Respiration Exam Questions

Question 1

Describe the formation of acetyl coenzyme a in the link reaction (3)

Answer 1

• Oxidation of pyruvate and carbon dioxide releases
• the addition of coenzyme a in the Krebs cycle
• reduction of Nad

Question 2

Describe the role of coenzymes and carrier proteins in the synthesis of ATP

Answer 2

Nad is reduced
Electrons transferred in redox reactions
Energy made available as electrons are passed on
This energy is used to synthesise atp to adp and pi

Question 3

Describe the mechanism by which ATP is formed in the mitochondria

Answer 3

• substrate level phosphorylation in the krebs cycle
• produces reduced Nad and fad
• electrons are released from the reduced coenzymes
• election pass along the electron transport
  chain
• releasing energy
• which provides energy for the condensation reaction of adp + pi

Question 4

Suggest three reasons why the apparatus was left for 10 minutes

Answer 4

Equilibrium can be reached
Allows the respiration rate to be stabilised
Allow for pressure change

Question 5

Aerobic respiration produces more atp per molecule of glucose than anaerobic respiration

Answer 5

Oxygen is the final electron acceptor in oxidative phosphorylation which only occurs in aerobic respiration

Question 6

Suggest why the rate of gas production decreased between 50 and 60 minuyes

Answer 6

Concentration of glucose decreases so becomes a limiting factor