The various components are water, agar, a source of carbon (e.g. sucrose), inorganic salts, vitamins, amino acid and growth hormones (e.g. auxins, cytokinin, etc).

Micropropagation is used to produce thousands of plants in very short durations of time.

The meristem is the plant part that is best suited for making virus-free plants. This is because even when the plant is infected with a virus, the meristem (apical and axillary) remains infection free; it can be removed, grown in vitro to obtain virus-free plants. 

1. The C-peptide is removed.
2. The peptides A and Bare joined.by disulphide bridges.

In 1983, Eli Lily and American company prepared two DNA sequences corresponding to A and B, chains of human insulin, introduced them in plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin.

Pathophysiology is the study of functional chenges in the body of the host that occur in response to any disease or injury, e.g. if someone ingests a toxin, it may result into a variety of physical changes, such as inflammation in the stomach lining.

The areas in recent advances in biochenology are 
(i) Agriculture
(ii) Medicine
(iii) Food industry
(iv) Fermentation technology
(v) Environmental engineering, and
(vi) Genetic engineering.

It involves metabolic engineering to transform an oil (hydrocarbon) producing seed into an oil-less seed.This can be done by identifying the specific enzyme involved in the biosynthesis of oil and then repressing the gene responsible for synthesizing that particular enzyme.

Eli Lilly prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids ofE. cold to produce insulin chains. Chains A and B were produced separately,
extracted and combined by creating disulfide bonds to form human insulin. Insulin in human pancreas is synthesised as a pro-hormone containing the C peptide, which is removed in mature hormone. The synthesised insulin did not contain C peptide and was prepared in m form.

Golden rice is a genetically modified rice with high levels of β-carotene and other carotenoids. This rice is modified in order to enhance the quantity of vitamin-A in it. It is called golden due to the gold-like colour it gets from β -carotene.

No; blood has no proteases and nucleases.

(i) Trangenic animals are the animals with the modified genome. A foreign gene is inserted into the genome of the animal to alter its DNA. This method is done to improve the genetic traits of the target animal. Initially, the improvement of genetic traits was done by selective breeding methods.
(ii) The first transgenic cow was named 'Rosie'. which was invented in 1997. It is helpful in the production of human protein-enriched milk. The protein in milk was about 2.4 grams per litre. The milk has alpha-lactalbumin and it is a balanced food for human babies.

Cloning is the process of introducing a desired gene into a host like E.coli.  The desired gene is inserted into a vector (plasmid) which basically acts as a vehicle to carry the desired gene into an organism in which we intend to express the gene of our interest.

1. RNA interference (RNAi) occurs as a method of cellular defence in all eukaryotic organisms.
2. It involves the silencing of a specific mRNA by a complementary dsRNA.
3. The complementary RNA for making the doublestranded RNA comes either from an infection by RNA viruses or mobile genetic elements, called transposons, which replicate through an RNA intermediate.
4. The nematode-specific genes are introduced into the host plant, using Agrobacterium tumefaciens as vector, in such a way that it produced both sense and anti-sense RNA in the host. 5. The sense and antisense RNAs are complementary to each other and form dsRNA.
6. The dsRNA binds to and prevent the translation of a specific mRNA.
7. Consequently, the parasite is not able to live in the transgenic tobacco plant and hence the plant is protected.

Bt cotton plants are the transgenic plants that express a Bacillus thuringiensis gene called cry gene. This gene, encodes for protein crystals having insecticidal properties against insects of group Lepidoptera, Diptera and Coleoptera. Inside the bacterium, these proteins remain inactive and do not harm the bacteria. However, these inactive crystals can get activated in the alkaline pH of the gut of insects upon ingestion.
After activation, these crystals can bind to the receptors present on the membranes of gut epithelial cells. Due to this binding, the membrane swells and pores are created on them. These pores lead to bursting of cell. Hence, soon the lepidopteran dies due to starvation.

The major problem here is that the proteins with a short half lives are not orally active and are not absorbed properly.
An orally active protein should be metabolically stable and have a longer half life, so that it is not degraded fast and absorbed efficiently.
To make orally active protein drug, the site directed mutagenesis can be used to redesign their genes for the expression of a modified peptide.

Genetically modified organisms are the living organisms (plants, animals, or bacteria) which have been genetically 'engineered' by the insertion of a foreign gene (a transgene).

Cry proteins are the crystal proteins that are toxic to certain insect pests (Dipterans, Coleopterans and Lepidopterans).
They are produced by the bacterium Bacillus thuringiensis .
Man has isolated the genes encoding these proteins from this bacterium and incorporated into some crop plants; such crop plants produce the proteins in their cells and are resistant to the attack by these insect pests.

