III. Keys

PRACTICAL LESSON 1

CARBOHYDRATES: BIOLOGICAL FUNCTIONS AND CLASSIFICATION. METABOLIC PATHWAY OF CARBOHYDRATES

GLYCOGEN METABOLISM

1.E.

2.A.

3.C.

4.E.

5.E.

6.C.

7.C.

8.D.

9.E.

10.C

PRACTICAL LESSON 2

GLYCOLYSIS: REACTION, REGULATION, ENERGY BALANCE. AEROBIC OXIDATION OF GLUCOSE

1. C.

2. A.

3.D

4.B.

5.D.

6.E

7.D. Hexokinase, phosphofructokinase and pyruvate kinase are all irreversible and are the regulated steps in glycolysis. The conversion of glucose to lactate (anaerobic glycolysis) is a process that does not involve a net oxidation or reduction and, thus, oxygen is not required. Glucokinase (not hexokinase) is important in hepatic glucose metabolism only in the absorptive period following consumption of a carbohydrate-containing meal. Fructose 2.6-bisphosphate is a potent activator (not inhibitor) of phosphofructokinase. The conversion of glucose to lactate yields two ATP but no net production of NADH.

8.C. Phosphofructokinase is the pace-setting enzyme of glycolysis. It is inhibited by ATP and citrate, uses fructose 6-phosphate as substrate, and catalyzes a reaction that is far from equilibrium. The reaction is activated by fructose 2.6-bisphosphate.

9.A. Vigorously contracting muscle shows an increased formation of lactate and an increased rate of pyruvate oxidation compared with resting skeletal muscle. The levels of AMP and NADH increase, whereas change in the concentration of fructose 2.6-bisphosphate is not a key regulatory factor in muscle.

10.C. Decreased lactate production in the erythrocyte indicates a defect in glycolysis. Among patients exhibition genetic defects of glycolytic enzymes, about 95% show a deficiency in pyruvate kinase, and 4% exhibit phosphoglucose isomerase deficiency.

Pyruvate kinase deficiency is the second most common cause (after glucose 6-phosphate dehydrogenase deficiency) of enzyme deficiency-related hemolytic anemia.

PRACTICAL LESSON 3

GLUCONEOGENESIS. PENTOSE PHOSPHATE PATHWAY. FRUCTOSE AND GALACTOSE METABOLISM

1. A

2. D

3.C

4.B

5.B

6.B

7.A

8.C

9. E

10. B

QUESTIONS FOR TEST CONTROL MODULE 4

PRACTICAL LESSON 1

LIPIDS: BIOLOGICAL FUNCTIONS AND CLASSIFICATION. METABOLIC PATHWAY OF LIPIDS. DIGESTION AND CATABOLISM

Choose the correct answer:

1. Unsaturated fatty acids are… Choose one incorrect answer.

1. stearic;

2. oleic;

3. linoleic;

4. linolenic;

5. arachidonic.

2. Essential fatty acids are… Choose one correct answer.

1. Stearic acid and oleic acid;

2. Oleic acid and linoleic acid;

3. Linoleic acid and linolenic acid;

4. Linolenic acid and arachidonic acid;

5. Arachidonic acid and stearic acid.

3. Which lipid is very effective surface- active agent and a major constituent of the surfactant preventing adherence?

A. phosphotidylethanolamin (cephalin);

B. phosphotidylserine;

C. dipalmitoyl lecithin;

D. cardiolipin;

E. plasmalogen.

4. Which lipid is a precursor of second messenger?

A. phosphotidylethanolamin (cephalin);

B. phosphotidylserine;

C. phosphotidylinositol;

D. cardiolipin;

E. plasmalogen.

5. Which lipid is a major lipid of mitochondrial membranes?

A. phosphotidylethanolamin (cephalin);

B. phosphotidylserine;

C. phosphotidylinositol;

D. cardiolipin;

E. plasmalogen.

6. Which lipid is found in the nervous system?

A. phosphotidylethanolamin (cephalin);

B. phosphotidylserine;

C. phosphotidylinositol;

D. cardiolipin;

E. ceramide.

7. Which one of the following statements concerning the iodine number of fat is correct?

A. it is the number of grams of iodine taken up by 100 grams of fat. It is an index of the degree of unsaturation;

B. it is the number of grams of iodine taken up by 50 grams of fat. It is an index of the degree of unsaturation;

C. It is the number of milligrams of potassium hydroxide required to saponity one gram of fat;

D. It is an indication of the molecular weight of the fat;

E. Iodine number of butter is 210-230, coconut oil is 253-262.

8. Which shuttle- system participates for the β-oxidation of fatty acids?

A. malate- aspartate;

B. glycerophosphate;

C. citrate;

D. carnitine acyl transferase;

E. malate- oxaloacetate.

9. Which one of the following statements concerning the β-oxidation of fatty acids is incorrect?

A. this process locates in the cytoplasm;

B. intermediates present as CoA derivatives;

C. enzymes present as independent proteins;

D.2 carbon units split off as acetyl CoA;

E. NAD⁺ and FAD are reduced.

1. Triacylglycerol molecules stored in adipose tissue represent the major reserve of substrate providing energy during a prolonged fast. During such a fast:

1. The stored fatty acids are released from adipose tissue into the plasma as components of the serum lipoprotein particle, VLDL;

2. Free fatty acids are produced at a high rate in the plasma by the action of LPL on chylomicrons;

3. Glycerol produced by the degradation of TG is an important direct source of energy for adipocytes and fibroblasts;

4. Hormone-sensitive lipase is phosphorylated by a cyclic AMP- activated protein kinase.