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WorksheetsBiochemistry - Tutorial (Nucleotide metabolism)
Total questions: 17
Worksheet time: 13mins
Name
Class
Date
1.
The two purine nucleotides found in RNA are:
a)
formed in a branched pathway from a common intermediate
b)
formed in a sequential pathway
c)
derived from exogenous sources
d)
formed by oxidation of NADH
2.
Uric acid is
a)
synthesised from xanthine in the presence of O2
b)
a degraded product of cytidine
c)
deficient in the condition known as gout
d)
a competitive inhibitor of xanthine oxidoreductase
3.
Which of the following descriptions regarding nucleotide catabolism is INCORRECT?
a)
Nucleotidases degrade nucleotides to nucleosides.
b)
AMP is degraded to the free base hypoxanthine.
c)
Xanthine is the common product for AMP and GMP catabolism.
d)
Catabolism of UTP leads to the formation of uric acid.
4.
Which of the following descriptions regarding deoxyribonucleotides is CORRECT?
a)
They are essential amino acids.
b)
They are synthesised de novo without PRPP.
c)
They are synthesised from ribonucleotides by an enzyme system involving thioredoxin.
d)
They are synthesised by nucleotide kinases.
5.
Nucleotides required for the synthesis of nucleic acids can be obtained from ___________.
a)
Hydrolysis of peptide bonds.
b)
de novo pathway only.
c)
salvage pathway only.
d)
De novo and salvage pathway.
6.
For de novo synthesis of purine nucleotides, glycine provides __________________.
a)
one nitrogen atom
b)
one nitrogen and one carbon atom
c)
two carbon atoms
d)
one nitrogen and two carbon atoms
7.
5-Phosphoribosyl-1-pyrophosphate (PRPP) is required for the synthesis of ____________________.
a)
purine nucleotides only
b)
pyrimidine nucleotides only
c)
purine and pyrimidine nucleotides
d)
None of the above
8.
Inosine monophosphate (IMP) is an intermediate during de novo synthesis of ________________.
a)
AMP and GMP
b)
CMP and UMP
c)
CMP and TMP
d)
All of the above
9.
Describe TWO (2) differences between purine and pyrimidine synthesis.
4 lines
10.
Name ONE (1) important compound/molecule in regulating the de novo synthesis of guanosine monophosphate?
4 lines
11.
Name the enzyme which catalyses the transfer of free guanine to GMP?
4 lines
12.
Name one disorder related to this enzyme.
4 lines
13.
Describe ONE (1) difference between a deoxyribonucleotide and a ribonucleotide.
14.
Name the enzyme that catalyses the reduction of a ribonucleotide.
4 lines
15.
Name the branching molecule during de novo synthesis of AMP and GMP.
16.
Briefly explain the role of xanthine oxidase inhibitors in the treatment of gout.
4 lines
17.
Why is dATP toxic to mammalian cells? (Hint: ribonucleotide reductase)
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