2005
Q151
NEET
MCQ
10 Mar 2026
E. coli cells with a mustard z gene of the lac
operon cannot grow in medium containing only
lactose as the source of energy because -
A.
They cannot transport lactose from the
medium into the cell
B.
They cannot synthesize functional beta
galactosidase
C.
In the presence of glucose, E. coli cells do
not utilize lactose
D.
The lac operon is constitutively active in
these cells
2004
Q152
NEET
MCQ
10 Mar 2026
In a mutational event, when adenine is replaced
by guanine, it is a case of -
A.
Frameshift mutation
B.
Transition
C.
Transversion
D.
Transcription
2004
Q153
NEET
MCQ
10 Mar 2026
Which form of RNA has a structure resembling
clover leaf ?
A.
r-RNA
B.
m-RNA
C.
t-RNA
D.
hn-RNA
2004
Q154
NEET
MCQ
10 Mar 2026
The following ratio is generally constant for a
given species :-
A.
A + C / T + G
B.
G + C / A+ T
C.
A + G / C +T
D.
T + C / G + A
2004
Q155
NEET
MCQ
10 Mar 2026
After a mutation at a genetic locus the character
of an organism changes due to the change in :-
A.
Protein synthesis pattern
B.
RNA transcription pattern
C.
DNA replication
D.
Protein structure
2004
Q156
NEET
MCQ
10 Mar 2026
During transcription, if the nucleotide sequence
of the DNA strand that is being coded is
ATACG, then the nucleotide sequence in the
mRNA would be -
A.
UAUGC
B.
TCTGG
C.
UATGC
D.
TATGC
2003
Q157
NEET
MCQ
10 Mar 2026
During translation initiation in prokaryotes, a
GTP molecule is needed in : -
A.
Association of 30S mRNA with formy-lmet-tRNA
B.
Formation of formyl-met-tRNA
C.
Association of 50S subunit of ribosome
with initiation complex
D.
Binding of 30S subunit of ribosome with
mRNA
2003
Q158
NEET
MCQ
10 Mar 2026
In the genetic code dictionary, how many
codons are used to code for all the 20 essential
amino acids : -
A.
64
B.
20
C.
60
D.
61
2003
Q159
NEET
MCQ
10 Mar 2026
Degeneration of a genetic code is attributed to
the : -
A.
Second member of a codon
B.
Third member of a codon
C.
First member of a codon
D.
Entire codon
2003
Q160
NEET
MCQ
10 Mar 2026
What does "lac" refer to in what we call the lac
operon ?
A.
The number 1,00,000
B.
Lac insect
C.
Lactase
D.
Lactose
2003
Q161
NEET
MCQ
10 Mar 2026
Which one of the following triplet codes, is
correctly matched with its specificity for an
amino acid in protein synthesis or as 'start' or
'stop' codon ?
A.
UUU – Stop
B.
UAC – Tyrosine
C.
UGU – Leucine
D.
UCG – Start
2003
Q162
NEET
MCQ
10 Mar 2026
What would happen if in a gene encoding a
polypeptide of 50 amino acids, 25th codon
(UAU) is mutated to UAA ?
A.
A polypeptide of 49 amino acids will be
formed
B.
A polypeptide of 25 amino acids will be
formed
C.
Two polypeptides of 24 and 25 amino acids
will be formed
D.
A polypeptide of 24 amino acids will be
formed
2003
Q163
NEET
MCQ
10 Mar 2026
During transcription, the DNA site at which
RNA polymerase binds is called :-
A.
Receptor
B.
Regulator
C.
Enhancer
D.
Promoter
2002
Q164
NEET
MCQ
10 Mar 2026
Transformation experiment was first performed
on which bacteria : -
A.
Diplococcus pneumoniae
B.
Pasteurella pestis
C.
E. coli
D.
Salmonella
2002
Q165
NEET
MCQ
10 Mar 2026
Which of the following reunites the exon
segments after RNA splicing ?
