cytoplasm of cells and so glycolysis does not require any organelle or membrane
Why does the pyruvate need to be converted into lactate or ethanol during anaerobic respiration?
To re-oxidise the NAD so that glycolysis can continue and prevent the redNAD building up.
What is the overall equation for the link reaction?
pyruvate + NAD + CoA –> acetyl CoA + redNAD + CO2
What are the four important roles the Kreb’s cycle has in organisms?
- Breaks down macromolecules into smaller ones,
- Produces hydrogen atoms that are carried by NAD to the electron transfer chain, providing energy for oxidative phosphorylation,
- It regenerates the 4-carbon molecule,
It is a source of intermediate compounds used by cells in the manufacture of other important substances such as fatty acids.
What would happen without oxygen?
The hydrogen ions and electrons would ‘back-up’ along the chain and the process of respiration would come to a halt.
Why are the electrons passed down an electron transfer chain?
Allows the energy to be released gradually, minimising heat loss.
What is substrate level phosphorylation?
The direct transfer of phosphate from a respiratory intermediate to ADP to produce ATP.
What is oxidative phosphorylation?
the indirect linking of energy from phosphate to ADP to produce ATP involving energy from the hydrogen atoms that are carried on NAD and FAD.
Explain why converting pyruvate to lactate allows ATP to be produced.
Regenerates NAD from reduced NAD
So it can continue to be used in glycolysis.
