RNA Structure

Q1: A nicked RNA molecule can be ligated by

A T4 RNA ligase

B DNA polymerase

C T4 DNA ligase

D all of these

ANS:C - T4 DNA ligase

Catalyzes the formation of a phosphodiester bond between juxtaposed 5' phosphate and 3' hydroxyl termini in duplex DNA or RNA. This enzyme will join blunt end and cohesive end termini as well as repair single stranded nicks in duplex DNA and some DNA/RNA hybrids.

Q2: Retroviruses replicate via __________ intermediate

A RNA

B DNA

C mRNA

D rDNA

ANS:B - DNA

No answer description is available.

Q3: What modified base is at the 5' extremity of a capped eukaryotic m-RNA?

A 1-methyl-adenosine

B 2'-O-methyl-guanosine

C 7-methyl-guanosine

D 1-methyl-guanosine

ANS:C - 7-methyl-guanosine

No answer description is available.

Q4: What is the average size (in bp) of a mature t-RNA?

A 80 bp

B 100 bp

C 120 bp

D 140 bp

ANS:A - 80 bp

No answer description is available.

Q5: Two features of the tRNA molecule associated, in converting the triplet codon to an amino acid, are

A in the T Loop and D stem and loop

B in the anticodon loop and D stem loop

C in the anticodon loop and the 3' CCA end

D none of the above

ANS:C - in the anticodon loop and the 3' CCA end

No answer description is available.

Q6: The mRNA from which of the following would contain a poly-A tail?

A A restriction endonuclease from E. coli

B Bacterial alpha-amylase

C Human insulin

D Bacteriophage DNA ligase

ANS:C - Human insulin

Why insulin would have a poly-A tail?

Q7: The anticodon is a structure on

A mRNA.

B tRNA.

C aribosome.

D rRNA.

ANS:B - tRNA.

No answer description is available.

Q8: In RNA, uracil pairs with

A adenine

B cytosine

C thymine

D guanine

ANS:A - adenine

No answer description is available.

Q9: Which of following RNA characteristically contains unusual purines and pyrimidmes?

A rRNA

B nRNA

C mRNA

D tRNA

ANS:D - tRNA

No answer description is available.

Q10: The genetic material of retroviruses such as HIV is

A DNA

B RNA

C protein

D all of these

ANS:B - RNA

No answer description is available.

Q11: Which of the following is the smallest of the RNAs?

A Messenger RNA

B Transfer RNAs

C Ribosomal RNAs

D All of these

ANS:B - Transfer RNAs

No answer description is available.

Q12: The tertiary structure of yeast tRNA

A involves extensive base stacking interactions

B resembles the 3-dimensional structure of other tRNAs

C is maintained mostly by non-Watson-Crick base pairing

D all of the above

ANS:D - all of the above

No answer description is available.

Q13: During RNA synthesis, the DNA template sequence 5'Tp Ap Gp Cp 3' Would be transcribed to produce which of the following RNA sequence?

A 5'-Ap Tp Cp Gp-3'

B 5'-Gp Cp Up Ap-3'

C 5'-Gp Cp Tp Ap-3'

D 5'-Ap Up Cp Gp-3'

ANS:B - 5'-Gp Cp Up Ap-3'

Yes, B is the answer. The process of RNA synthesis is from 3'to 5' and T (Thymine) is replaced by you (Uracil).

Q14: RNA instability in alkaline solutions is due to

A adenine

B ribose

C uracil

D single strand nature

ANS:B - ribose

No answer description is available.

Q15: What is the function of messenger RNA?

A It carries amino acids

B It is a component of the ribosomes

C It is a direct copy of a gene

D It is the genetic material of some organisms

ANS:C - It is a direct copy of a gene

No answer description is available.



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