1.
A
drug which prevents uric acid synthesis by inhibiting the enzyme xanthine
oxidase is
A
Aspirin
B.
Allopurinol
D.
Probenecid
C.
Colchicine
2.
A
patient develops severe pain in his big toe. Laboratory tests find elevated
serum uric acid and urate crystals in his urine. The patient's pain is caused
by the overproduction of the end product of which metabolic pathway?
A.
De novo pyrimidine biosynthesis
B.
De novo purine biosynthesis
C.
Pyrimidine degradation
D.
Purine degradation
3.
A
one year old female patient is weak and anemic. Her weight and height are below
average. There are elevated orotic acid levels in her urine. Which compound is
most likely to alleviate the symptoms?
A.
Thymidine
B.
Unidine
C
Hypoxanthine
D.
Guanine
E.
Adenine
4.
Which
of the following is NOT a useful chemotherapeutic agent?
A.
Fluorouracil
B.
Methotrexate
C.
Trimethoprim
D.
Allupurinol
E
Azaserine
5.
NOT
an enzyme involved in purine degradation
A.
Xanthine oxidase
B.
Guanine deaminase
C.
Aminotransferase
D.
Adenosine deaminase
6.
Which
of these is NOT involved in thymidylate synthesis?
A.
Xanthine oxidase
C.
Thymidylate synthase
B.
Dihydrofolate reductase
D.
DUMP E N5N10-methylene THE
7.
Which
enzyme is used to convert GMP into GDP"
A
Thioredoxin kinase
B
Adenylate kinase
C.
Guanylate kinase
D.
NTP kinase
8.
NOT
an enzyme involved in nucleotide salvage
A
Phosphorylases
B
nucleotidases
C.
Nucleoside kinases
D.
Phosphoribosyl oxidase
9.
After
several weeks of methotrexate chemotherapy, a patient's tumour begins to show
signs of resistance to treatment. Which of the following is likely to explain
this?
A.
Overproduction of dihydrofolate reductase
B.
Overproduction of xanthine oxidase
C.
Deficiency of PRPP synthase
D.
Deficiency of thymidine kinase
E.
Deficiency of thymidylate synthase
10.
Orotic
aciduria results from deficiency of 2 enzymes which convert orotate to UMP. One
of these enzymes acts as a:
A
Decarboxylase
B.
Dehydrogenase
C.
Transcarbamoylase
D
Phosphatase
11.
A
patient develops severe pain in his big toe. Laboratory tests find elevated
serum uric acid and urate crystals in his urine. The patient's pain is caused
by the overproduction of the end product of which metabolic pathway?
A.
De novo pyrimidine biosynthesis
C.
Pyrimidine degradation
B.
De novo purine biosynthesis
D.
Purine degradation
12.
A
one year old female patient is weak and anemic. Her weight and height are below
average. There are elevated orotic acid levels in her urine. Which compound is
most likely to alleviate the symptoms?
A.
Thymidine
B.
Unidine
C
Hypoxanthine
D.
Guanine
E.
Adenine
13.
Which
of the following is NOT a useful chemotherapeutic agent?
A.
Fluorouracil
B.
Methotrexate
C.
Trimethoprim
D.
Allupurinol
E
Azaserine
14.
NOT
an enzyme involved in purine degradation
A.
Xanthine oxidase
B.
Guanine deaminase
C.
Aminotransferase
D.
Adenosine deaminase
15.
Which
of these is NOT involved in thymidylate synthesis?
A.
Xanthine oxidase
C.
Thymidylate synthase
B.
Dihydrofolate reductase
D.
DUMP E N5N10-methylene
16.
Which
enzyme is used to convert GMP into GDP
A
Thioredoxin kinase
B
Adenylate kinase
C.
Guanylate kinase
D.
NTP kinase
17.
NOT
an enzyme involved in nucleotide salvage
A
Phosphorylases
B
nucleotidases
C.
Nucleoside kinases
D.
Phosphoribosyl oxidase
18.
After
several weeks of methotrexate chemotherapy, a patient's tumour begins to show
signs of resistance to treatment. Which of the following is likely to explain
this?
A.
Overproduction of dihydrofolate reductase
B.
Overproduction of xanthine oxidase
C.
Deficiency of PRPP synthase
D.
Deficiency of thymidine kinase
E.
Deficiency of thymidylate synthase
19.
Orotic
aciduria results from deficiency of 2 enzymes which convert orotate to UMP. One
of these enzymes acts as a:
A
Decarboxylase
B.
Dehydrogenase
C.
Transcarbamoylase
D
Phosphatase
20.
The
mutation that causes Xeroderma Pigmentosum affects
A.
The primase gene
B.
Nucleotide excision repair
C.
Mismatch repair components
D.
Synthesis DNA across the damaged region
21.
IMP
is
A. A
product of pyrimidine degradation
B.
Precursor to urea
C.
An intermediate in purine synthesis which has only I ring of the purine nucleus
D. A
precursor to AMP and GMP
E
The product of PRPP and glutamine
22.
NOT
an enzyme involved in purine biosynthesis
A Orotate
phosphoribosy transferase
B.
IMP dehydrogeanse
C
Glutamine PRPP amidotransferase
D.
IMP synthase
E
GAR synthetase
23.
NOT
a method of de novo purine synthesis regulation
B.
Inhibition of adeny losuccinate synthetase by GMP
A.
Inhibition of IMP dehydrogenase by GMP
C.
Inhibition of glutamine PRPP amidotransferase by IMP. GMP and AMP
D.
Inhibition of PRPP synthetase by IMP, GMP and AMP
24.
Reaction
involved in de novo synthesis of pyrimidines
A.
Addition of a ribose 5-phosphate side chain from ribulose 5-phosphate
B.
Phosphorylation of uridylate (UMP) to UTP
C.
Phosphorylation of eytidylate (CMP) to CTP
D
Formation of CTP from UTP using aspartate
25.
Source
of carbon atoms in the pyrimidine ring
A.
Alanine
B.
Glycine
C.Phenylalanine
D
glutamate
E
aspartate
26.
Source of carbon atoms in the purine ring
A.
N10-formy tetrahydro folate
B.glycine
C.
asparagine
D
aspartate
E.
glutamate
27.
Statin
drugs are competitive inhibitors of HMG-CoA reductase, to which of the
following?
A)
Mevalonate
B)
Isopentenyl pyrophosphate
C)
Geranyl pyrophosphate
D)
Cholesterol
28.
High
serum HDL levels are protective against the development of atherosclerosis
because
HDL
does which of the following?
A)
Inhibits cholesterol production by the liver
B)
Inhibits HMG-CoA reductase
C)
Brings cholesterol esters back to the liver
D)
Increases LDL production
29.
The
integration of energy metabolism is controlled primarily by :
A)
Epinephrine and norepinephrine
B)
insulin and glucagon
C)
Insulin and Catecholamine's
D)
All are answers
30.
Which
one of the following hormone play a supporting role in the integration of
energy metabolism?
A)
Catecholamine's
B)
Insulin
C)
Glucocorticoids
31.
One
of the following statement is NOT true about Insulin?
A)
Contains an intramolecular disulfide bridge between amino acid residues of the
B-chain
B)
Metabolic effects are anabolic
C)
Enhances glycolysis process
D)
Composed of 51 amino acids
E)
None of the above