Question 1 :
<i></i><i></i>The experimental system used in studies of the discovery ofreplication of DNA has been<br>

Question 2 :
According to Watson-Crick model, hydrogen bonding in a double-stranded DNA occurs between.

Question 3 :
Whichof the following biologists has been dubbed as the architect of molecular biology?

Question 6 :
Watson and Crick were awarded Nobel Prize for their finding of

Question 10 :
Which of the following is the co-factor for origin of life from pre-RNA?

Question 11 :
Which one of the following is the complementary sequence for the DNA with $5'$-CGTACTA-$3'$.

Question 13 :
What is the length of human DNA containing $6.6\times10^9$ bp nitrogen bases?

Question 16 :
Which one of the following combinations is found in DNA ?

Question 18 :
The two strands of double helix of DNA are linked together by hydrogen bonds between

Question 19 :
The number of purines in a segment of DNA molecule is 68. What will be the number of pyrimdines in this segment ?

Question 21 :
In the double helix model of DNA, what would bethe distance between two consecutive base pairs?

Question 23 :
In&#160; a dsDNA number of phosphodiester bonds are $3250$, then find the number of base pairs.

Question 24 :
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 26 :
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 28 :
The double helical model of the DNA was proposed by Watson and Crick based on that whatdata produced by Wilkins and Franklin?

Question 31 :
Calculate the number of nitrogen bases in E.coli, if the length of E.coli DNA is 1.36 mm.

Question 33 :
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 34 :
Identify the correct and incorrect statements.A. &#160;The four nucleotide bases are not necessarily present in DNA in exact equal proportions.B. &#160;The total amount of purines are equal to the total amount of pyrimidines.C. &#160;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 37 :
Due to the discovery of which of the following in 1980, the evolution was termed as RNA world?

Question 38 :
Which of the following experiments could produce evidence supporting the RNA world hypothesis?

Question 40 :
Which of the following is an estimated length of linker DNA?

Question 44 :
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 47 :
If there are 120 adenine molecules in a B-DNA<i> </i>double helical structure showing 20 coils, what is the number of pyrimidine nucleotides forming three hydrogen bonds in it?

Question 48 :
Desert temperature often varies between &#160;0 to 50$^o$C. The DNA polymerase isolated from a camel living in the desert will be able to synthesize DNA most efficiently at

Question 50 :
Which of the following act as an evidence for the RNA world hypothesis?

Question 51 :
Who among the following did not provide experimental proof for the semiconservative model of DNA replication?<br/>

Question 52 :
Which of the following is true of RNA, but not DNA?

Question 53 :
In a DNA molecule cytosine is 18%. Percentage of adenine would be _________.<br/>

Question 54 :
Match the following and choose the correct combination from the options given.<br/><table class="wysiwyg-table"><tbody><tr><td></td><td>Column-I</td><td></td><td>Column-II</td></tr><tr><td>A.</td><td>Walter Sutton</td><td>1.</td><td>Discovered penicillin</td></tr><tr><td>B.</td><td>Thomas Hunt Morgan</td><td>2.</td><td>Discovered the chromosomal basis of heredity</td></tr><tr><td>C.</td><td>James Watson</td><td>3.</td><td>Described the phenomenon of linkage and crossing over</td></tr><tr><td>D.</td><td>Alexander Fleming</td><td>4.</td><td>Discovered the double helical structure of DNA</td></tr></tbody></table>

Question 56 :
Choose the correct answer from the alternatives given :<br/>If Meselson&#160;and Stahls experiment is continued for four generations in bacteria, the ratio&#160;of $N^{15}$- $N^{15}$, $N^{14}$ - $N^{15}$, $N^{14}$ - $N^{14}$&#160; containing DNA in the fourth generation would be

Question 59 :
Hypothesis of ''African origin'' of man is based on the study of____________

Question 62 :
During splicing, the exons are joined and the enzyme which catalyzes this reaction is&#160;

Question 63 :
According to Watson and Crick's model of DNA, sequencing the deoxyribonucleotides are joined together by phosphodiester bond between

Question 66 :
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 67 :
Choose the correct answer from the alternatives given :<br>Whichof the following phenomena was experimentally proved by Meselson and Stahl?

Question 68 :
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 69 :
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&#160;(A : G : T : C :: 35 : 15 : 35 : 15) while&#160;that given to student B is (A : G : T: &#160;C :: 12 : 38 : 12 : 38). Which of the following statement is true?<br/>

Question 70 :
If percentage of cytosine is 18%, what will be the percentage of adenine?<br/>

Question 71 :
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 72 :
Out of A-T, G-C pairing, bases of DNA may exist in alternate valency state owing to arrangement called as

Question 73 :
A short length of DNA molecule has 80 thymine and 80 guanine bases. The total number ofnucleotids in the DNA fragment is

Question 74 :
Choose the correct answers from the alternatives given.<br>What is the function of DNA ligase in recombinant technology?

Question 76 :
Taylor conducted the experiments to semiconservative mode of chromosome replication on

Question 79 :
No. of of phosphoester bonds found in one turn of DNA is ____________.

Question 80 :
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?