Question 1 :
According to Watson-Crick model, hydrogen bonding in a double-stranded DNA occurs between.
Question 4 :
Which of the following is the co-factor for origin of life from pre-RNA?
Question 5 :
<i></i><i></i>The experimental system used in studies of the discovery ofreplication of DNA has been<br>
Question 7 :
What is the length of human DNA containing $6.6\times10^9$ bp nitrogen bases?
Question 11 :
Which one of the following is the complementary sequence for the DNA with $5'$-CGTACTA-$3'$.
Question 12 :
In the double helix model of DNA, what would bethe distance between two consecutive base pairs?
Question 13 :
The number of purines in a segment of DNA molecule is 68. What will be the number of pyrimdines in this segment ?
Question 14 :
Choose the correct answer from the alternatives given :<br>Ifthe sequence of nitrogen bases of the coding strand of DNA in a transcriptionunit is: 5 - A T G A AT G - 3, the sequence of bases in its RNA transcriptwould be
Question 15 :
Whichof the following biologists has been dubbed as the architect of molecular biology?
Question 16 :
In  a dsDNA number of phosphodiester bonds are $3250$, then find the number of base pairs.
Question 20 :
Watson and Crick were awarded Nobel Prize for their finding of
Question 23 :
Which one of the following combinations is found in DNA ?
Question 27 :
The two strands of double helix of DNA are linked together by hydrogen bonds between
Question 28 :
Histones are group of proteins which are rich in basic amino acids and they perform the function of
Question 30 :
One turn of the helix in a B-form DNA is approximately 
Question 31 :
Which of the following proves that RNA has the ability to act as catalyst?
Question 35 :
A double stranded DNA having 100,000 bp will have a length of
Question 38 :
Which of the following is an estimated length of linker DNA?
Question 40 :
Which organic molecule becomes catalyst in the presence of an enzyme?
Question 41 :
The width of B-DNA is ______ and each turn of its helix has ______ nucleotides.
Question 42 :
Choose the correct answer from the alternatives given :<br>ADNA template plus primer with the structure<br>3 <b>P</b> - TG C GAATTAG C GACAT - <b>P</b>5<br>5 <b>P</b> - ATCGGTACGACGCTTAAC OH 3<br>(where<b>P</b> = a phosphate group) is placed inan in vitro DNA synthesissystem containing $Mg^{2+}$, an excess of the four deoxyribonucleosidetriphosphates, etc. and a mutant form of E.Coli DNA polymerase I that lacks 5 $\rightarrow$ 3 exonucleaseactivity. The 5 $\rightarrow$ 3 polymerase and. 3 $\rightarrow$ 5exonuclease activities of this aberrant enzyme are identical to those of normalE. Coli DNApolymerase I. Itsimply has no 5 $\rightarrow$ 3 exonuclease activity. What will be thestructure of the final product?<br>
Question 44 :
If the total amount of adenine and thymine in a double-stranded DNA is 60% the amount of guainine in this DNA will be<br/>
Question 45 :
The double helical model of the DNA was proposed by Watson and Crick based on that whatdata produced by Wilkins and Franklin?
Question 50 : The relative percentages of nitrogenous bases of the genetic material isolated from various species (P, Q, R, S and T) are listed in the following table.<table class="wysiwyg-table"><tbody><tr><td>Species</td><td>Adenine</td><td>Guanine</td><td>Thymine</td><td>Cytosine</td><td>Uracil</td></tr><tr><td>P</td><td>$21$</td><td>$29$</td><td>$21$</td><td>$29$</td><td>$0$</td></tr><tr><td>Q</td><td>$29$</td><td>$21$</td><td>$29$</td><td>$21$</td><td>$0$</td></tr><tr><td>R</td><td>$21$</td><td>$21$</td><td>$29$</td><td>$29$</td><td>$0$</td></tr><tr><td>S</td><td>$21$</td><td>$29$</td><td>$0$</td><td>$29$</td><td>$21$</td></tr><tr><td>T</td><td>$21$</td><td>$29$</td><td>$0$</td><td>$21$</td><td>$29$</td></tr></tbody></table><br>Choose the correct statement from the following.<br>
Question 51 :
Under electron microscope, chromatin fibres appear like beads in a string. The beads are
Question 52 :
Which of the following act as an evidence for the RNA world hypothesis?
