12th Class Biology Chapter 9 Biotechnology Short Questions Answer
1.What is the use of genetically engineered bacteria?
Genetically engineered becteria have been used to clean up environmental pollutants increase the fertility of soil and kill insect pests.
2.What are teh restriction enzymes?
There are natural enzymes of bacteria which they use for their own protection against viruses.They are called restriction enzymes because thy restricy the growth of enzyme.
3.Why transgenic animals are cloned?
Transgenic animals are cloned in order to obtain the product in large quantity.
4.Which enzyme is Taq polymerase?
DNA polymerase used is temperature-insensitive extracted from the bacterium thermus aquaticus which lives in hot springs.Commonly this enzyme is also known as Taq polymerase.
5.How transgenic animals are developed?
Techniques have been developed to insert genes into the eggs of animals.It is possible to micro inject foreign genes into eggs by hand but another method uses vortex mixing.The eggs are placed in an agitator with DNA and silicon-carbide needles,and the needles make tiny holes through which the DNA can enter.When these eggs are fertilized the resulting offsprings are transgenic animals.
6.From which amimal antithrombin III is produced?
Antithrobin III for preventing blood clot during surgery is currently being produced by a gerd of goats and clinical trials have begun.
7.How many methods are used for gene therapy?Name them.
There are two main metnods used for gene therapy: i) Ex-vivo ii)in-vivo
8.How transgenic animals that secrete a product are often cloned?
After enucleated eggs have been injected with 2n nuclei of adult cells they can be coaxed to begin development.The offspring have the genotype and phenotype of the adult that donated the nuclei therefore the adult has been cloned.
9.What is Dolly?
In 1997 scientists at the Roslin Insitute in Scotland produced a cloned sheep called Dolly.
10.When recombinant DNA technology is used and when PCR?
Recombinant DNA technology is used when a very large quantity of a gene is required.The polymerase chain reaction is used to create a lesser number of copies within a laboratory test tube.
11.How genes can be isolated from chromosomes?
Genes can be isolated from the chromosomes by cutting the chromosomes on the flanking sites of the gene using special enzmes known as restriction endonucleases.
12.What is complementary DNA?
The gene of choice can also be synthesized in the laboratory from massenger RNA using reverse transcriptase.This DNA molecule is called complementary DNA.
13.What are Palindromic Sequences?
Bacteria produces a variety of such restriction enzymes which cut the DNA at very specitic sites characterized by specific sequence of four to six nucleotides arranged symmetrically in the reverse order.Such sequences are known as palindromic sequences.
14.What are sticky ends?
The single stranded but complementary ends of the two DNA molecules are called sticky ends because they can bind by complementary base pairing.
15.What is vector?
A vector is the means by which recombinant DNA is introduced into a host cell.One common type of vector is a plasmid.
16.What are plasmids?
Plasmids are natural extra chromosomal circular DNA molecules which carry genes for antibiotic resistance and fertility etc.One of the plasmids discovered earlier PSC 101 has antibiotic resistance gene for tetracycline whereas PSR 322 has antibiotic resistance genes for tetracycline as well as ampicillin.
17.What is the use of DNA or chimaeric DNA?
The gene of interest is then joined with the sticky ends produced after cutting the plasmid with the help of another special enzyme known as DNA ligase.This enzyme seals the foreign piece of DNA into the vector.
18.What is recombinant DNA or chimaeric DNA?
When the two different pieces of DNA have been joined together it is known as recombinant DNA or chimaeric DNA.
19.What is clone?
A clone can be a large number of molecules or cell or organisms that are identical to an original specimen.
20.What is a genome and genomic library?
A genome is a full set of genes of an individual.A genomic library is a collection of bacterial or bacteriophage clones each clone containing a particular segment of DNA from the source cell.
21.What is a probe?
A probe is a single stranded nucleotide sequence that will hybridize into a certain piece of DNA.
22.What is the polymerase chain reaction of PCR?
The PCR is used to create millions of copies of a single gene or any specific piece of DNA quickly in a test tube.Kary B.Mullis developed the polymerasew chain reaction in 1983.
23.Where from PCR took its name?Why is callled chain reaction?
PCR takes its name from DNA polymerase the enzyme that carries out DNA replication in a cell.It is considered a chain reaction because DNA polymerase will carry out replication over and over again.until there are millions of copies of the desired DNA.
