Anaerobic Respiration and Respiratory Quotients

Question 1

When do plants and animals respirate anaerobically?

Answer 1

When there is a lack of oxygen

Question 2

Describe the process of Lactate Fermentation in animals?

Answer 2

• Glycolysis takes place
• 2 Pyruvate, 2 ATP and 2 NADH formed
• NAD regneration converts NADH to NAD
• Lactate dehydrogenase forms 2 Lactate molecules

Question 3

Is lactate fermentation reversible?

Answer 3

Yes because lactate dehydrogenase (enzyme) can carry out the reverse reaction

Question 4

Describe the process of alcoholic fermentation in plants?

Answer 4

• Glycolysis takes place
• 2 Pyruvate, 2 ATP and 2 NADH formed
• Decarboxylation produces 2CO2 and Ethenal
• Dehydrogenation forms Ethanol and NAD
• Alcohol dehydrogenase used (enzyme)

Question 5

Is alcoholic fermentation reversible?

Answer 5

No, alcohol dehydrogenase cannot carry out reverse reaction

Question 6

Why is oxygen important for respiration?

Answer 6

Electron transport chain cannot happen is there’s no oxygen to act as the final electron and H+ acceptor

Question 7

What are respiratory substrates?

Answer 7

Molecules in which energy can be liberated to produce ATP in a living cell

Question 8

What are the 3 respiratory substrates?

Answer 8

• Glucose
• Lipids
• Protein

Question 9

How are fatty acids used in the Krebs cycle?

Answer 9

Can be used instead of pyruvate to make 2 acetyl coenzyme A molecules

Question 10

How are amino acids used in the Krebs cycle? (3)

Answer 10

• Deaminated
• Converted into pyruvate and enters link reaction
• Converted into acetate and enter Krebs’ cycle

Question 11

How do you calculate Respiratory Quotients?

Answer 11

Carbon dioxide given off ÷ oxygen taken in

doesn’t need to be volume as long as they’re both the same units

Question 12

How is RQ data collected? (4)

Answer 12

• Use a respirometer
• NaOH absorbs CO2 from air in the apparatus
• Germinating seeds use oxygen and so pressure decreases
• Manometer fluid moves towards it as CO2 tries to diffuse to it

Question 13

Why does an organism respire anaerobically?

Answer 13

When there is a lack of oxygen

Question 14

Compare anaerobic respiration respiration to aerobic.

Answer 14

• Both have glycolysis
• In aerobic, continues to link reaction, krebs cycle and oxidative phosphorylation
• In anaerobic, goes to lactate fermentation