Chapter – 9
Q.1. What is genetic engineering?
Ans. It is the changes in the genetic material of organism made in laboratories for obtaining desirable effects. Genetc engineering usually utilizes bacterial cells and their pasmids. Genetic engineering produces cells containing foreign genes. These cells are capable of producing new and different proteins.
Q.2. What are the steps o recombinant DNA technology? Give names only.
Ans. This technology has following steps
1. Preparation of Recombination DNA (rDNA)
- Restriction Enzyme
- DNA Ligase Enzyme
2. Insertion of DNA into Host Cell
3. Multiplication of Host rDNA
Q.3. What is vector? What is its significance?
Ans. It is the DDNA molecule into which the genne is inserted to construct an rDNA molecule. It acts as a vehicle to transport rDNA into the host cell, which is usually a bacterium. Two common vectors are used in this technique are plasmid or bacteriophage.
Q.4. What are plasmids? What is their use in biotechnology?
Ans. Plasmids are small extra chromosomal circular molecule o DNA found in some bacteria. It can replicate independent of the host chromosome. Plasmids are source of inserting a foreign gene into them. Host cell take up this rDNA as vector and there after bacteria and plasmid reproduce.
Q.5. How a DNA molecule is introduce the foreign gene into the DNA?
Ans. These enzymes are required to cut a source of DNA molecule into small pieces and to cut plasmid to make a gap for foreign gene. These enzymes are naturally found in bacteria. Restriction enzyme cuts DNA at a specific site called sticky ends. The sticky ends of restriction fragments are used in laboratory to join foreign DNA pieces.
Q.6. How cuted DNA molecule is sealed?
Ans. DNA ligase is a key enzyme that seals the restriction fragment with sticky ends of vector.
Q.7. What do you mean by insertion of DNA into the host cell?
Ans. During this technology bacteria are used as host. Bacterial cells take up rDNA when they are treated with calcium chloride to make them more permeable. Some of the bacterial cells will take the desired plasmid DNA from solution.
Q.8. How rDNA molecules are passed into progeny?
Ans. When host cell divides the copies if rDNA molecules are passed into progeny. After a large number of cell divisions a colony of the host cells is produced. Each cell of the colony contains one or more copies of the rDNA molecule.
Q.9. Give some application of biotechnology.
Ans. Application of Genetically Engineered Bacteria
1. In Agriculture – In agriculture, these bacteria promote the health of plant in different ways such as to make them resistant against insects fungi and bacteria. Some bacteria living in root of corn are transformed into insect killing toxins.
2. Oil Eating Bacteria – Some bacteria have ability to degrade some chemicals e.g. oil eating bacteria, which were used to clean up the ol spills at beeches.
3. Insulin Production – Now a days insulin is produced by genetically engineered bacteria. Human growth hormone now synthesized by genetically engineered bacteria.
4. Nutra Sweet – Some genetically engineered bacteria are used to produce phenylalanine, an organic compound to make nutra sweetener called nutra sweet.
5. In Minings – Some genetically engineered bacteria are used by miners to extract copper, uranium and gold from low grade sources.
6. Diagnosis of Disease – Biotechnology also contributes in the diagnosis of genetic diseases.
7. Production of Vaccines – Vaccines are produced from bacteria treated with 8 rDNA technology.
8. Protection of Crops – Cotton, corn, potato and soya bean plants have been engineered to be resistant to either insect predators or herbicides.
9. Enhancing Proof Quality – Biotechnology is also helpful in the enhancement in the food quality of crops.
Q.10. What are transgenic plants?
Ans. Those plants which are genetically engineered are called transgenic plants. Some techniques have been developed to produce transgenic plants. The rDNA can be introduced into embryo or must be in cell wall removed cell called protoplast. The only plasmid transgenic plant is Ti-plasmid, transferred by its host agrobacterium to many but all plants.
Q.11. What are the aims and objects of transgenic plants?
Ans. AIMS OF DEVELOPING TRANSGENIC PLANTS
i. To cultivate more nutritious plants. Protein enhanced beans, soya beans, corn and wheat are now developed.
ii. Plants require less fertilizer and are able to fix nitrogen more efficiently.
iii. Plants grow under harsh and unfavorable conditions. A number of transgenic plants have been developed which resist either insects, viruses. The first transgenic fruit approved retarded spoilage. Plants are being engineered to produce fructose instead of dextrose, human harmones clotting factors and antibodies.
