Biotechnology and its Applications MCQs for NEET — Zoology Questions with Answers

(c) 'Himgiri' is a wheat variety resistant to leaf and stripe rust, hill bunt, etc.

(d) The superiority of hybrids over either of the parents (dominant or recessive is called hybrid vigour (G. Shull). Heterosis is equivalent of hybrids vigour.

(b) Biofortification is a method of breeding crops to increase their nutritional value. This can be
done either through conventional selective breeding or through genetic engineering. Biofortification differs from, ordinary fortification because it focuses on making plant foods more nutritious as the plants are growing rather than nutrients added to the food when they are being processed. This is an
improvement on ordinary fortification, when it comes to provide nutrients for the rural poor, who rarely have access to commercially fortified foods.

(a) Somaclones are obtained by tissue culture. The plant regenerated from cell and tissue cultures shows heritable variation for both qualitative and quantitative traits.

Plant breeding is the branch of Biology, which is concerned with developing varieties superior to existing ones.

Irradiation means exposure to any form of radiation

Genetic engineering is defined as the manipulation of genes by man.

(b) The plants obtained through genetic engineering contain a gene or genes usually from an unrelated organism, such genes are called transgenes and the plants containing transgenes are known as transgenic plants. These plants are often called as genetically modified or GM crops, eg, Flavr savr tomatoes, golden rice. Plants are made transgenic for identification, expressing the gene activity in tune, to produce several chemicals like fatty acids, sugars, cellulose, rubber, etc.

(b) In cloning of cattle a fertilized egg divides in 2, then in 4 and then in 8. This embryo is carefully removed from the womb. The embryonic cells are then separated using enzyme. Each isolated cell is kept in a nutrient medium and later implanted in the womb of a different 'host mother' cow.

(b) Hybrid varieties were first developed in maize, which is a cross-pollinated crop. In such crops, the parents of hybrid varieties are ordinarily, inbred lines. An inbred line is a nearly homozygous line produced by continuous inbreeding in a cross-pollinated crop and is maintained by strict inbreeding. In maize, hybrid vigour or heterosis is exploited by the crossing of two inbred parental lines.

(a) A plant in which a gene has been transferred through genetic engineering is called a transgenic plant and the gene, so transferred is called a transgene. Golden rice is a promising transgenic crop which when released for cultivation will help in alleviation of vitamin A deficiency.

These hormones are used in the dairy industry, when injected into cows would increase their milk production.

NCERT page number -175

Table -9.2

9.2.3 Plant Breeding For Developing Resistance to insect pests

Strategies For Enhancement In Food Production