[OLD] Respiration - Exam Questions Flashcards
Give two advantages of ATP as an energy-storage molecule within a cell.
It releases energy in a simple one step reaction.
It releases energy in small amounts.
Describe how NAD is regenerated in anaerobic respiration in yeast cells. (1)
Formed when NADH used to convert pyruvate to ethanol.
Pyruvate is formed in the breakdown of glucose during respiration. When there is sufficient oxygen, this pyruvate is fully broken down. Name two substances formed from the pyruvate. (1)
Water ATP NADH FADH CO2
If there is shortage of oxygen in muscle cells during exercise, some pyruvate is converted into lactate. Explain why muscles become fatigued when insufficient oxygen is a available. (2)
Lactic acid lowers pH
Enzymes inhibited
Some lactate is oxidised to pyruvate by muscles when they are well-supplied with oxygen. Suggest an advantage of the lactate being oxidised in the muscles. (2)
Lactate/pyruvate is an energy source.
Muscles have increased ATP supply.
Restores pH levels.
Apart from respiration, give three uses of ATP in a liver cell. (3)
active transport. protein, glycogen, DNA, RNA, lipid, urea, or cholesterol synthesis. source of energy. phagocytosis. bile production. cell division / mitosis.
Describe how acetylcoenzyme A is formed in the link reaction. (2)
Pyruvate is oxidised and CO2 is released.
It then binds to coenzyme A.
Explain why converting pyruvate to lactate allows the continued production of ATP during anaerobic respiration. (2)
Regenerates oxidised NAD
Used in glycolysis
Suggest one advantage of converting lactate back to pyruvate when muscles are well supplied with oxygen. (1)
The pyruvate can be used in aerobic respiration.
OR
Lactate is toxic / harmful / causes muscle fatigue.
When glucose is respired what happens to the energy which is not incorporated into ATP? (1)
released as heat.
