MULTIPLE CHOICE
QUESTIONS FOR M.SC. MICROBIOLOGY ENTRANCE EXAM PREPARATION, TU, 2012
(SUBJECT: MOLECULAR
BIOLOGY/GENETICS)
1. The scientists who proposed 3D model of DNA
a.
Rosaline Frankline
b.
James Watson
c.
Francis crick
d.
Frederick Sanger
2.
Who first discovered Nucleic acid?
a.
Friedrich Miescher
b.
P. A.
Levene
c.
Erwin
Chargaff
d.
Tatum
3. One complete turn of DNA molecules
have ………………..base pairing with …………………diameter.
a.
10 base pairing and 10 nm
b.
12 base pairing and 6 nm
c.
10 base pairing and 34 nm
d.
One base pairing and 3.4 nm
4. Which of the following forces
stabilize the DNA double helix structure?
a.
Hydrogen bonds between complementary bases
b.
Stacking interactions between bases
c.
Super-coiling structure
d.
All
5. Which of the following best
describes the arrangement of the sides of the DNA molecule?
a.
twisted
b.
antiparallel
c.
super coiling
d.
alternating
6. If a DNA
molecule is found to be composed of 40% thymine, what percentage of guanine
would be expected.
a.
10%
b.
20%
c.
40%
d.
80%
7. The enzymes that break hydrogen bonds and
unwind DNA are:
a.
primers
b.
forks
c.
helicases
d.
polymerases
8. Okasaki fragments occur during……………… on
………………………strand.
a.
Transformation and ss RNA
b.
Replication and lagging
c.
polymerase reaction and amplifying DNA
d.
Synthesis and leading
9. Which of the following must happen first in
order for DNA replication to occur?
a.
DNA polymerase binds to the leading strand
b.
DNA is unwound
c.
Hydrogen bonds form between bases
d.
chromosomes condense
10. Which of the following is required for DNA
replication to occur?
a.
DNA helicase
b.
DNA ligase
c.
DNA polymerase
d.
all of these
11. DNA replication results in:
a.
2 completely new DNA molecules
b.
2 DNA molecules that each contain a strand of
the original
c.
1 new DNA molecule, 1 old molecule is
conserved
d.
1 new molecule of RNA
12. During replication, what enzyme adds
complimentary bases?
a.
helicase
b.
synthesase
c.
replicase
d.
polymerase
13. Which one polymerase synthesize DNA
molecule in Replication?
a.
Polymerase I
b.
Polymerase II
c.
Polymerase III
d.
All
14. Which one of the following choices
best completes about the histones:
a.
Are basic proteins rich in lysine and or
arginine
b.
Are bound covalently attached to DNA
c.
Are found in high concentration in ribosomes
d.
Are identical to protamines
15. One class of RNA
characteristically contains unusual purines and pyridines is
a.
tRNA
b.
mRNA
c.
rRNA
d.
16S RNA
16. Which of the following statements
about mRNA is, are correct?
a.
mRNA exists as single stranded molecule.
b.
mRNA has a 7’-methylguanosine “cap” at its 5’
end.
c.
mRNA has a 3’-poly-A sequence.
d.
All of the above
17. Which one of the following choices
best completes about tRNA?
a.
Is the largest of the RNA species
b.
Has little or no secondary structure
c.
Must exist in at least 20 different forms, one
for each amino acid
d.
Exists in cytosol associated with histones
18. Which one of the following
molecule is not a component of the 30S initiation complex?
a.
GTP
b.
Initiation factor 2 (IF2)
c.
mRNA
d.
ATP
19. The genetic code
a.
Is degenerate in that many triplets code for
more than one amino acid
b.
Is read in the direction 3’-5’
c.
Triplet CCA is found at the beginning of
nearly all mRNA coding
d.
Is generally referred to as universal
20. Which one of the following plasmid
codes for the production of bacteriocins ?
a.
F plasmid
b.
R plasmid
c.
Col-plasmid
d.
Virulence plasmid
21. The plaque forming lamda virus is
a.
A lytic virus
b.
A lysogenic virus
c.
A template virus
d.
None
22. The mechanism of tetracycline is
to inhibit translation process by
a.
Blocking the binding of aminoacyl tRNA to
A-site of ribosome
b.
Blocking initiation of RNA chains by binding
to RNA polymerase
c.
Binding DNA to block the movement of RNA polymerase
d.
Preventing the transition from initiation
complex to chain elongating ribosome/miscoding
23. One of the following statement
best describes about the Hfr positive cell in conjugation.
a.
It is a recipient cell
b.
It is a fertile as a chromosomal segment of it
is transferred to F- cell
c.
It has high frequency of recombination
d.
All
24. Short RNA primers required for DNA
replication is synthesized by
a.
DNA primase
b.
DNA ligase
c.
DNA helicase
d.
DNA gyrase
25. Transcription results in:
a.
an amino acid chain
b.
messenger RNA
c.
complementary DNA
d. okazaki fragments
26. A stretch of chromosome that codes for a
trait can be called a(n):
a.
chromatid
b.
replication fork
c.
gene
d.
base-pair
27. In RNA, _____ codon(s) translate to ______
amino acid(s)
a.
1, 1
b.
3, 1
c.
3, 3
d.
1, 20
28. Translation begins:
a.
at the
replication fork
b.
on the lagging strand
c.
at the start codon
d.
in the nucleus
29. A nucleotide consists of:
a.
a phosphate and a base
b.
a phosphate, and a sugar
c.
a base and an amino acid
d.
a phosphate, a sugar, and a base
30. The sugar in RNA is _____, the
sugar in DNA is _______.
a.
deoxyribose,
ribose
b.
ribose, deoxyribose
c.
ribose, phosphate
d.
ribose, uracil
