I. Start the exam by click the “Start” button
NUCLEIC ACIDS- Part 21
See all quizzes of NUCLEIC ACIDS- Part 21 here:
1 In the ’lac operon’ concept, which of the
following is a protein?
(A) Operator (B) Repressor
(C) Inducer (D) Vector
2. Degeneracy of the genetic code denotes
the existence of
(A) Base triplets that do not code for any amino
acids
(B) Codons consisting of only two bases
(C) Codons that include one or more of the
unusual bases
(D) Multiple codons for a single amino acid
3. The normal function of restriction endonucleases
is to
(A) Excise introns from hrRNA
(B) Polymerize nucleotides to form RNA
(C) Remove primer from okazaki fragments
(D) Protect bacteria from foreign DNA
4. In contrast to Eukaryotic mRNA, prokaryotic
mRNA is characterized by
(A) Having 7-methyl guanosine triphosphate at
the 5’ end
(B) Being polycystronic
(C) Being only monocystronic
(D) Being synthesized with introns
5. DNA ligase of E. coli requires which of the
following co-factors?
(A) FAD (B) NAD+
(C) NADP+ (D) NADH
6. Which of the following is transcribed
during repression?
(A) Structural gene (B) Promoter gene
(C) Regulator gene (D) Operator gene
7. mRNA is complementary copy of
(A) 5′-3′ strand of DNA+
(B) 3′-5′ strand of DNA
(C) Antisense strand of DNA
(D) tRNA
8. Synthesis of RNA molecule is terminated
by a signal which is recognised by
(A) α-factor (B) β-factor
(C) δ-factor (D) ρ
9. The binding of prokaryotic DNA dependent
RNA polymerase to promoter sits of
genes is inhibited by the antibiotic:
(A) Streptomycin (B) Rifamcin
(C) Aueromycin (D) Puromycin
10. In E. coli the chain initiating amino acid in
protein synthesis is
(A) N-formyl methionine(B) Methionine
(C) Serine (D) Cysteine
274 MCQs IN BIOCHEMISTRY
11. Amanitin the mushroom poison inhibits
(A) Glycoprotein synthesis
(B) ATP synthesis
(C) DNA synthesis
(D) mRNA synthesis
12. How many high-energy phosphate bond
equivalents are required for amino acid
activation in protein synthesis?
(A) One (B) Two
(C) Three (D) Four
13. Translation results in the formation of
(A) mRNA (B) tRNA
(C) rRNA (D) A protein molecule
14. Elongation of a peptide chain involves all
the following except
(A) mRNA (B) GTP
(C) Formyl-Met-tRNA (D) Tu, TS and G factors
15. The ‘rho’ (ρ) factor is involved
(A) To increase the rate of RNA synthesis
(B) In binding catabolite repressor to the promoter
region
(C) In proper termination of transcription
(D) To allow proper initiation of transcriptide
16. In the biosynthesis of c-DNA, the joining
enzyme ligase requires
(A) GTP (B) ATP
(C) CTP (D) UTP
17. Which one of the following binds to
specific nucleotide sequences that are
upstream and most distant from the start
site?
(A) RNA polymerase (B) Repressor
(C) Inducer (D) Restriction
18. Using written convention which one of the
following sequences is complimentary to
TGGCAGCCT?
(A) ACCGTCGGA (B) ACCGUCGGA
(C) AGGCTGCCA (D) TGGCTCGGA
19. Ribosomes similar to those of bacteria
found in
(A) Plant nuclei
(B) Cardiac muscle cytoplasm
(C) Liver endoplasmic reticulum
(D) Neuronal cytoplasm
20. The mechanism of synthesis of DNA and
RNA are similar to all the following ways
except
(A) They involve release of pyrophosphate from
each nucleotide added
(B) They require activated nucleotide precursor
and Mg2+
(C) The direction of synthesis is
(D) They require a primer
21. Template-directed DNA synthesis occurs in
all the following except
(A) The replication fork
(B) Polymerase chain reaction
(C) Growth of RNA tumor viruses
(D) Expression of oncogenes
