INTRODUCTORY BASIC SCIENCES STREAM – AL/2008 BATCHBiochemistry - 2nd Term Tutorials

Tutorial -1

1.1 State the difference between,(a) substrate level phosphorylation and oxidative phosphorylation.(b) inhibitors and uncouplers of electron transport chain (ETC) & oxidative phosphorylation.

1.2 Lactate is the end product of glycolysis under anaerobic conditions. Explain.

2. Taking pyruvate dehydrogenase as an example explain how,(a) covalent modification(b) energy status of the cell

regulate this enzymatic step.

3 Explain the following(a) The importance of the non-oxidative phase of the HMP (Hexose Monophosphate Pathway).(b) The role of the HMP in macrophages.

4.(a) Compare glycogenolysis in muscle and Iiver(b) What nutritional advice is given in liver glycogen deficiency?

Tutorial – 2

1. Explain the role of(a) Citrate(b) Acetyl CoAin fatty acid biosynthesis.

2. Explain how long chain fatty acids are taken into the mitochondrion for oxidation and state how the above process is regulated.

3. Explain the importance of ketone bodies as a source of energy in prolonged fasting.

4. List the differences between Low density lipoproteins (LDL) and high density lipoproteins (HDL) with regard to their,

(a) major constituents(b) functions

5.(a) Explain the importance of glutamate dehydrogenase in amino acid metabolism.(b) Give the biochemical basis for the toxicity of ammonia.(c) How is ammonia transported from muscle to liver?

Tutorial -3

1. Explain the regulation of cholesterol biosynthesis.

2. In a person fasting for 3-5 days, the rate of gluconeogenesis is increased. Explain how this is achieved by(a) substrate availability(b) activation and inhibition of enzymes

3. How is the urea cycle regulated? What is the effect of ingestion of a high protein diet on the excretion of urinary nitrogenous compounds? How and why do these changes occur?

4. Explain how intracellular cholesterol concentration of extra hepatic tissues is regulated.

5. Explain the following:(a) Creatinine clearance test.(b) The importance of creatine phosphate as an energy reserve.

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