Respiration

Question 1

Aerobic respiration symbol equation

Answer 1

C6H12O6 + 6O2 —> 6CO2 + 6H2O + energy

Question 2

Anaerobic respiration word equation

Answer 2

(Plants) glucose —> carbon dioxide + ethanol + energy
(Animals) glucose —> lactate + energy

Question 3

Mitochondria structure (+ function)

Answer 3

• Cristae (increase SA for oxidative phosphorylation)
• Matrix (contains enzymes for link reaction and Krebs cycle)

Question 4

Aerobic glycolysis

Answer 4

• Takes place in the cytoplasm
• Glucose is phosphorylated using ATP
• Triose phosphate is oxidised to form pyruvate
• NAD is reduced to NADH
• Pyruvate is actively transported into the mitochondria for link reaction
• Net yield is 2 ATP and 2 NADH

Question 5

Anaerobic glycolysis

Answer 5

• Takes place in the cytoplasm
• Glucose is phosphorylated using ATP
• Triose phosphate is oxidised to form pyruvate
• NAD is reduced to NADH
• Pyruvate is reduced using NADH to form lactate (mammals + bacteria) or ethanol and carbon dioxide (plants + yeast)
• NAD is regenerated by reducing pyruvate

Question 6

The link reaction

Answer 6

• Takes place in matrix of mitochondria
• Pyruvate is dehydrogenated and decarboxylated to form acetate
• Acetate combines with coenzyme A to form acetyl coenzyme A
• Yields 2 CO2 and 2 NADH per glucose

Question 7

The Krebs cycle

Answer 7

• Takes place in matrix of mitochondria
• Acetyl coenzyme A joins a 4C compound to form a 6C compound
• Coenzyme A is recycled
• 6C compound is dehydrogenated and decarboxylated to form 4C compound
• ATP undergoes substrate level phosphorylation
• Yields 3 NADH, 1 ATP, 1 FADH, 2 CO2 per cycle

Question 8

Oxidative phosphorylation

Answer 8

• Electrons and protons are released from reduced NAD and FAD
• Electrons flow along electron transport chain in a series of redox reactions, releasing energy
• Energy used to actively transport protons (H+) into intermembrane space, forming an electrochemical gradient
• H+ move down their electrochemical gradient, through ATP synthase into the matrix, joining ADP + Pi —> ATP
• Oxygen is the final electron acceptor (combines with electrons and protons to form water)

Question 9

Number of ATP molecules produced in aerobic respiration

Answer 9

32 (2.5 per NADH, 1.5 per FADH)

Question 10

Measuring rate of aerobic respiration

Answer 10

• Use same species of woodlice
• Range of at least 5 different temperatures
• Accurately measure mass of woodlice
• Repeat 5 times and calculate mean
• CO2 absorbed by sodium hydrogen carbonate
• Volume decreases, pressure decreases
• Bubble moves to left

Question 11

Measuring rate of anaerobic respiration

Answer 11

• Use same species of yeast
• Range of at least 5 different temperatures
• Accurately measure mass of yeast
• Repeat 5 times and calculate mean
• CO2 produced by anaerobic respiration
• Volume increases, pressure increases
• Bubble moves to right