12 - Respiration

Question 1

GLYCOLYSIS

Answer 1

1. glucose molecule is phosphorylated to glucose phosphate using ATP
2. each glucose phosphate is split into two TP (3C)
3. each TP is oxidised (hydrogen removed)
4. hydrogen transferred to NAD, to form reduced NAD
5. each TP molecule is converted to pyruvate (3C) in an enzyme controlled reaction
6. two ATP regenerated from ADP in the process

Question 2

LINK REACTION

Answer 2

1. pyruvate (3C) loses a CO2 and two hydrogen to be oxidised to acetate
2. the hydrogens are accepted by NAD to form reduced NAD
3. the acetate (2C) combines with CoA to produce acetylcoenzyme A

Question 3

KREBS CYCLE

Answer 3

1. acetylcoenzyme A (2C) from the link reaction combines with a 4C molecule to form a 6C molecule
2. through a series of reactions the 6C molecule loses 2 CO2 molecules and hydrogen to form a 4C molecule
3. an ATP molecule is produced as a result of substrate level phosphorylation
4. the 4C molecule can now combine with a new molecule of acetyl CoA to begin the cycle again
5. reduced coenzymes NAD and FAD are produced during the process of the link reaction and Krebs cycle

Question 4

OXIDATIVE PHOSPHORYLATION

Answer 4

1. the hydrogen atoms produced during glycolysis and Krebs cycle combie with the coenzymes NAD and FAD
2. the reduced NAD and FAD donate the electrons of the hydrogen atoms they are carrying to the first molecule in the electron transfer chain
3. the electrons pass along the electron transfer carrier molecules in a series of redox reactions
4. as the electrons move along the chain they release energy causing the active transport of protons into the inter-membranal space
5. the protons accumulate in the inter-membranal space before they diffuse back into the matrix through ATP synthase channels (chemisosmotic theory)
6. at the end of the chain the electrons combine with these protons and oxygen to form water (making oxygen the final electron acceptor)

Question 5

SEQUENCE OF RESPIRATION PROCESSES

Answer 5

glycolysis, link reaction, Krebs cycle, oxidative phosphorylation

Question 6

LOCATION OF GLYCOLYSIS

Answer 6

cytoplasm

Question 7

LOCATION OF LINK REACTION

Answer 7

matrix of mitochondria

Question 8

LOCATION OF KREBS CYCLE

Answer 8

matrix of mitochondria

Question 9

LOCATION OF OXIDATIVE PHOSPHORYLATION

Answer 9

matrix of mitochondria

Question 10

RESPIRATION OF LIPIDS

Answer 10

lipids hydrolysed to glycerol and fatty acids, glycerol then phosphorylated and converted to triose phosphate, triose phosphate enters glycolysis pathway and then Krebs cycle
fatty acids are hydrolysed into 2C fragments which are converted to acetyl CoA before entering Krebs cycle

Question 11

RESPIRATION OF PROTEINS

Answer 11

hydrolysed into amino acids, amino group is removed, resulting molecules enter respiratory pathway at different points depending on number of carbon atoms they contain

Question 12

ANAEROBIC RESPIRATION IN BACTERIA AND FUNGI

Answer 12

pyruvate + reduced NAD&raquo_space; ethanol + CO2 + oxidised NAD

Question 13

ANAEROBIC RESPIRATION IN ANIMALS

Answer 13

pyruvate + reduced NAD&raquo_space; lactate + oxidised NAD (lactate is oxidised back to pyruvate when oxygen is again available)