Retroviruses Have No Dna. However, the Dna of the Infected Host Cell Does Possess Viral Dna. How is It Possible? - Biology


Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?



Retroviruses have RNA as genetic material. After the entry of a virus into the body of the host, the virus attacks the macrophage cells of the body where the RNA genome of the virus replicates to form viral DNA with the help of the reverse transcriptase enzyme.

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2014-2015 (March) All India Set 1


What would be the molar concentration of human DNA in a human cell? Consult your teacher.

Describe briefly the following:

Origin of replication


Give an account of the Blue-White Method of selection of recombinants

One of the major contributions of biotechnology is to develop pest-resistant varieties of cotton plants. Explain how it has been made possible.



Name and explain the technique used for separating DNA fragments and making them available for biotechnology experiments.

Expand the following abbreviation: BAC

What are the restriction endonucleases? Give the rules of their nomenclature.

Describe two vectors less methods of gene transfer used in rDNA technology.

Why are bio-fertilizers preferred over chemical fertilizers?

What is the cell that receives a recombinant gene called?

In vitro amplification of DNA or RNA segment is known as ___________.

The recognition sequence of restriction enzymes is generally ______ nucleotide long.

The technique which involves addition or deletion of genes is ______.

ECoRI is obtained from ______.

Alu-I is obtained from which organism?

What is the role of Taq-polymerase in PCR technology?

Define vector? write any two examples,

What is gene cloning? Explain different tools used for it.

Identify the palindromic sequence which is recognized by the EcoRI restriction enzyme.

From the following which one is NOT a feature of the plasmids?

Which of the following is TRUE regarding EcoR I?

For which of the following purpose restriction endonuclease enzyme is used in genetic engineering?

Identify the characterization techniques that are based on molecular weights of compounds.

Which of the following is the right combination of primers in a PCR to amplify the DNA product?

Following are the four statements regarding separation of DNA fragments using Gel electrophoresis. Identify the INCORRECT statements.

i. DNA is negatively charged molecule and so it is loaded on gel towards the Anode terminal.

ii. DNA fragments travel along the surface of the gel whose concentration does not affect movement of DNA.

iii. Smaller the size of DNA fragment, larger is the distance it travels through it.

iv. Pure DNA can be visualized directly by exposing to UV radiation.

Polymerase Chain Reaction is made possible by ____________.

A technique used to make numerous copies of a specific DNA segment quickly and accurately is called ______

The main reason for the presence of both a leading and a lagging strand during DNA replication is, ______ 

The rDNA technology has provided a method to control the nematode parasite Meloidogyne incognita. Explain the principle involved in this technique.

Which of the following statements is correct with respect to cellular respiration?

Which of the following viruses has the capacity to produce lysozymes?

Which one is a true statement regarding DNA polymerase used in PCR?

The source of taq Polymerase used in PCR is a ______.

A hind of biotechnology involving manipulation of DNA is ______.

What is true for plasmid?

Nucleic acid segment tagged with a radioactive molecule is called ______.

DNA fingerprinting refers to ______.

The most important feature in a plasmid to serve as a vector in gene cloning experiment is ______.

Name a recombinant vaccine that is currently being used in vaccination program?

What is meant by gene cloning?

What would happen when one grows a recombinant bacterium in a bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?

Oil spill is a major environmental issue. It has been found that different strains of Pseudomonas bacteria have genes to break down the four major groups of hydrocarbons in oil. Trials are underway to use different biotechnological tools to incorporate these genes and create a genetically engineered strain of Pseudomonas - a ‘super-bug’, to break down the four major groups of hydrocarbons in oil. Such bacteria might be sprayed onto surfaces polluted with oil to clean thin films of oil.

(a) List two advantages of using bacteria for such biotechnological studies?

(b) For amplification of the gene of interest PCR was carried out. The PCR was run with the help of polymerase which was functional only at a very low temperature. How will this impact the efficiency of the PCR? Justify.

(c) If such bacteria are sprayed on water bodies with oil spills, how will this have a positive or negative effect on the environment? Discuss.

Observe the given sequence of nitrogenous bases on a DNA fragments and answer the following questions:


  1. Name a restriction enzyme which can recognise this DNA sequence.
  2. Write the sequence after digestion.
  3. Why are the ends generated after digestion called sticky ends?

Expand the following acronym:


Which vector is mostly used in rDNA technology in plants?

Which of the following enzyme catalyses the removal of nucleotides from the end of DNA molecules?

What is polymerase chain reaction (PCR)?

Describe three steps involved in mechanism of PCR.

The DNA polymerase enzyme used in PCR is obtained from______.

How gene amplification is done?

______technique is used for in vitro gene cloning or gene multiplication.

What is EcoRI?

Importance of PCR.

Expand YAC used in the field of Biotechnology.

Name the source of thermostable DNA polymerase.

How many sets of primers are required in each cycle of PCR?

Which one of the following enzymes is used to join DNA fragments? 

Give a reason for the following:

DNA cannot enter directly into the host cell.


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