Respiration Weak Areas

Question 1

The group of students wanted to find out the rate of respiration of a small invertebrate, such as a woodlouse or caterpillar with that of a mung bean. Comment on the results you might expect from this experiment and the conclusions you may draw.

Answer 1

Use same mass of soda lime to absorb the CO2
Bigger syringe needed for invertebrate as they produce more CO2 - higher metabolic demand
Keep temp high and constant
Repeat experiment
Keep the mass of the small invertebrate and the mass of the mung beans the same
Ethical use of small invertebrate
Measure distance moved of the red liquid placed in the capillary tubing
Movement would be greater in the small invertebrate

Question 2

Explain why there is only a small amount of ATP made up the students mass

Answer 2

ATP is constantly recycled
ATP hydrolysed to ADP to release energy
ATP is unstable
ATP is used up immediately after produced and only produced in small quantities to reduce waste

Question 3

Which amino acids have the highest RQ

Answer 3

The ones with the highest proportion of O2 atoms in its structure

Question 4

Summarise the importance of coenzymes in respiration (6)

Answer 4

Coenzyme A :
- transfers acetate from link reaction to the Kreb cycle

ADP/ ATP :
- phosphorylation of glucose to hexose bisphosphate
- removal of phosphate group from triose phosphate to form pyruvate
- formation of ATP in substrate level phosphorylation
- formation of ATP from oxidative phosphorylation

NAD :
- Coenzymes that transfer electrons and H + ions to inner membrane to support chemiosmosis
- removal of H + ions from pyruvate in glycolysis
- removal of H+ from pyruvate in link reaction
- reduction of pyruvate in lactate fermentation
- reduction of ethanol in alcoholic fermentation

FAD:
- oxidation of intermediates in the Kreb cycle

Question 5

Explain how having a larger number of proton pores in the inner mitochondrial membrane would result in a person being less likely to gain weight

Answer 5

Protons leak back into the matrix from the inter membrane space over the inner membrane of the mitochondria
Reduces yield of ATP from chemiosmotic gradients
Less ATP made in oxidative phosphorylation
Energy from chemiosmosis decoupled from ATP synthesis
Food not converted to ATP efficiently
Fats could be respired for energy instead of carbs
Energy yield from aerobic respiration is reduced per molecule of glucose

Question 6

What properties of the mitochondrial inner membrane allow chemiosmosis to occur

Answer 6

Mostly impermeable to H+ ions means that electron transport chain has to generate energy for proton pumps to create H+ gradient
ATP synthase is a protein that H+ ions diffuse back into the matrix through from the inter membrane space allowing ATP to be produced from ADP