Q.(a)

(a) Groundnut, Arachis hypogaea (Fabaceae), is economically valuable for oil, feed, food, soil fertility and industrial uses; (b) DNA recombinant technology builds and expresses a recombinant gene in a host through isolation, cutting, ligation, transformation, selection and expression.

(a) Groundnut: binomial, family and economic importance

The binomial name of groundnut is Arachis hypogaea, and it belongs to the family Fabaceae (Leguminosae, sub-family Papilionoideae/Papilionaceae).

Five points of economic importance:

1. Edible oil: the seeds are rich in oil (about 40-50%) and are a major source of edible groundnut (peanut) oil used widely in cooking.
2. Oil cake: the residue left after oil extraction is rich in protein and is extensively used as cattle/poultry feed, and also as organic manure.
3. Direct food use: the seeds are consumed directly (roasted, boiled, or as peanut butter) and are an important, protein- and fat-rich dietary source, especially in vegetarian diets.
4. Soil fertility improvement: being a legume, its roots bear nodules containing the nitrogen-fixing bacterium Rhizobium, which fixes atmospheric nitrogen into the soil, improving soil fertility; hence it is valuable in crop rotation with cereals.
5. Industrial uses: the oil is also used in the manufacture of soap, cosmetics and lubricants, and the plant residue (haulms) after harvest is used as fodder.

(b) DNA recombinant technology: definition and events

Definition: DNA recombinant technology (genetic engineering) is the technique in which a desired gene/DNA segment from a donor organism is isolated and combined (recombined) with a vector DNA (such as a plasmid) to construct a recombinant DNA molecule, which is then introduced into and expressed within a suitable host organism to obtain multiple copies of the gene and/or its protein product.

Key events/steps:

1. Isolation of the desired DNA/gene: the DNA carrying the gene of interest is isolated from the donor organism.
2. Cutting (restriction digestion): both the donor DNA and the vector DNA are cut using specific restriction endonucleases, generating matching (often sticky) ends.
3. Ligation: the cut gene fragment is joined/inserted into the cut vector using the enzyme DNA ligase, forming the recombinant DNA molecule. …