4. Q1:about the diagram. (5 marks)
Aa:1/galactokinase
2/gala 1 p uridyl transferase
3/ uridyl diphospho galactose 4 epimerase
4/UDP_Glc pyrophos
Ab : it cause galactosemia
Ac:
Q2: describe the process of anaerobic glycolysis and state its function (4 marks)
A2:
5. This occur in muscle during severe exercise (hypoxic conditions) and in tissues that lack
in mitochondria as RBCs and lens.
Q3: compare between ketolysis and ketogenesis. (2 marks)
Q4: discuss the syn of mevalonate and mention its importance. (3 marks)
Its importance : act as a precursor for cholesterol synthysis
Q5: discuss synthysis and fates of ceramide. (4 marks)
ketogenesis ketolysis
organ Liver Non hepatic tissue
Subcellular compartment mitochondria mitochondria
Rate limiting step HMG coA synthase Succenyl coA acetoacetate
coA ransferase
function Formation of keton bodies
in fed state
Utilization of keton bodies
in fasting stae
6. Fates:
1/ formation of cerebroside (galactocerebroside)
2/ sphingomylien
Q6: discuss two different pathways for syn of serine. (3 marks)
7. Q7: illustrate the biochemical reaction needed to the following conversions and mention
one metabolic error for each:
a) Cirtullin : arginine (2 marks )
8. Metabolic error : high arginine level stimulate n_acetyl glutamate synthase enz.
Thus increase urea formation
b) Methionine:cysteine (3 marks )
Metabolic error : homocysinurea
9. Q8:write a short note about transamination. (2marks)
It transfere the amino group from an amino acid to alpha keto acid . all the amino acids
participate in the reaction except therionine and lysine . vit B6 is required as a co_enz.
Most of transamination require alpha keto glutaric and glutamate as one of the reacting
pair. It is cytosolic and mitochondrial enz. It is reversible reaction.
The most important are : AST & ALT
Q9 : illustrate the sites of energy release in the ETC and mention one inhibitor for each
(2 marks)
Coupling site 1 lies between FMN and coQ
Coupling site 2 lies between cytochrome b and c1
Coupling site 3 lies between cytochronme a and a3
Inhibitor of coupling site 1: parpiturate and piericidin A and rotenone
Inhibitor of coupling site 2: antimycin and dimercaprol
Inhibitor of coupling site 3: hydrogen sulphide and carbonmonoxide and cynaide
10. Q10: enumerate types of enz activator and give one example for each. (3 marks)
A10: 1/removal of inhibitory peptie e.g pepsinogen to pepsin
2/ some enz contain SH gp e.g glyceraldehyde 3 p dehydrogenase require reducing
agent to b activated
3/ some enz. Require minerals e.g Mg for kinase
4/allosteric activator e.g AMP of PFK
5/ covelant modification phosphaliration to glycogen synthase
Q11: enumerate function and sign of deficiency of:
A)thiamin (2 marks )
1/oxiditivie decarboxylation of alpha keto acid
2/transketolase reaction
3/TTP if required for acetylcholine synthesis which is one of neurotransmitters
Sign of deficiency: beriberi
B) vitamin A (2 marks )
1/ anticancer agent
2/ cell growth and deffrentiation
3/ health and integrity of epithelial tissue
4/ play a role in vision
Sign of deficiency: night blindness , follicular hyperkeratosis , xerophthalamia ,
keratomalacia.
Q12: define the basal metablic rate and enumerate conditions under which it is
measured. (3 marks )
11. It is a the minimal energy expenditure for the body to exist under basal conditions
Conditions:
1/ complete physical and mental rest (but no sleep)
2/ post absorbitive state 12:14 hours after the last meal
3/ at a comfortable room temperature
Q13: define the oxygen dept and how to calculate it (2 marks )
Is the extra consumbtion of oxygen after completion of severe exercise .
Calculation : oxygen dept = oxygen consumbtion during recovery โ oxygen
consumption during an equal period of rest
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