Question 53 :
Consider these sentences regarding the structure and nature of DNA.<br/>I. DNA has two pyrimidine bases that contain single ring structure.<br/>II. In DNA, composition of bases should be $\displaystyle\frac{A+T}{G+C}=1$.<br/>III. Each base pair of DNA is $3.4\overset{o}{A}$ apart from other base pairs.<br/>IV. The nucleosome model DNA packaging was proposed by Kornberg and Thomas.<br/>Choose the correct statements from the given options.<br/>
Question 55 :
A scientist is conducting an experiment in which she synthesized uridine triphosphate (uracil) using carbon-14 isotopes. She then adds the radioactively labeled molecules to the growth medium of a colony of living cells and allows the colony to incubate for 24 hours.<br><br>Upon examination, which of the following macromolecules should the scientist expect to be labeled inside the cell?
Question 56 :
Which of the following is true of RNA, but not DNA?
Question 57 :
Analysis of DNA of an organism revealed the following characters. Mark the option that is not likely to be true if the organism is a cat.
Question 58 :
Given the fact that histone binds DNA, it should be rich in.
Question 61 :
A short length linear double-stranded DNA molecule has 110 thymine and 110 guanine bases. The total number of nucleotide in the DNA fragment will be<br/>
Question 62 :
The bond formed between phosphate and pentose sugars of DNA is
Question 63 :
Identify the correct and incorrect statements.A.  The four nucleotide bases are not necessarily present in DNA in exact equal proportions.B.  The total amount of purines are equal to the total amount of pyrimidines.C.  DNA ligase enzyme act to hydrolyse or breakdown a polynucleotide chain into its component nucleotides.D. Nuclease enzymes are capable of restoring an intact DNA duplex.
Question 64 :
In one polynucleotide strand of a DNA molecule, the ratio of $A+T/G+C$ is $0.3$. What is the $A+G/T+C$ ratio of the entire DNA molecule?
Question 66 :
Choose the correct answers from the alternatives given :<br>Ifthe sequence of bases in DNA is TAGC, then the sequence of bases in RNA wouldbe
Question 67 :
A mixture of equal numbers of fast and slow dividing cells is cultured in a medium containing a trace amount of radioactively labeled thymidine for one hour. The cells are then transferred to regular (unlabelled) medium. After 24 hrs of growth in regular media.
Question 68 :
Choose the correct answers from the alternatives given :<br>Whichof the following is not a chemical component of deoxyribonucleic acid?
Question 71 :
In a double-stranded DNA, the sequence of base pairs in one strand is AGCTAAGC. What is the complementary sequence on the other strand?
Question 72 :
Assertion: The heterocyclic compounds in nucleic acid are the nitrogenous bases.
Reason: Adenine and guanine are substituted pyrimidines while uracil, cytosine and thymine are substituted purines.
Question 75 :
In the double helix model of DNA as proposed by Watson and Crick, each base pair is how far from the next base pair?
Question 77 :
A sample of DNA is found to have the base composition (mole ratio) of A = 40, T = 22, G = 21 and C = 17. This suggests
Question 78 :
If the length of DNA strand is ${ 68A }^{ \circ }$ then, what will be the number of nucleotides present in DNA molecule
Question 80 :
Choose the correct answers from the alternatives given :<br>Whichof the following regarding DNA is not true?
