3. Glycolysis, the Pasteur effect and Cori cycle

Question 1

Cori cycle

Answer 1

Question 2

Explain the pasteur effect:

Answer 2

The pasteur effect is the inhibition of anaerobe glycolysis by respiration. NADH+H+ is produced when glyceraldehyde 3-p is dehydrogenased to 1,3-dihydrophosphoglycerate. If O2 is present NADH+H+ will be oxidized with O2 through the respiratory chain. If not (anaerobe) NADH+H+ is used to produce lactate from pyruvate.

Question 3

what are the exceptions of the pasteur effect?

Answer 3

Fetus, retina, cancer - accumulate lactate aerobically

Question 4

Location, regulation, energy balance and importance of glycolysis:

Answer 4

Location: Cytoplasm, aerobe - cardiac muscle, brain, liver
anerobe - RBC, skeletal muscle

Regulation: Phosphofructokinase-1
+AMP,ADP
-High levels of ATP and citrate

Energy balance: ?

Importance of glycolysis: Glycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released is used to form the high-energy molecules ATP and NADH.

Question 5

Types of glycolysis:

Answer 5

There are two phases of the synthesis, the preparatory phase and the energy conserving phase.

1. The first five steps are regarded as the preparatory (or investment) phase, since they consume energy to convert the glucose into two three-carbon sugar phosphates
2. The second half of glycolysis is known as the pay-off phase, characterised by a net gain of the energy-rich molecules ATP and NADH. Since glucose leads to two triose sugars in the preparatory phase, each reaction in the pay-off phase occurs twice per glucose molecule. This yields 2 NADH molecules and 4 ATP molecules, leading to a net gain of 2 NADH molecules and 2 ATP molecules from the glycolytic pathway per glucose

Question 6

steps og glycolysis:

Answer 6