III.Okazaki fragments form the continuous strand.
IV.Leading strand is synthesised in 5 ′→ 3 ′ direction.
(a) I, II and IV (b) Only II
(c) II and IV (d) I, II, III and IV
16 .Which option shows correctly labelled region in the
given diagram of DNA replication? [Guj CET 2014]
(a) A and C (b) Only C (c) A and B (d) B and C
17 .Choose the correct statement. [Kerala CEE 2014]
(a)Haploid content of human DNA is 4.6 × 106 bp
(b)A nitrogenous base is linked to pentose sugar through
phosphodiester linkage
(c)X-ray diffraction data of Maurice Wilkins and Rosalind
Franklin was the basis of Watson and Crick's DNA model
(d)DNA, an acidic substance was first identified by Watson
and Crick18 .Identify the wrong statement about DNA.
[Kerala CEE 2014]
(a)The length of DNA is defined as the number of base pairs
present in it
(b)Cytosine is common to both DNA and RNA
(c)In a nucleotide, the nitrogenous base is linked to
phosphate group.
(d)Deoxythymidine is a nucleoside
19 .When the DNA replication starts the [AIIMS 2012]
(a)leading strand produces Okazaki fragment
(b)hydrogen bonds between the nucleotides of two strands
break
(c)phosphodiester bond between the adjacent nucleotides
break
(d)bonds between the nitrogen base and deoxyribose sugar
break
20 .In prokaryotes, the process of replication is catalysed
by the following enzymes. Identify, which of the
enzymes best coordinate with the role [AIIMS 2013]
(a) Helicase—Joins the ends of DNA segments
(b) DNA polymerase-I—Synthesises DNA
(c) DNA polymerase-II—Erases primer and fills gaps
(d) Primase—Synthesises RNA primers
21 .Given below is a sample of portion of DNA strand
giving the base sequence on the opposite strands.
What is so special shown in it? [CBSE AIPMT 2011]
5 ′—GAATTC— 3 , ′ 3 ′—CTTAAG— 5 ′
(a) Deletion mutation
(b) Start codon at the (^5) ′ end
(c) Palindromic sequence of base pairs
(d) Replication completed
22 .The number of base pairs per helical turn in Z-DNA is
(a) 10 (b) 11
(c) 12 (d) 13
23 .Out of A–T, G–C pairing, bases of DNA may exist in
alternate valency state owing to a arrangement called
[WB JEE 2009]
(a) tautomerisational mutation(b) analogue substitution
(c) point mutation (d) frameshift mutation
24 .An analysis of a DNA (double stranded) sample
yielded 18% cytosine. What would be the percentage of
other bases in the sample? [Haryana PMT 2009]
(a) T–32%, A–32%, G–18% (b) T–32%, A–18%, G–32%
(c) T–18%, A–32%, G–32% (d) T–40%, A–22%, G–20%
25 .Which one of the following pairs of nitrogenous base of
nucleic acids, is wrongly matched with the category
mentioned against it? [CBSE AIPMT 2008]
(a) Thymine, uracil — Pyrimidines
(b) Uracil, cytosine — Pyrimidines
(c) Guanine, adenine — Purines
(d) Adenine, thymine — Purines
26 .During replication of a bacterial chromosome, DNA
synthesis starts from a replication origin site and
[Manipal 2007]
(a) RNA primers are involved
(b) is facilitated by telomerase
(c) moves in one direction of the site
(d) moves in bi-directional way
27 .E.Coli about to replicate was placed in a medium
containing radioactive thymidine for 5 minutes. Then
it was made to replicate in a normal medium. Which of
the following observation will be correct?[AIIMS 2007]
(a) Both the strands of DNA will be radioactive
(b) One strand radioactive
(c) Each half strand radioactive
(d) None is radioactive
28 .The strand of DNA acting as template for mRNA
transcription is
I.coding strand II. non-coding strand
III.sense strand IV. ant sense strand
The correct answer is
(a) I and III (b) I and IV
(c) II and IV (d) II and III
29 .Select the incorrect statement from the following
I.Each gene contains a specific promoter region and
a leader sequence for guiding the beginning of
transcription.
II.Only one strand of DNA called template strand is
copied by RNA polymerase this strand runs in
3 ′→ 5 ′ direction.
III.RNA polymerase adds complementary nucleotides
forming single stranded mRNA in 3 ′→ 5 ′ direction.
IV.Section of DNA that has been transcribed is
rewound into its original configuration.
(a) I and II (b) II and IV
(c) III and IV (d) None of these
5 ′
3 ′
A
5 ′
3 ′
B
Lagging strandC