Q.12. What are transgenic animals?
Ans. Genetic engineering of animals has begun. Animal cells do not take plasmids but it is possible to micro insect’s foreign gene into the eggs of various animals before they are fertilized. It had been done of the hope that the gene will establish itself and transmitted to all the cells of the developing organism.
Q.13. What is restriction fragment length polymolphism (RFLPS)? What is DNA finger printing? What are their uses?
Ans. DNA patterns among individual are called restriction fragment length polymorphorism (RFLPs). Since RFLPs of each human is unique, which are used as mark of identity, RFLPs is termed as DNA finger printing. For this purpose DNA drum the samples are cut into fragments are separated in the basis of their sizes. DNA fragments are helpful to settled disputes over parentage. It is also used to identify criminals from blood, semen, saliva etc. left at the site of crime.
Q.14. What is genomic library?
Ans. It consists of copy of genetic information of species in a preferred environment. In order to establish genomic library of particular specie its DNA is cut into fragments by help of restriction enzymes and then fragments are inserted into plasmids and bacteriophage and then into the bacteria. Such bacteria cultured for future use.
Q.15. Into how many categories the genetic diseases can be divided and what are their mode of treatment?
Ans. DETECTION AND TREATMENT OF GENETIC DISEASES
Genetic diseases fall into three categories;
i. Chromosomal – In this condition child born with structurally or numerically abnormal chromosome such as down’s syndrome, Turner’s syndrome and Klinefelter’s syndrome.
ii. Unifactorial Defects – These defects are caused by defective gene or pair of genes e.g. huntingtons disease and cystic fibrosis.
iii. Multifactorial Defects – These defects are caused by additive effects of several genes, along with environmental factors e.g. asthma, diabetes mellitus.
a. Hungtinton’s Disease – It is due to autosomal dominant allele on chromosome number 4. Appearance of symptoms is usually delayed until the age of 40-50 years. This disease is characterized by progressive mental deterioration.
b. Cystic Fibrosis – It occurs due to an autosomal recessive allele. It is characterized by a tendency to chromic lung infection an inability to absorb fats and other nutrients from food.
Q.15. What is gene therapy?
Ans. One of the benefits of genetic engineering is to treat genetic diseases in individual. It could be possible to replace defective gene with a normal gene. This could be done with somatic cells or with germ cells.
Q.16. What is sever combined imuno deficiency disease and how it can be treated? Give its sign and symptoms.
Ans. SEVERE COMBINED IMUNO DEFICIENCY DISEASE (SCID)
This disease is characterized by very poor immune system so the victim cannot resist infections like pneumonia, influenza etc. In this condition the cells of the bone marrow cannot produce an enzyme called adenosine deammase which is important for normal immune response. This diseases treated by the help of gene therapy. In this therapy the defective bone marrow cells of the patient are removed and then insert the normal gene for the ADA enzyme into the bone marrow cells and return the cells into bones of the parient. Now the cells of bone marrow produce ADA enzyme and immune system becomes normal.
Q.17. What is aminocentesis and how it works for the diagnose of diseases?
Ans. It is the diagnostic procedure in which a small amount of amniotic fluid is withdrawn from the amniotic sac. The amniotic fluid contains cells and chemicals from the foetus that can be analyzed to detect fetal abnormalities such as Down’s syndrome, heamophilia. Tay sachs disease etc.
Q.18. What are the disadvantages of biotechnology?
Ans. WORRIES ABOUT BIOTECHNOLOGY
i. Creation of Pathogens – The genetic manipulation of microorganism could create hazardous new pathogens which might escape from lab.
ii. Side Effects of Medical Products – There is a potential for harmful side effects of the medical products.
iii. Introduction of New Organisms – There is also a debate on this burning topic that genetically engineered agricultural products because of potential dangers of introducing new organisms into environment.
iv. New Proteins – There is another worry that food produced by recombinant technology will contain new proteins that may cause severe allergies in some people.
v. Resistance in Plants – Genetically engineered crops could become superweed. Plants resistant to herbicides or microbial disease and pest insects could escape into wild and over grow and will become difficult to control.