Biochemistry Exam For second year students
ثانية (نظام حديث ) Part III
I – Write fully the synthetic pathway of the following compounds: (10 marks)
a – urea .
b – serotonin .
c – porphbilinogen .
d- Mechanism for skeletal muscle to eliminate nitrogen while replenishing
its energy supply.
II – Show by chemical equation the following conversions : (10 marks)
1. Serine a . a to pyruvic acid .
2. Guanido acetate to creatine phosphate .
3. Glycine to glychocholic acid .
4. Cysteine to cystine .
5. Homogentisic acid to maleylacetoacetic acid .
III – Choose the correct answer : (2 ½ marks )
1-Most of the ammonia is derivatized and transported in the blood as ?
(A) glutamate (B) arginine (C) glutamine (D) alanine .
2-An amino acid which is strictly ketogenic will be able to yeild ?
(A) Energy (B) ketone bodies (C) Fatty acids (D) Glucose .
3-Creatinine is formed from the ?
(A) oxidation of protein (B) deamination of dibasic amino acid
(C) oxidation of creatine (D) metabolism of purines .
4-Which enzyme deficiency is responsible for phenylketonuria ( PKU )?
(A) p-hydroxyphenyl pyruvic hydroxylase (B) phenyl alanine hydoxylase
(C) Tyrosine transaminase (D) Homogentisic acid oxidase .
5-The reaction of urine in convertion is ?
(A)Neutral (B) Alkaline (C) Acidic . (D) Basic
IV – Tick (? ) or ( X ) and correct the wrong answers: ( 2 ½ marks )
1. The consistency of urine in equines is watery .
2. Chronic liver diseases cause pathological glycosuria .
3. The odour of freshly voided urine is due to volatile organic acids .
4. Transamination reaction requires Biotin as a co factor .
5. carbamoyl phosphate synthetase I is cytosolic enzyme .
Good Luck Prof.Dr. Ibrahim Fattouh