Core L - Respiration Flashcards
Explain why, in the absence of oxygen, pyruvate needs to be converted to lactate. (2)
- NAD regenerated
- So glycolysis can continue
- To produce ATP
Name the part of the cell where glucose is converted to pyruvate. (1)
Cytoplasm.
Name the enzyme responsible for the conversion of pyruvate to lactate. (1)
Lactate dehydrogenase.
Name the type of reaction and the type of bonds formed when glucose molecules are used to make glycogen. (2)
- Condensation / polymerisation
* Glycosidic bonds
Describe how anaerobic respiration in yeast cells differs from anaerobic respiration in mammalian cells. (4)
- Pyruvate decarboxylated
- Produce ethanal
- Reduced to ethanol
- Two steps from pyruvate
- Ethanol dehydrogenase
- Not a reversible reaction (ethanol cannot be converted back to pyruvate)
- Less energy efficient
State how RQ is calculated. (2)
Volume of carbon dioxide produced divided by volume of oxygen consumed.
Suggest what would happen to the RQ value when respiration becomes anaerobic. (1)
Above one / infinity.
Explain why ATP is needed at the start of glycolysis. (1)
Raise chemical PE of glucose (provide activation energy)
State the role of NAD in glycolysis. (1)
Removes hydrogen / hydrogen carrier / coenzyme
Name the two types of reaction that occur during the conversion of pyruvate to acetyl CoA in the link reaction. (2)
- Dehydrogenation
* Decarboxylation
Describe what happens to the hydrogen released during the link reaction. (2)
- Accepted by NAD
- Passed to ETC
- For oxidative phosphorylation
- Proton pump / chemiosmosis
Explain why ATP is regarded as the universal energy currency in organisms. (5)
- Found in all organisms
- Loss of phosphate (hydrolysis) leads to 30.6 kJ of energy release
- Reversible reaction
- Small packets of energy
- Small, water soluble so can move around cell
- Used by cells as immediate energy donor
- Link between energy yielding and energy requiring reactions
- High turnover
- Active transport, muscle contraction, Calvin Cycle
Describe how anaerobic respiration in mammalian cells differs from anaerobic respiration in yeast cells. (3)
- Lactate produced / no ethanol produced
- No decarboxylation
- Single step
- Lactate dehydrogenase
- Reversible
Explain why anaerobic respiration results in a small yield of ATL compared with aerobic respiration. (3)
- Only glycolysis occurs
- Glucose not fully broken down (still contains energy)
- Pyruvate does not enter mitochondrion
- No oxygen so no final electron acceptor in ETC
- ETC stops
- No oxidative phosphorylation
Explain why glucose needs to be converted to hexose bisphosphate. (2)
- Provide activation energy
* For it to split