Download MBBS (Bachelor of Medicine and Bachelor of Surgery) UHS Lahore (University of Health Sciences Lahore) 1st Year Biochemistry II SEQ Previous Year Question Paper
MBBS FIRST PROFESSIONAL (PART-II)
MODEL PAPER FOR ANNUAL 2009
Biochemistry
(Short Essay Questions)
Max. Marks 32.5 Time Allowed 2 hours
1. a) Draw and label a diagram to illustrate the components,
organization and site specific inhibitors of electron transport chain.
2
b) How is 5?phosphoribosyl-1-pyrophosphate (PRPP) synthesized?
Name the amino acid which takes part in purine ring formation.
1.5,0.5
2. a) What are the biochemical events involved in the causation of
cataract in uncontrolled diabetes mellitus?
2
b) How creatine phosphate is synthesized? Calculate energy yield in
the form of mole of ATP from one mole of palmitate.
1+1
3. a) What are the enzyme deficiencies in essential fructosuria and
hereditary fructose intolerance? Write down the reactions catalyzed
by these enzymes. Which one of these two conditions leads to
severe hypoglycemia after fructose ingestion and why? What is the
cause of hyperuricemia in this condition?
3
b) What is the role of glucose 6-phosphate dehydrogenase in red
blood cells?
1
4. a) A 19 year old girl was referred to a University Medical Centre
because of easy fatigability and poor exercise tolerance in her
extremities. Several muscle biopsy were performed. Microscopic
examination indicated that muscle was filled with vacuoles
containing lipid. Chemical measurements indicated that these
muscles specimen contained greatly elevated amount of
triglycerides but only one sixth as much carnitine as biopsy
specimen obtained from other patient who did not have any
primary muscle disease.
i) What is main intracellular function of carnitine?
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ii) Would you expect that the fatty acid -oxidation is impaired in
this patient?
0.5
b) Write down complete reaction for synthesis and utilization of ketone
bodies?
2.5
5. Explain the biochemical basis of phenyl ketonuria, alkaptonuria and
maple syrup urine disease. Mention the nutritional strategy to be
adopted for treatment of phenyl ketouria?
3+1
6. a) A 32 year old male presents to ENT clinic with complaints of a sore
throat. He reports numerous upper respiratory tract infections over
the last three months. Patient gives a history of intravenous drug
use in the past, but no other significant medical history is given. On
examination, patient is found to have a temperature of 37.8?C
(100.0?F) and is in minimal distress from the sore throat. His
pharynx is erythematous and has numerous white plaques coating
the throat.
There is also prominent cervical lymph node enlargement. His chest
is clear to auscultation and heart is with regular rate and rhythm. A
CD4 T-lymphocyte cell count is performed and is less than 200 cells
per mm3 (normal > 500).
He was diagnosed as a case of secondary infection to HIV infection.
0.5
i) HIV is abbreviation of which pathogen?
ii) Which enzyme is required for this pathogen to affect the host
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genome?
iii) What is the biochemical mechanism that the pathogen uses to
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affect the patient cells?
b) For each of the following steps in prokaryotic protein synthesis
(1 to 4) indicate the most appropriate antibiotic (A-J) to inhibit the
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process.
i) Transfer of the peptide from the pepitidyl-tRNA to the amino
acyl-tRNA and formation of a peptide bond.
ii) Binding of amino acyl-tRNA from the A-site of the ribosomal
complex.
iii) Translocation of the peptidyl-tRNA from the A-site to the P-site.
iv) Interference with the initiation of protein synthesis.
a) Amino glycosides f) Lincosamides
b) Chloramphenicol g) Neomycin
c) Erythromycin h) Puromycin
d) Gentamicin i) Streptomycin
e) Kanamycin j) Tetracycline
7. a) A baby aged 2 months, was admitted with 2 week history of
vomiting and septicemia. On admission he was severely dehydrated
and had circulatory collapse. Following investigations were
performed.
Normal range
?
Na 132 mEq/L (135-145)
?
K 2.6 mEq/L (3.5-5)
?
Cl 72 mEq/L (93-108)
?
HCO3 41.4 mEq/L (22-26)
?
pH 7.77 ( 7.35-7.45)
?
pCO2 36 mmHg (35-45)
i) What is your diagnosis?
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ii) Is there any compensation?
0.5
iii) How does change in blood pH influence distribution of
potassium and chloride ions in intracellular and extracellular
fluid?
1
b)
What is the significance of dietary fiber? Find out the caloric
requirement / day of a 10 year old school boy who is moderately
active and his BMR is 400 KCal (energy expenditure for moderate
physical activity is 5 times that of BMR).
2
8. What are the steps for synthesis and secretion of thyroxin?
4.5
This post was last modified on 04 December 2021