I. Start the exam by click the “Start” button
NUCLEIC ACIDS- Part 14
See all quizzes of NUCLEIC ACIDS- Part 14 here:
1 Mutations can be caused by
(A) Ultraviolet radiation
(B) Ionising radiation
(C) Alkylating agents
(D) All of these
2. Mutations can be caused by
(A) Nitrosamine (B) Dimethyl sulphate
(C) Acridine (D) All of these
3. Nitrosamine can deaminate
(A) Cytosine to form uracil
(B) Adenine to form xanthine
(C) Guanine to form hypoxanthine
(D) All of these
4. Exposure of DNA to ultraviolet radiation
can lead to the formation of
(A) Adenine dimers (B) Guanine dimers
(C) Thymine dimers (D) Uracil dimers
5. Damage to DNA caused by ultraviolet
radiation can be repaired by
(A) uvr ABC excinuclease
(B) DNA polymerase I
(C) DNA ligase
(D) All of these
6. Xeroderma pigmentosum results from a
defect in
(A) uvr ABC excinuclease
(B) DNA polymerase I
(C) DNA ligase
(D) All of these
7. All the following statements about
xeroderma pigmentosum are true except
(A) It is a genetic disease
(B) Its inheritance is autosomal dominant
(C) uvr ABC excinuclease is defective in this
disease
(D) It results in multiple skin cancers
8. Substitution of an adenine base by guanine
in DNA is known as
(A) Transposition (B) Transition
(C) Transversion (D) Frameshift mutation
9. Substitution of a thymine base by
adenine in DNA is known as
((A) Transposition (B) Transition
(C) Transversion (D) Frameshift mutation
10. A point mutation results from
(A) Substitution of a base
(B) Insertion of a base
(C) Deletion of a base
(D) All of these
11. Substitution of a base can result in a
(A) Silent mutation (B) Mis-sense mutation
(C) Nonsense mutation (D) All of these
12. A silent mutation is most likely to result from
(A) Substitution of the first base of a codon
(B) Substitution of the third base of a codon
(C) Conversion of a nonsense codon into a sense
codon
(D) Conversion of a sense codon into a nonsense
codon
13. The effect of a mis-sense mutation can be
(A) Acceptable (B) Partially acceptable
(C) Unacceptable (D) All of these
14. Amino acid sequence of the encoded
protein is not changed in
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Both (A) and (B)
(D) None of these
15. Haemoglobin S is an example of a/an
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Unacceptable mis-sense mutation
(D) Partially acceptable mis-sense mutation
16. If the codon UAC on mRNA changes into
UAG as a result of a base substitution in
DNA, it will result in
(A) Silent mutation
(B) Acceptable mis-sense mutation
(C) Nonsense mutation
(D) Frameshift mutation
17. Insertion of a base in a gene can cause
(A) Change in reading frame
(B) Garbled amino acid sequence in the
encoded protein
(C) Premature termination of translation
(D) All of these
18. A frameshift mutation changes the
reading frame because the genetic code
(A) Is degenerate
(B) Is overlapping
(C) Has no punctuations
(D) Is universal
19. Suppressor mutations occur in
(A) Structural genes (B) Promoter regions
(C) Silencer elements (D) Anticodons of tRNA
20. Suppressor tRNAs can neutralize the
effects of mutations in
(A) Structural genes (B) Promoter regions
(C) Enhancer elements (D) All of these
21. Mutations in promoter regions of genes
can cause
(A) Premature termination of translation
(B) Change in reading frame of downstream
structural gene
(C) Decreased efficiency of transcription
(D) All of these
22. Mitochondrial protein synthesis is inhibited
by
(A) Cycloheximide (B) Chloramphenicol
(C) Diptheria toxin (D) None of these
23. All of the following statements about
puromycin are true except
(A) It is an alanyl tRNA analogue
(B) It causes premature termination of protein
synthesis
(C) It inhibits protein synthesis in prokaryotes
(D) It inhibits protein synthesis in eukaryotes
24. Leucine zipper motif is seen in some helical
proteins when leucine residues appear at
every
(A) 3rd position (B) 5th position
(C) 7th position (D) 9th position
25. Zinc finger motif is formed in some
proteins by binding of zinc to
(A) Two cysteine residues
(B) Two histidine residues
(C) Two arginine residues
(D) Two cysteine and two histidine residues or two
pairs of two cysteine residues each
26. Restriction endonucleases are present in
(A) Viruses (B) Bacteria
(C) Eukaryotes (D) All of these
27. Restriction endonucleases split
(A) RNA
(B) Single stranded DNA
(C) Double stranded DNA
(D) DNA-RNA hybrids
28. Restriction endonucleases can recognise
(A) Palindromic sequences
(B) Chimeric DNA
(C) DNA-RNA hybrids
(D) Homopolymer sequences
29. All of the following statements about
restriction endonucleases are true except:
(A) They are present in bacteria
(B) They act on double stranded DNA
(C) They recognize palindromic sequences
(D) They always produce sticky ends
30. Which of the following is a palindromic
sequence
(A)
(B)
′ − − ′
′ − − ′
5 ATGCAG 3
3 TACGTC 5
(C)
(D)
′ − − ′
′ − −
