respiration

Question 1

where does glycolysis occur?

Answer 1

cytoplasm

Question 2

where does the link reaction occur?

Answer 2

mitochondrial matrix

Question 3

where does the krebs cycle occur?

Answer 3

mitochondrial matrix

Question 4

where does the electron transport chain occur?

Answer 4

inner mitochondrial membrane

Question 5

describe the process of glycolysis

Answer 5

• Glucose is phosphorylated using 2ATP into hexose phosphate.
• The hexose phosphate splits into two triose phosphate molecules.
• The oxidation of these 2 triose phosphate
  molecules yield 2 ATP each by substrate-level phosphorylation
• Dehydrogenation
  releases 2 Hydrogen that are picked up
  by NAD. 2 pyruvate molecules are produced.

Question 6

describe the link reaction

Answer 6

• Oxidative decarboxylation of pyruvate catalysed by decarboxylase releases
  carbon dioxide.
• Dehydrogenation catalysed by dehydrogenase releases pairs of hydrogen
  atoms converting NAD to reduced NAD.
• The addition of coenzyme A forms acetyl
  CoA (2C) which enters the Krebs cycle

Question 7

describe the krebs cycle

Answer 7

• The acetate from acetyl CoA combines with a 4C compound to form a 6C
  compound.
• Decarboxylation forms a 5C compound and dehydrogenation occurs reducing NAD.
• Decarboxylation forms a 4C compound and dehydrogenation reduces NAD.
• substrate level phosphorylation giving 1 ATP.
• Dehydrogenation forming reduced FAD.
  -Dehydrogenation forming reduced NAD

Question 8

describe the electron transport chain

Answer 8

• Reduced NAD and reduced FAD deliver
  pairs of hydrogen atoms to the ETC.
• They are oxidised, delivering protons and high-energy electrons to
  proton pumps on the inner mitochondrial membrane.
• Each reduced NAD utilises all 3 proton
  pumps, releasing 3ATP.
• Each reduced FAD
  utilises only 2 proton pumps, releasing 2
  ATP.
• Oxygen is the final acceptor in the electron
  transfer chain and is reduced to water

Question 9

what is the significance of lipids during respiration?

Answer 9

• Glycerol is converted into triose phosphate for use in glycolysis.
• Fatty acids are split into 2C acetate fragments which feed into the Krebs cycle as acetyl CoA

Question 10

what is the significance of proteins during respiration?

Answer 10

• Amino acids are deaminated in the liver
  into ammonia and keto acids
• (pyruvate) is used in the link reaction while the others are fed into the Krebs cycle as intermediates

Question 11

describe anaerobic respiration in animals and bacteria

Answer 11

• Glycolysis occurs. Triose phosphate is converted to pyruvate with the release of ATP and reduction of NAD.
• Reduced NAD reduces the pyruvate, forming
  lactate.
• The oxidised NAD can again be reduced during
  glycolysis. The cycle continues

Question 12

describe anaerobic bacteria in plants

Answer 12

• Glycolysis occurs. Triose phosphate is converted to pyruvate with
  the release of ATP and reduction of NAD.
• Pyruvate is decarboxylated, releasing carbon dioxide and forming ethanal.
• Reduced NAD reduces the ethanal, forming ethanol.
• The oxidised NAD can again be reduced during
  glycolysis. The cycle continues

Question 13

what happens to any energy that is not used to synthesise ATP?

Answer 13

released as heat