ASSIGNMENT

Per kelompok (max 5 orang)

Ditulis di kertas bergaris

Dikumpulkan waktu kuliah berikutnya

Bioenergetic

1. Explain how a metabolic pathway can

contain an energetically unfavorable

reaction yet still be occur!

2. What general factors contribute to the

high phosphoryl-group transfer of ATP

3. The synthesis of the activated form of acetate (acetyl-

CoA) is carried out in an ATP-dependent process:

a. The G for the hydrolysis of acetyl-CoA to acetateand CoA is 32.2 kJ/mol and that for hydrolysis of ATP to

AMP and PPi is 30.5 kJ/mol. Calculate G for the ATP

dependent synthesis of acetyl-CoA.

b. Almost all cells contain the enzyme inorganic

pyrophosphatase, which catalyzes the hydrolysis of PPi

to Pi. What effect does the presence of this enzyme

have on the synthesis of acetyl-CoA? Explain.

Glycolysis

1. Why do muscles need to generate ATP

under aerobic and anaerobic

conditions?

2. Why is it more sensible for

phosphofructokinase to be an important

control step, rather than hexokinase

3. Suppose you discovered a mutant

yeast whose glycolytic pathway was

shorter because of the presence of a

new enzyme catalyzing the reaction:

Would shortening the glycolytic

pathway in this way benefit the cell?

Explain.

Gluconeogenesis

1. What is the cost (in ATP equivalents) of

transforming glucose to pyruvate via

glycolysis and back again to glucose via

gluconeogenesis?

2. When gluconeogenesis will occurs in our

body?

The citric acid cycle1. Why is the isomerization of citrate to

isocitrate a necessary step of the citric

acid cycle?

2. Explain why a GTP is energetically

equivalent to an ATP in metabolism!

3. What reaction serves to link glycolysis

and the citric acid cycle?

4. Are the acetyl carbons that enter the

citric acid cycle the exact same carbons

that leave as CO2? Briefly explain.