Nucleic Acids - Mock Test 23

Question 221

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

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Question 222

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

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Question 223

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

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Question 224

Mitochondrial protein synthesis is inhibited by?

A) Cycloheximide B) Chloramphenicol C) Diptheria toxin D) None of these

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Question 225

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

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Question 226

Suppressor tRNAs can neutralize the effects of mutations in?

A) Structural genes B) Promoter regions C) Enhancer elements D) All of these

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Question 227

Suppressor mutations occur in?

A) Structural genes B) Promoter regions C) Silencer elements D) Anticodons of tRNA

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Question 228

A frameshift mutation changes the reading frame because the genetic code?

A) Is degenerate B) Is overlapping C) Has no punctuations D) Is universa

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Question 229

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

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Question 230

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

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