Question 81 :
Palaeontologists unearthed a human skull during excavation.  A small fragment of the scalp tissue was still attached to it. Only little DNA could be extracted from it. If the genes of the ancient man need to be analysed, the best way of getting sufficient amount of DNA from this extract is <br/>
Question 83 :
Choose the correct answers from the alternatives given.<br>What is the function of DNA ligase in recombinant technology?
Question 86 :
In the Watson and Crick model of DNA, the steps of the ladder are composed of
Question 87 :
Choose the correct answer from the alternatives given :<br>Referto the given steps Of DNA replication.<br>(i)Exposure of DNA strands<br>(ii)Synthesis of RNA primer<br>(iii)Activation of deoxyribonucleotides<br>(iv)Chain formation<br>(v)Base pairing<br>(vi) Proof reading and DNA repair<br>(vii)DNA polymerase attaches at Or site<br>Selectthe correct sequence of DNA replication.<br>
Question 88 :
If percentage of cytosine is 18%, what will be the percentage of adenine?<br/>
Question 89 :
Choose the correct answer from the alternatives given :<br>Watson and Crick (1953) proposed DNA double helix model and won the Nobel Prize; their model of DNA was based on<br><b></b>(i) X-ray diffraction studies of DNA done by Wilkins and Franklin<br>(ii) Chargaffs base equivalence rule<br>(iii) Griffiths transformation experiment<br>(iv) Meselson and Stahls experiment.<br>
Question 90 :
<i>E. coli</i>, to be replicated, is placed in a medium containing radioactive thymidine for five minutes. Then it is made to replicate in a normal medium. Which of the following observation will be correct ?
Question 92 :
Two students are given two different double stranded DNA molecules of equal length. They are asked to denature the DNA molecules by heating. The DNA given to student A has a following composition of base (A : G : T : C :: 35 : 15 : 35 : 15) while that given to student B is (A : G : T:  C :: 12 : 38 : 12 : 38). Which of the following statement is true?<br/>
Question 95 :
Watson & Crick proposed the model of DNA structures in which of the following years?<br/>
Question 98 :
A short length of DNA molecule has 80 thymine and 80 guanine bases. The total number ofnucleotids in the DNA fragment is
Question 99 :
Nobel Prize to A. Kornberg and S. Ochoa was given for
Question 100 :
Why does synthesis of DNA proceed only in the $5'$ to $3'$ direction?
Question 101 :
No. of of phosphoester bonds found in one turn of DNA is ____________.
Question 102 :
"It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for genetic material" - This is written by<br/>
Question 105 :
Out of A-T, G-C pairing, bases of DNA may exist in alternate valency state owing to arrangement called as
Question 106 :
Assertion: Histones are basic proteins of major importance in packaging of eukaryotic DNA. DNA and histones comprise chromatin forming the bulk of eukaryotic chromosome.
Reason: Histones are of five major types: H1, H2A, H2B, H3 and H4.
Question 107 :
A $340\overset {\circ}{A}$ long segment of DNA molecule has $20$ thymine nitrogenous bases, what will be the number of guanine nitrogen bases in the same segment?
Question 108 :
Transfer of DNA bands from an agarose gel to a nitrocellulose or nylon membrane is referred to as
Question 112 :
DNA in the nucleus of rabbit egg is 1.8 picograms, its liver cell will have mass of DNA ______ picograms.
Question 113 :
Read the following statements and select the Correct option.<br>(i) Loosely packed and lightly stained region of chromatin are called as heterochrormatin.<br>(ii) Densely packed and dark stained region of chromatin are called as euchromatin.<br>(iii) A typical nucleosome contains 200 bp of DNA helix.<br>
Question 114 :
Choose the correct answer from the alternatives given :<br>Whichof the following phenomena was experimentally proved by Meselson and Stahl?
Question 115 :
If the total amount of adenine and thymine in a double-stranded DNA is 45%, the amount of guanine in this DNA will be<br/>
Question 117 :
Taylor conducted the experiments to semiconservative mode of chromosome replication on
