Semiconservative Replication

Q.

Who proved that DNA is genetic material?

Q.

What happens to the unzipped DNA molecule?

Q.

Who discovered central dogma?

Q.

What Is The Importance Of The Replication Process?

Q. Taylor conducted the experiments to prove semiconservative mode of chromosome replication on

1. E. coli
2. Vinca rosea
3. Vicia faba
4. Drosophila melanogaster

Q. Why DNA replication is called semiconservative?

Q. Describe Meselson and Stahl's experiment that was carried in 1958 on E. coli. Write the conclusion they arrived at after the experiment.

Q. The technique used by Taylor to explore the nature of DNA replication in Vicia faba is __________________.

1. autoradiography
2. chromatography
3. density gradient centrifugation
4. autoradiography and chromatography

Q.

What did Hershey and Chases experiment prove?

Q. Paragraph for below question
In living cells, such as E. coli, the process of replication requires a set of catalysts. The main enzyme is referred to as DNA dependent DNA polymerase. Any mistake during replication would result into mutations. Furthermore, energetically replication is a very expensive process. Deoxyribonucleoside triphosphates serve dual purposes. In addition to acting as substrates, they provide energy for polymerisation reaction. In addition to DNA polymerases, many additional enzymes are required to complete the process of DNA replication.
Q. Select the incorrect statement about DNA polymerase.

नीचे दिए गए प्रश्न के लिए अनुच्छेद
सजीव कोशिकाओं जैसे ई. कोलाई में प्रतिकृतीयन की प्रक्रिया हेतु उत्प्रेरकों के समूह की आवश्यकता होती है। मुख्य एंजाइम जो DNA पर निर्भर है वह DNA पॉलीमरेज है। प्रतिकृतीयन में किसी भी तरह की त्रुटि के परिणामस्वरूप उत्परिवर्तन होता है। इसके अतिरिक्त, ऊर्जा की दृष्टि से प्रतिकृतीयन एक महँगी प्रक्रिया है। डिऑक्सीराइबोन्यूक्लियोसाइड ट्राइफॉस्फेट दोहरे उद्देश्य की पूर्ति करते हैं। क्रियाधार के रूप में कार्य करने के अतिरिक्त, ये बहुलकीकरण अभिक्रिया के लिए ऊर्जा प्रदान करते हैं। DNA प्रतिकृतीयन की प्रक्रिया को पूर्ण करने हेतु DNA पॉलीमरेज के अतिरिक्त, कई अन्य एंजाइमों की आवश्यकता होती है।
प्रश्न: DNA पॉलीमरेज के संबंध में गलत कथन का चयन कीजिए।

1. It cannot initiate the process of replication
   यह प्रतिकृतीयन की प्रक्रिया को प्रारंभ नहीं कर सकता है
2. It uses a DNA template to catalyse the polymerisation of deoxynucleotides
   यह डिऑक्सीन्यूक्लियोटाइड्स के बहुलकीकरण को उत्प्रेरित करने के लिए DNA टेम्पलेट का उपयोग करता है
3. It catalyses the polymerisation of ribonucleotides during transcription
   यह अनुलेखन के दौरान राइबोन्यूक्लियोटाइड्स के बहुलकीकरण को उत्प्रेरित करता है
4. It polymerises only in one direction that is $5^{\prime }\to 3^{\prime }$
   यह केवल एक ही दिशा, $5^{\prime }\to 3^{\prime }$ में बहुलकीकरण करता है

Q.

What lead to expansion of D loop?

Q. [5]
(a) State the 'Central dogma' as proposed by Francis Crick. Are there any exceptions to it? Support your answer with a reason and an example.

(b) Explain how the biochemical characterisation (nature) of 'Transforming Principle' was determined, which was not defined from Griffith's experiments.

Q. What will be the ratio of ${}^{15}N{/}^{15}N{:}^{15}N{/}^{14}N{:}^{14}N{/}^{14}N$ containing $DNAs$, if Meselson and Stahl experiment is continued for four generations in $E.coil$?

Q. Matthew Meselson and Franklin Stahl grew E. coli(doubling time is $20$min) in medium containing ${}^{15}N{H}_{4}Cl$ for many generations. Then the E. coli was transferred to medium containing ${}^{14}N{H}_{4}Cl$. After $40$ minutes, the cells were harvested and DNA was extracted and subjected to cesium chloride density gradient centrifugation. The proportion of light and hybrid DNA densities will be.

