metabolic pathways and ATP production

Question 1

what do transport shuttles achieve

Answer 1

allow NAD+ to regenerate for glycolysis

Question 2

where is the glycerol-phosphate shuttle

Answer 2

skeletal muscle and brain

Question 3

glycerol-phosphate shuttle: cytoplasmic reaction

Answer 3

NADH + H+ → NAD+; e- + DHAP → glycerol-3-phosphate; e- transferred to E-FAD to form E-FADH2; catalysed by glycerol-3-phosphate dehydrogenase and cofactors

Question 4

glycerol-phosphate shuttle: membrane-bound reaction

Answer 4

Q-coenzyme + E-FADH2 → E-FAD + QH2

Question 5

glycerol-phosphate shuttle diagram

Answer 5

diagram from metabolism 4

Question 6

where is the malate-aspartate shuttle

Answer 6

liver, kidney, heart

Question 7

malate-aspartate shuttle: NADH reaction

Answer 7

NADH(cyt) + NAD+(mt) → NAD+(cyt) + NADH(mt)

Question 8

malate-aspartate shuttle: first step

Answer 8

H- transferred to oxaloacetate, forming malate via MDH

Question 9

malate-aspartate shuttle: second step

Answer 9

malate transported into mitochondria (via a-ketoglutarate transporter) where is is reoxidised by NAD+ to produce oxaloacetate

Question 10

malate-aspartate shuttle: third step

Answer 10

oxaloacetate is converted to aspartate and leaves bia the glutamate-aspartate transporter

Question 11

malate-aspartate shuttle: transamination reaction

Answer 11

glutamate (IN) + oxaloacetate → a-ketoglutarate (OUT) + aspartate (OUT)

Question 12

malate-aspartate shuttle diagram

Answer 12

diagram from metabolism 4