Respiration

Question 1

Glycolysis

Answer 1

• In the cytoplasm
• Phosphorylation of glucose using ATP to make it more reactive;
• Lysis of the phosphorylated glucose intermediate to form Triose Phosphate
• Oxidation from TP to pyruvate by losing H+ and e-
• Net gain of 2 ATP;
• NAD reduced/NADH formed

Question 2

Link reaction

Answer 2

• In the mitochondrial matrix
• Pyruvate is oxidised using coenzyme A
• CO2 released
• NAD is reduced
• Acetyl CoA is formed

Question 3

Kreb cycle

Answer 3

• Acetyl CoA reacts with a 4C acceptor molecule
• The 6C intermediate is decarboxylated and oxidised,
removing CO2 and reducing NAD
• The resulting 5C intermediate is also decarboxylated and oxidised removing CO2 and reducing 2xNAD, reducing FAD and generating 1x ATP in a series of REDOX reactions.
• Until the original 4C acceptor is formed again.

Question 4

Oxidative phosphorylation

Answer 4

• FADH and NADH are oxidised and lose e- and H+
• The e- are passed from carrier protein to carrier protein in the mitochondria inner
membrane in a series of redox reactions
• This releases energy
• The energy is used to pump H+ through the membrane into the inner membrane space building a chemiosmotic gradient
• H+ moves back through the membrane through ATP synthase
• ADP+Pi→ATP
• Oxygen is the terminal electron acceptor forming water

Question 5

Anaerobic respiration in mammals

Answer 5

• Pyruvate is reduced to lactate • NADH is oxidised during this
process
• This prevents NAD running out and allows ATP to continue being made in glycolysis

Question 6

Anaerobic respiration in yeast

Answer 6

• Pyruvate is reduced to ethanal then ethanol
• NADH is oxidised during this process
• CO2 is produced
• This prevents NAD running out and allows ATP to continue being made in glycolysis