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No, as exonuclease acts on the free ends of linear DNA molecule. Therefore, instead of producing DNA fragments with sticky ends, it will shorten or completely degrade the DNA fragment containing the gene of interest, and the circular plasmid (vector) will not get cut as it lacks free ends.

It is a method of cellular defense in eukaryotic organisms, which involves silencing of m.RNA.

The recombinant therapeutics do not induce any unwanted immunological response like the similar products of non human origin such therapeutics are highly effective.

The principle is antigen-antibody interaction.

The applications of biotechnology include 

• Molecular diagnostics
• Bioremediation
• Waste treatment
• Energy production
• Therapeutics.

• Pathogens are detected by the presence of antigens, which may be a protein or glycoprotein.
• Pathogens can be also be detected by the presence of antibodies synthesized against the pathogens

Traditional knowledge is exploited to

• Develop modem applications of the resources 
• Save time, effort, expenditure in the process of commercialisation of bio-resources.

• Use of improved verities of crops
• Employing better management practice
• Use of agrochemical such as fertilizers and pesticides

The two Indian patents include

• Pesticide property of neem
• Healing and antiseptic property of turmeric.

PCR (POLYMERASE CHAIN REACTION)

DNA synthesis

(b) Size only

(b) exonuclease

(d) All the above

A recombinant DNA molecule can be E.coli

Thermus aquaticus

RNA Interference (RNAi) is a gene-silencing process that blocks the expression of genes in the parasite when it enters the host's body.  

RNAi is a method adopted to prevent infestation of roots of tobacco plants by a nematode Meloidegyne incognitia. In RNAi, a complementary RNA binds to mRNA to form a ds RNA that cannot translate and hence, its expression is blocked (Silencing). In this process, nematode-specific genes (DNA) are introduced in the host plant. This introduced DNA forms both sense and anti-sense RNA. These two strands, being complementary to each other, bend and form ds RNA, leading to RNA interference. mRNA of nematode is thus silenced and the parasite cannot survive in the transgenic host.  

Thus, through the above method, tobacco plants can be protected from nematode attack.

a. The three steps involved in polymerase chain reaction (PCR):

i. Denaturation of double stranded DNA (dsDNA) at high temperature.

ii. Annealing of two sets of primers.

iii. Extension of primers to form dsDNA by Taq polymerase and deoxynucleotides.

b. Source organism of Taq polymerase is the bacterium Thermus aquaticus. This enzyme is heat tolerant and repeatedly amplifies DNA at high temperatures.

Make decisions regarding the validity of GM research and to take decision to ensure safety of introducing GM organism for public services and consumption.

Holstein cow provides about 6000 litres of milk per year.

myc and ras oncogenes are being analyzed in transgenic mice to find out their role in development of breast cancer.

1. Transgenic mice are used in various research areas of cancer research.

2. Transgenic mice containing a particular oncogene (cancer causing gene) develop specific cancer. 

3. They are used to study the relationship between oncogenes and cancer development, cancer treatment and prevention of malignancy. 

4. The transgenic mouse model for the investigation of the breast cancer was developed in the laboratory of Philip Leder in Harvard (USA). 

5. Transgenic mice containing oncogenes myc and ras were analyzed to find out role of these genes in the development of breast cancer.

Gene therapy is the treatment of genetic disorders by replacing, altering or supplementing a gene that is absent or abnormal and whose absence or abnormality is responsible for the disease. Types of gene therapy: 

(a) Germ line gene therapy:

1. In this germ cells are modified genetically to correct a genetic defect.

2. Normal gene is introduced into germ cells like sperms, eggs, early embryos. 

3. It allows transmission of the modified genetic information to the next generation. 

4. Although it is highly effective in treatment of the genetic disorders, its use is not preferred in human beings because of various technical and ethical reasons.

(b) Somatic cell gene therapy:

1. In this somatic cells are modified genetically to correct a genetic defect. 

2. Healthy genes are introduced in somatic cells like bone marrow cells, hepatic cells, fibroblasts endothelium and pulmonary epithelial cells, central nervous system, endocrine cells and smooth muscle cells of blood vessel walls.

3. Modification of somatic cells only affects the person being treated and the modified chromosomes cannot be passed on the future generations. 

4. Somatic cell gene therapy is the only feasible option and the clinical trials have already employed for the treatment of disorders like cancer, rheumatoid arthritis, SCID, Gaucher’s disease, familial hypercholesterolemia, haemophilia, phenylketonuria, cystic fibrosis, sickle-cell anaemia, Duchenne muscular dystrophy, emphysema, thalassemia, etc.

1. Plasmids are small, extra-chromosomal, double stranded circular forms of DNA that replicate autonomously. 

2. They are seen in bacterial cells, yeast and animal cell. 

3. Plasmids are considered as replicons as they are capable of autonomous replication in suitable host. 

4. The most commonly used vectors in r-DNA technology are plasmids as they replicate in E. coli.

Plasmid as a cloning vector should have a replication origin, a marker gene for antibiotic resistance, control elements like promoter, operator, ribosome binding site, etc. and a region where foreign DNA can be inserted. Naturally plasmids do not have all these features. Hence, they are constructed by inserting gene for antibiotic resistance. pBR 322, pBR320, paCYC177 are the constructed plasmids. 

Ti plasmid (for tumor-inducing) of Agrobacterium tumefaciens is an important vector for carrying new DNA in many plants. It contains a transposon, called T DNA, which inserts copies of itself into the chromosomes of infected plant cells. The transposon, with the new DNA, can be inserted into the host cell’s chromosomes. A plant cell containing this DNA, can then be grown in culture or induced to form a new, transgenic plant.

The reasons that could be possible are as follows:

i. DNA sample that was loaded on the gel may have got contaminated with nuclease (exo- or endo- or both) and completely degraded.

ii. Electrodes were put in opposite orientation in the gel assembly, i.e., anode towards the wells (where DNA sample is loaded). Since DNA molecules are negatively charged, they move towards anode and hence move out of the gel instead of moving into the matrix of gel.

iii. Ethidium bromide was not added at all or was not added in sufficient concentration and so DNA was not visible.

iv. After staining with Ethidium bromide it was not observed under UV

Specific growth rate- 1.1515 hr^-1

Doubling time- 0.693/1.1515=0.6 hours=36 minutes

Exponential phase

Mad cow disease caused by prion/ rogue protein. 

Selectively removing a gene and making other precise genetic modifications in the mouse ES cells and creating mouse models of human disease.