Bacteria that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic bacteria, eg. DNA sequences introduced in plasmid of E. coli to produce insulin chains.

(i) Animals that have had their DNA manipulated to possess and express an extra foreign gene are known as transgenic animals.
(ii) No, each cow would produce only a limited amount of medicinal milk before it dies. This means lives of many cows would be compromised for the production of substantial amount of medicinal milk, for the advantage of humans.
(iii) Some laws have been passed by the Government and agencies monitoring the genetic engineering researches to maintain ethics of life, and to regulate such acts.
(iv) Sympathy towards animals, ethics, respect for living organisms.

Transgenic animals: Transgenic animals are produced for the following purposes:
(i) Transgenic animals are designed to allow the study of how genes are regulated and how they affect the normal functions of the body and its developments e.g. Information is obtained as to how insulin has a role as growth factor.
(ii) Transgenic animals are designed to increase our understanding as to how genes control the development of diseases; they serve as models for human diseases.
(iii) Transgenic animals that produce useful biological compounds are created by introducing a portion of the DNA that codes for that product, e.g.
\(\alpha \) -L antitrypsin is produced for curing emphysema.
(iv) Transgenic mice are being developed to test the safety of vaccines, e.g., polio vaccine has been tested on mice.
(v) Transgenic animals with more sensitivity to toxic substances are being developed to test the toxicity of drugs.

Gene therapy is a collection of methods, that allows correction or replacement of a defective gene.
Correction of a genetic defect involves delivery of a normal gene into the individual's embryo to take over the function of the non-functional gene.
ADA (Adenosine deaminase) deficiency was treated in a 4 year old girl.
This disorder is caused by the deletion of the gene for the enzyme.
The lymphocytes from the blood of the patient are grown in a culture in vitro.
A functional ADA cDNA (using retroviral vector) is introduced into lymphocytes; such lymphocytes are introduced back into the blood of the patient.
But the patient requires periodic infusion of such genetically-engineered lymphocytes.
 If the gene isolated from marrow cells is introduced in cells in the early stage, it could be a permanent cure.

Advantages:
(i) Genetic modification has made the crops more tolerant to abiotic stresses like cold, heat, drought, salinity, etc.
(ii) It has reduced the dependence of crops on chemical pesticides as they are made pest-resistant.
(iii) Post-harvest losses are much reduced.
(iv) As the plants have increased efficiency of mineral usage by plants, the early exhaustion of fertility of soil is prevented.
(v) Food produced from GM (Genetically Modified) crops has enhanced nutritional value.
(vi Genetic modification has been used to create tailor-made plants to supply resources to industries such as starch, fuels, pharmaceuticals, etc.
Disadvantages:
The proteins produced by the GMO may cause allergy and other problems.
The genes present in the transgenic organisms may transform our intestinal bacteria also resistant to certain antibiotics.
When the resistant gene is transferred through pollen to the weeds, they may also become resistant to such pests and start flourishing.

(a) Colony 4 got transformed as it failed to grow on agar containing ampicillin and tetracycline. Since, it is transformed, its gene for tetracycline and ampicillin resistance became inactive, thus it lost its ability to grow in both of them (ampicillin and tetracycline).
(b) Selectable markers are sites where ampicillin and tetracycline resistance genes are inserted. They are very important in genetic engineering as they help in the selection of the transformants from those of the non- transformants.
(c) EcoRI, Hind III
Or
(c) \(\beta\)- galactosidase acts as a reporter enzyme. It is produced by lac z, a reporter gene. In insertional inactivation, when there is inactivation of lac z gene due to insert , no B- galactosidase is formed and thus no blue colour in formed. Thus, giving a white coloured colonies of transformants.

(i) The production of genetically modified crops has increased with increasing timespan due to the benefits that the GM crops give.Therefore, this scenario is completely justified. GM plants have benefitted us in increased yield and qualities like stress tolerance, etc., therefore, growing GM crops has become favourable for the farmers as they bring much benefits.
(ii) No, genetically engineered crops do not favour/offer post-harvest losses. They help farmers in minimising crop losses which occur due to insects and/or diseases.
(iii) Two advantages are
(a) Production of disease and drought resistant plants.
(b) Increased production of food with longer self life.
or
(iii) Transgenic plants/crops have certain adverse effects on humans. These include
(i) They may be allergic to humans.
(ii) They may transfer antibiotic resistance to humans.