Molecular Biology CSIR Life science MCQs

1). The bases of RNA are the same as those of DNA with the exception that RNA contains
a). cysteine instead of cytosine.
b). uracil instead of thymine.
c). cytosine instead of guanine.
d). uracil instead of adenine.
Answer: b
2). Which one of the following is not a type of RNA?
a). nRNA (nuclear RNA)
b). mRNA (messenger RNA)
c). rRNA (ribosomal RNA)
d). tRNA (transfer RNA)
Answer: a
3). Each amino acid in a protein is specified by
a). several genes.
b). a promoter.
c). an mRNA molecule.
d). a codon.
Answer: d
4). The three-nucleotide codon system can be arranged into ______________ combinations.
a). 16
b). 20
c). 64
d). 128
Answer: c
5). The TATA box in eukaryotes is a
a). core promoter.
b). – 35 sequence.
c). – 10 sequence.
d). 5′ cap.
Answer: a
6). The site where RNA polymerase attaches to the DNA molecule to start the formation of RNA is called a(n)
a). promoter.
b). exon.
c). intron.
d). GC hairpin.
Answer: a
7). When mRNA leaves the cell’s nucleus, it next becomes associated with
a). proteins.
b). a ribosome.
c). tRNA.
d). RNA polymerase.
Answer: b
8). If an mRNA codon reads UAC, its complementary anticodon will be
a). TUC.
b). ATG.
c). AUG.
d). CAG.
Answer: c
9). The nucleotide sequences on DNA that actually have information encoding a sequence of amino acids are
a). introns.
b). exons.
c). UAA.
d). UGA.
Answer: b
10). Which of the following statements is correct about prokaryotic gene expression?
a). Prokaryotic mRNAs must have introns spliced out.
b). Prokaryotic mRNAs are often translated before transcription is complete.
c). Prokaryotic mRNAs contain the transcript of only one gene.
d). All of these statements are correct.
Answer: b