1. $100\%$ light DNA
2. $50\%$ light and $50\%$ hybrid DNA
3. $100\%$ hybrid DNA
4. $25\%$ light and $75\%$ hybrid DNA

Q. In the case of double-stranded DNA, which of the following base ratios are always equal to one?
a. $(A+T)/(G+C)$
b. $(A+G)/(C+T)$
c. $C/G$
d. $(G+T)/(A+C)$
Select the correct answer.

1. $1$ and $2$
2. $2$ only
3. $2,3$ and $4$
4. $1,3$ and $4$

Q. A polygenic trait is controlled by $3$ genes $A,B$ and $C$. In a cross $AaBbCc\times AaBbCc$, the phenotypic ratio of the offsprings was observed as
$1:6:x:20:x:6:1$ What is the possible value of $x$?

1. $3$
2. $9$
3. $15$
4. $25$

Q. Taylor conducted the experiments to provide semiconservative mode of chromosome replication on

1. Drosophila melanogaster
2. E. coli
3. Vinca rosea
4. Vicia faba

Q.

Match the lists and find the correct option:

$\begin{array}{cc}\text{I}& \text{II}\\ \text{(a) Colony hybridisation}& \text{1. Transfer of recombinant DNA into host cell}\\ \text{(b) Gel electrophoresis}& \text{2. Selection of cells containing the desired gene}\\ \text{(c) Gradient centrifugation}& \text{3. Separation of DNA fragments}\\ \text{(d) Polymerase chain reaction}& \text{4. Purification of DNA}\\ & \text{5. Gene cloning in thermocycler}\end{array}$

1. a –3, b –4, c –5, d –2
2. a – 4, b –5, C –2, d –3
3. a – 1, b – 2, c – 3, d –4
4. a – 2, b –3, c – 4, d –5

Q. 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 observations will be correct?

1. Both the strands of DNA will be radioactive
2. One strand radioactive
3. Each half strand radioactive
4. None is radioactive

Q. Assertion :In recombinant DNA technology, human genes are often transferred into bacteria (prokaryotes) or yeast (eukaryote). Reason: Both bacteria and yeast multiply very fast to form huge population which expresses the desired gene.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
3. Assertion is correct but Reason is incorrect.
4. Both Assertion and Reason are incorrect.

Q.

What does the process of DNA Replication necessitate?

Q. In bacteria, where and in which phase of cell cycle does DNA replication occur?

Q. The semiconservative nature of replication of DNA is observed in all organisms.

1. False
2. True

Q. DNA replication is

1. Conservative
2. Non-conservative
3. Semi-conservative
4. Constitutive

Q. The technique used by Taylor to explore the nature of DNA replication in Vicia faba is __________________.

1. autoradiography
2. chromatography
3. density gradient centrifugation
4. autoradiography and chromatography

Q. $DNA$ replication is

Q. Taylor conducted the experiments to provide semiconservative mode of chromosome replication on

1. Drosophila melanogaster
2. E. coli
3. Vinca rosea
4. Vicia faba

Q. Semiconservative replication of DNA was studied in E. coli with the help of ${}^{15}N$ by

1. Watson and Crick
2. Kornberg and Ochoa
3. Meselson and Stahl
4. Luria and Delbruck

Q. Meselson and Stahl conducted an experiment in which the double-stranded DNA helix when replicated, each of the two new double-stranded helices consisted of one strand from the original helix and one newly hypothesis of DNA does this experiment support?

1. Semi-conservative
2. All of the above
3. Dispersive
4. Conservative

Q. Choose the correct answer from the alternatives given :
Refer to the given steps Of DNA replication.
(i) Exposure of DNA strands
(ii) Synthesis of RNA primer
(iii) Activation of deoxyribonucleotides
(iv) Chain formation
(v) Base pairing
(vi) Proof reading and DNA repair
(vii) DNA polymerase attaches at Or site
Select the correct sequence of DNA replication.

1. (vii), (iii), (i), (ii), (v), (iv), (vi)
2. (iii), (i), (vii), (ii), (v), (iv), (vi)
3. (vii), (i) , (iii), (ii), (v), (iv), (vi)
4. (i), (iii), (ii), (vii), (v), (iv), (vi)