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In the Meselson and Stahl experiment after two
generations of replication in 14N containing culture media, what was the amount of 14N and 15N in the two bands?
a. None 14N and all 15N
b. All 14N and 15N
c. ¼ 14N and ¾ 15N
d. ½ of14Nand 15N
e. ¾ 14N and ¼ 15N
e. ¾ 14N and ¼ 15N
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The process of re-hybridizing meted DNA is called:
a. Denaturation
b. Tm
c. Annealing
d. Dehybridization
e. Replication
c. Annealing
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In proteins, amino acids are linked by peptide bonds in polynucleotide (DNA,RNA) nucleotides are linked by:
a. Phophoanhydride bond
b. 3’ – 5’ phosphodiester bonds
c. 5’- 3’ phophodiester bonds
d. B and C
e. All of the above
b. 3’ – 5’ phosphodiester bonds
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The tetranucleotide AGTC (in DNA) has a free hydroxyl group on:
a. A
b. AGT and C
c. C
d. GT and C
c. C
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In a double stranded DNA, if the total thymine
(T) content is 20%. What percent of Guanine (G) is present in the same double strand of DNA?
a. 30%
b. 40%
c. 60%
d. 80%
a. 30%
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The “Okazaki fragments” synthesized during the
leading strand replication are processed by DNA polymerase and DNA ligase to give a rise to a continuous strand of DNA.
a. True
b. False
b. False
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DNA polymerase needs a primer to replicate DNA.
The primer is an RNA molecule formed by the enzyme _________
Primase
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The enzyme photolyase functions to:
a. Repair pyrimidine dimers
b. Remove damaged bases
c. Repair single strand breaks
d. Remove mismatched base pairs
e. None of the above
a. Repair pyrimidine dimers
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Deaminated bases must be removed from DNA because
a. They are very sticky
b. They form thymine dimers
c. They pair incorrectly during replication
d. The mRNA formed may be irregular
c. They pair incorrectly during replication
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In DNA repair, DNA glycosylases recognize
deaminated bases within the DNA polymer and remove the deaminated
a. Nucleoside
b. Nucleotide
c. Thymine dimers
d. Bases
e. Sugar
d. Bases
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During transcription the antisense DNA strand is
used as a template for mRNA synthesis. If the sequence of the sense strand DNA is 5’ ATGGGCACTA 3‘, which of the following would be the sequence of the mRNA?
a. 5’AUGGCACUA3’
b. 3’AUGGCACUA5’
c. 5’ATGGCACTA3’
d. 5’UAGUGCCAU3’
a. 5’AUGGCACUA3’
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Which of the following is correct?
a. Transcription proceeds in the 5’ à 3’ direction
b. The template strand is copied from the 5’ end to the 3’ end
c. RNA polymerization proceeds in the 3’ à5’ direction
d. DNA polymerization proceeds in the 3’ à 5’ direction
e. None of the above are correct
a. Transcription proceeds in the 5’ à 3’ direction
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Which of the following is TRUE, concerning rho
protein?
a. It is a homomultimeric protein without ATPase
activity
b. It has an affinity for single stranded DNA
c. It has an affinity for single stranded RNA
d. None ofthe above
c. It has an affinity for single stranded RNA
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The LAC operon is an Inducible Operon this means it is usually __________ and directly controlled by ___________
a. Active/ an inducer
b. Active/ a repressor
c. Inactive/ an inducer
d. Inactive/ an repressor
e. Active/ CAP protein
d. Inactive/ an repressor
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The LAC operon is induced when lactose is present as the only carbon source. The real inducer of the operon in cells ______
Allolactose
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RNA polymerase I transcribes the genes for
a. mRNA precursors
b. 18S, 5.8S and 28S rRNA
c. Most tRNA
d. All of the above
e. None of the above
b. 18S, 5.8S and 28S rRNA
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