Category: Biology Second Paper

(i) Sheep farming is a good business in Australia. Wool and meat are obtained from sheep. Sheep eat grass like clover. Clover grass is low in sulfur and does not improve wool. Transgenic clover grass has been created by introducing sulfur producing genes from sunflower into clover grass. By eating this grass, the sulfur deficiency of the sheep was compensated and the wool quality of the sheep was improved.
(ii) Transgenic animals are created through biotechnology. Medicines are made from milk, blood and urine of transgenic animals.
(iii) Deficiency of lactoferrin enzyme causes mastitis in cow’s udder and reduced milk production. Transgenic bulls are created by injecting lactoferrin into bulls. The progeny of these transgenic bulls are resistant to mastitis.
(iv) Genes for human growth hormone have been introduced into sheep to produce more growth-prone sheep.
(v) High-growth fish have been developed by introducing marine fish genes into salmon, trout and pomace. The growth of salmon increased by 30 times.
(vi) Increased milk production by administration of bovine somatotropin to cows.

The flavor saver tomato (CGN-89564-2) was created by collecting the PG gene from the militant tomato (Lycopersicon escolentum) and inserting it into the modern tomato (Lycopersicon lycopersicum). The taste and smell of this tomato is improved. It ripens late, does not rot easily and can be stored for a long time. Besides, the British Zenica tomato was invented.

Golden or golden colored rice is called golden or super rice. In 2000, Swiss Federal Institute of Technology scientist Ingo Potrykus and German Freiburg University scientist Peter Beyer jointly invented golden rice. They created super rice by introducing four beta carotene producing psy (phytoene synthase) genes from daffodil plant, three iron producing genes and crtI (carotene desaturase) gene from Erwinia uredovora bacteria into Japonica rice. Eating this rice does not cause night blindness. Apart from this, there is no anemia in the mother’s body. In 2005, Golden Rice-2 was developed which provides 23 times more beta-carotene. Young boys and girls in various countries of Asia, Africa and Latin America, including Bangladesh, are deficient in vitamin A. Vitamin A deficiency causes night blindness.

(i) Transgenic cotton plants have been created by introducing a gene from Bacillus bacteria into American cotton plants. These transgenic cotton plants produce a toxic protein. Due to this, insect attack does not occur. As a result cotton production increased. Along with this, production costs are reduced and environmental pollution is prevented.
(ii) At present insect resistant plants like potato, apple, cotton, wheat etc. have been developed. Bt toxin gene and CpTi gene have been inserted in these plants. Insects die within 24 hours after eating the leaves of these plants.
(iii) USA company has produced caterpillar resistant cotton seeds. As a result, pest problems in cotton cultivation have been eliminated.
(iv) Cry gene isolated from Bacillus thuringiensis bacteria and introduced into plants to create insect resistant plants. Transgenic plants like Bt brinjal, Bt cotton, Bt rice, Bt corn, Bt potato, Bt apple are resistant to pests.
(v) Larvae attack of European cornbora moth causes extensive damage to bhutra and yield reduction of 40%. Transgenic bhutra has been created by introducing genes from bacteria that produce toxic proteins into bhutra plants. This bhutra is not affected by cornbora. Now there is no need to apply pesticides in Bhutra cultivation. This has increased the yield of Bhutra, reduced production costs and prevented environmental pollution.
(vi) Rhyzobium was introduced into Rhyzobium with toxin producing gene from Bacillus thuringiensis bacteria. Rhyzobium causes nodules on the roots of legumes. Bean plants with nodules can prevent attacks by harmful insects like weevils.
(vii) Bt toxin gene has been created by introducing the gene from Bacillus thuringiensis bacteria into cotton plant. Insects such as Lepidoptera, beetles, flies, mosquitoes etc. have died by eating cotton plants containing Bt toxin gene.
(viii) Sterile Insect Technique (SIT) is a modern method. It is an environmentally friendly pest control method. Males of harmful insects are sterilized by this method. As a result the new generation does not develop. This technology is being used in countries like Brazil, Japan, Philippines, Thailand, USA etc.

(i) Recombinant DNA is introduced into host Agrobacterium tumefaciens cells. The genes are then inserted into plant cells.
(ii) RNA of TMV with desired genes is introduced into tobacco plants.
Role of recombinant DNA in development of high yielding varieties
High yielding varieties have been created by introducing desired genes from wild species into crop plants. Genes producing beta carotene and iron from daffodil plant have been introduced into rice, wheat, bhutra, soybean, potato, tomato, papaya, rye, sunflower, pear, grape etc. to create high yielding varieties.

(i) Calcium chloride: Cells are first incubated in cold CaCl2 solution and heat-shocked to introduce recombinant DNA into host cells.
(ii) Liposome: Recombinant DNA is first incorporated into artificial vesicles. The vesicle is then attached to the cell membrane. The recombinant DNA is then introduced into the host cell.

Recombinant DNA is first incubated with artificial vesicles. The vesicle is then attached to the cell membrane. The recombinant DNA is then introduced into the host cell.

(i) Electroporation: Pores are created in the host cell membrane by an electric field. Recombinant DNA is introduced into the host cell through this pore.
(ii) Micro-injection: The host cell is held by a micropipette and the recombinant DNA is injected into the host cell by a fine needle.
(iii) Biolistics: Recombinant DNA is placed on the surface of a metal particle (gold) and that particle is gunshotted into the plant cell.

Recombinant DNA is placed on top of a metal particle (gold) and the particle is gunshotted into the plant cell.

The host cell is captured with a micropipette and the recombinant DNA is injected into the host cell with an ultrafine needle.