Processing of Carbohydrates

Question 1

where does glycolysis occur?

Answer 1

cytosol of all cells

Question 2

what are the control points/enzymes

Answer 2

irreversible steps: hexokinase/glukinase, phosphofructokinase (rate limiting step) and pyruvate kinase

Question 3

What is the preparative phase of glycolysis?

Answer 3

glucose –> furctose 1,6, bisphosphate

Question 4

what is the generating phase?

Answer 4

fructose 1,6 bisphosphate –> pyruvate + 5-7 ATP + NADH

Question 5

Glucagon’s effects on glycolysis

Answer 5

Regulates fructose 2,6 bisphosphate levels - activates glycolysis, inhibits gluconeogenesis
High glucagon= inhibited glycolysis

Question 6

Glycogen conversion

Answer 6

glucose-6-phosphate –> glucose 1-phosphate (needs primer= glycogenin)
Control enzyme: glycogen synthase
Glycogen phosphorylase removes glucose units so can enter glycolysis} liver and kidney only, requires ATP

Question 7

Fatty acids

Answer 7

in cytosol of liver (also adipose tissue and breast tissue in lactation)
Citrate–> acetyl CoA –> Fa (malonyl CoA) } requires ATP and NADH} control step
acetyl-CoA can’t cross mitochondrial membrane
3Fa + glycerol-3-phosphate –> triacylglycerol } in ER
stored in cytosol of adipose tissue and packed into VLDL in liver

Question 8

AMPK

Answer 8

key enzyme in energy metabolism in heart, adipose, liver, muscle} starvation –> increased degradation