44 .An eukaryotic cell, post transcription prepares itself for
synthesis of proteins, so as to meet its metabolic needs.
The modified mRNA translates into proteins through a
sequential stepwise process. Identify the correct
sequence of steps in translation and select the correct
option.
I.Amino acylation of tRNA.
II.Attachment of larger subunit of ribosome to mRNA-
tRNA met complex.
III.Linking of adjacent amino acids to form a
polypeptide.
IV.Codon anticodon reaction between RNA and
amino acyl tRNA complex.
V.Attachment of mRNA with smaller subunit of
ribosome.
(a) I → II → V → IV → III (b) III → II → I → IV → V
(c) I → V → IV → II → III (d) II → IV → V → I → III
45 .Which triplet codon does not have a tRNA associated
with it? [Kerala CEE 2014]
(a) UAA (b) UUA (c) UUU (d) AUU
46. 3 ′-AAA TGC GCG ATA- 5 ′ is the sequence of
nucleotides on a gene, after transcription the mRNA
formed against it and the sequence of bases in the
corresponding binding anticodon will be [AIIMS 2014]
(a) 5 ′-UAU-GUT-CCA-UUU- 3 ′ and 3 ′ AUA-CAU-GGU-AAA- 5 ′
(b) 5 ′-UUU-ACG-CGC-UAC- 3 ′ and 3 ′ AAA-UGC-GCG-AUA- 5 ′
(c) 5 ′-UAU-CGC-GCA-UUU- 3 ′ and 3 ′ AUA-GCG-CGU-AAA- 5 ′
(d) 5 ′-UUU-ACC-TUG-UAU- 3 ′ and 3 ′ AAA-UGG-UAC-AUA- 5 ′
47 .Which one of the following statement is not correct
during protein synthesis? [KCET 2013]
(a) UAA codon codes for lysine
(b) UGG codon codes for tryptophan
(c) Cysteine is coded by UGU and UAC codons
(d) Tyrosine is coded by UAU and UAC codons
48 .Gene of bacteria and virus code for more than one
polypeptide are called [OJEE 2011]
(a) overlapping gene (b) monocistronic gene
(c) polycistronic gene (d) non-ambiguous gene
49 .The reaction [DUMT 2011]
Amino acid + ATP → Aminoacyl AMP + P-P depicts
(a) amino acid assimilation (b) amino acid transformation
(c) amino acid activation (d) amino acid translocation
50 .The one aspect which is not a salient feature of genetic
code, is its being [CBSE AIPMET 2010]
(a) degenerate (b) ambiguous(c) universal (d) specific
51 .Match the following columns.
Column I Column II
A. tRNA 1.Linking of amino acids
B. mRNA 2.Transfer of genetic information
C. rRNA 3.Nucleolar organising region
D. PeptidyI transferase 4.Transfer of amino acid from
cytoplasm to ribosome
Codes
A B C D A B C D
(a) 4 2 3 1 (b) 1 4 3 2
(c) 1 2 3 4 (d) 1 3 2 452 .What would happen if in a gene encoding a
polypeptide of 50 amino acids 25th (UAC) is mutated to
UAA? [AIIMS 2007]
(a) A polypeptide of 49 amino acids will be formed
(b) A polypeptide of 25 amino acids will be formed
(c) A polypeptide of 24 amino acids will be formed
(d) Two polypeptides of 24 and 25 amino acids will be formed
53 .The wild type E. coli cells are growing in normal
medium with glucose. They are transferred to a
medium containing only lactose as sugar. Which of the
following changes take place?
(a) E. coli cells stop dividing (b) The lac operon is induced
(c) The lac operon is repressed (d) All operons are induced
54 .Identify the terms for the following given statements
and select the correct option.
I.A nucleotide sequence that enables a gene to be
transcribed.
II.These gene control the operator gene.
III.A segment of DNA that a repressor binds to.
IV.Genes that are coregulated by operon.
(a)I–Operator II–Structural gene
III–Regulator IV–Promoter
(b)I–Promoter II–Operator
III–Structural gene IV–Regulator
(c)I–Promoter II– Regulator
III-Operator IV–Structural genes
(d)I–Regulator II–Promoter
III–Structural gene IV–Operator
55 .In lac operon, if mutation occurs in the middle gene of
the ‘structural gene’ then [Guj. CET 2014]
(a) β-galactosidase will not be synthesised
(b) permease will not be synthesised
(c) transacetylase will not be synthesised
(d) lactose digestion will be rapid
56 .Select the two correct statements out of the four (I-IV)
given below about lac operon. [CBSE AIPMT 2011]
I.Glucose or galactose may bind with the repressor
and inactivate it.
II.In the absence of lactose the repressor binds with
the operator region.
III.The z-gene code for permease.
IV.This was elucidated by Francisco Jacob and
Jacques Monod.
Which of the following statements given above are
correct?
(a) II and III (b) I and III (c) II and IV (d) I and II
57 .Which of the following events would occur in
lac-operon of E.coli when the growth medium has high
concentration of lactose? [KCET 2014]
(a)The structural genes fail to produce polycistronic mRNA
(b)The repressor protein binds to RNA polymerase and
prevents translation
(c)The repressor protein attaches to the promoter sequence
and represses the operator
(d)The inducer molecule binds to repressor protein and RNA
polymerase binds to promoter sequence