A.
RNA polymerase
B.
RNA proteases
C.
RNA primase
D.
RNA ligase
2002
Q166
NEET
MCQ
10 Mar 2026
Change in sequence of nucleotide in DNA is
called as -
A.
Recombination
B.
Mutation
C.
Mutagen
D.
Translation
2002
Q167
NEET
MCQ
10 Mar 2026
In a DNA percentage of thymine is 20% then
what is the percentage of guanine : -
A.
40%
B.
20%
C.
30%
D.
60%
2002
Q168
NEET
MCQ
10 Mar 2026
Which of the following enzymes are used to join
bits of DNA ?
A.
Endonuclease
B.
DNA polymerase
C.
Ligase
D.
Primase
2002
Q169
NEET
MCQ
10 Mar 2026
Out of 64 codons, 61 codons code for 20 types
of amino acid it is called : -
A.
Wobbling of codon
B.
Universility of codons
C.
Overlapping of gene
D.
Degeneracy of genetic code
2002
Q170
NEET
MCQ
10 Mar 2026
In E. Coli, during lactose metabolism repressor
binds to : -
A.
Promoter gene
B.
Operator gene
C.
Structural gene
D.
Regulator gene
2002
Q171
NEET
MCQ
10 Mar 2026
Exon part of m-RNAs have code for : -
A.
Lipid
B.
Protein
C.
Phospholipid
D.
Carbohydrate
2002
Q172
NEET
MCQ
10 Mar 2026
Jacob and Monad studied lactose metabolism in
E.Coli and proposed operon concept. Operon
concept applicable for :
A.
All prokaryotes and all eukaryotes
B.
All prokaryotes and some protozoanes
C.
All prokaryotes
D.
All prokaryotes and some eukaryotes
2001
Q173
NEET
MCQ
10 Mar 2026
m-RNA is synthesised on DNA template in
which direction : -
A.
Any
B.
Both (c) and (d)
C.
5' → 3'
D.
3' → 5'
2001
Q174
NEET
MCQ
10 Mar 2026
Types of RNA polymerase required in nucleus
for RNA synthesis : -
A.
2
B.
3
C.
1
D.
4
2001
Q175
NEET
MCQ
10 Mar 2026
Gene and cistron words are sometimes used
synonymously because : -
A.
One gene contains one cistron
B.
One cistron contains many gene
C.
One gene contains no cistron
D.
One gene contains many cistrons
2001
Q176
NEET
MCQ
10 Mar 2026
In Negative operon : -
A.
CAMP have negative effect on lac operon
B.
Co-repressor binds with inducer
C.
Co-repressor binds with repressor
D.
Co-repressor does not binds with repressor
2000
Q177
NEET
MCQ
10 Mar 2026
Length of one loop of B- DNA :
A.
20 nm.
B.
10 nm.
C.
3.4 nm.
D.
0.34 nm.
2000
Q178
NEET
MCQ
10 Mar 2026
Method of DNA replication in which two
strands of DNA separates and synthesize new
strands
A.
Conservative
B.
Non conservative
C.
Dispersive
D.
Semiconservative
2000
Q179
NEET
MCQ
10 Mar 2026
In three dimensional view the molecule of
t-RNA is :
A.
E-shaped
B.
L-shaped
C.
S-shaped
D.
Y-shaped
2000
Q180
NEET
MCQ
10 Mar 2026
Which of the following is initiation codon ?
A.
AUC
B.
CCU
C.
UAG
D.
AUG
2000
Q181
NEET
MCQ
10 Mar 2026
Anticodon occurs in :
A.
DNA
B.
r-RNA
C.
t-RNA
D.
m-RNA
2000
Q182
NEET
MCQ
10 Mar 2026
Similarity in DNA and RNA :
A.
Both have similar sugar
B.
Both are genetic material
C.
Both have similar pyrimidine
D.
Both are polymer of nucleotides