24.What is DNA Finger printing?
DNA Finger printing is a method of identification that compares fragments of deoxyribonucleic acid DNA.
25.What is gel electrophoresis?
It is the process by which the fragments of DNA can be separated according to their lengths and the result is a number of bands that are so close together that they appear as a smear.However the use of probes for genetic markers produces a distinctive pattern that can be recorded on X-ray film.
26.What is gene sequencing?
In DNA or gene sequencing scientists create many copies of a single-stranded DNA fragment that will be used to synthesize a new DNA strand.Then these will be used to determine sequence of nucleotides.
27.What are various methods of gene or DNA sequencing?
1) Snager method 2) Maxam-Gilbert method
28.What is Sanger’s method?
In this method dideoxy ribonucleoside are used to terminate into DNA synthesis at different sites.
29.What is Maxam-Gilbert method?
In this method DNA threads are chemically cut into pieces of different sizes.
30.What is the use of dideoxy method?
In order to separate DNA pieces of different sizes on gel dideoxy method is used.
31.Name different organisms and organelles whose genomes have been sequenced?
It includes plant chloroplasts and animal mitochondria large numbers of bacteria many of the yeasts a nematode worm Drosophila the model plant Arabidopsis the mouse and human.
32.What is the purpose of primary goal of human genome project?
The human genome project is massive effort to map the human chromosomes.The genes along the length of each type of chromosome are sequenced and then base pairs are found.
33.What are biotechnology products?
The products produced by genetically engineered organisms are called biotechnology products.Today bacteria plants and animals are genetically engineered to produce biotechnology products.
34.What are transgenic organisms(animals or plants)?
Organisms that have had a foreign gene inserted into them are called transgenic organisms.
35.What are bioreactors?
Bioreactors are large vats in which bacteria reproduce when recombinant DNA technology is used to produce them.
36.Name some biotechnology products produced by bacteria?
Biotechnology products produced by bacteria such as insulin human growth hormone tissue plasminogen activator haemophilia factor VIII,and hepatitis B vaccine are now in the market.
37.What are Biofilters?
The transgenic organisms used to prevent airborne chemical pollutants from being released into the air are said to be biofilters.For example use of such bacteria in industry.
38.What are protoplasts?
The plant cells that have had the cell wall removed are called protoplasts.
39.Give two advantages of transgenic plants?
i) Resistant to pests and herbicides. ii)Improvement of dietary contents.
40.Give two advantages of transgenic animals?
i) Bovine growth hormone. ii) Producing larger animals.
41.Define gene therapy?
Gene therapy is the insertion of genetic material into human cells for the treatment of a disorder.
42.What is Ex-vivo gene therapy?
In ex-vivo gene therapy normal gene is give to certain cells of the patient outside the body of the patient and then these cells are returned to the patient.
43.What is the method of ex-vivo gene therapy?
Bone marrow stem cells are removed from the blood and infected with a retrovirus that carries a normal gene for the enzyme then the cells are returned to the patient.
44.What is in-vivo gene therapy?
In in-vivo gene patients are directly given normal genes in one way or the other.
45.What is familial hypercholesterolemia?
It is a condition that develops when liver cells lack a receptor for removing cholesterol from the blood.The high levels of blood cholesterol make the patient subject to fatal heartl attacks at a young age.
46.What is Cystic fibrosis?
Cystic fibrosis patients lack a gene that codes for trans-memrane carrier of the chloride ion.Patients often die due to numerous infections of the respiratory tract.
47.How gene therapy has been used for the treatment of cancer?
In clinical trials researchers have given genes to cancer patient that either make healthy cells more tolerant of chemotherapy or make tumours more vulnerable to it.Once the bone marrow stem cells were protected it was possible to increase the level of chemotherapy to kill the cancer cells.
48.How gene therapy has been used for the treatment of coronary artery angioplasty?
The balloon catheter is coated with a plasmid that contains a gene for vascular endothelial growth factor.The expression of the gene which promotes the proliferation of blood vessels to bypass the obstructed area has been observed in at least one patient.
49.What is tissue culture?
Tissue culture is the growth of a tissue in an artificial liquid culture medium.
50.plant cells are said to be totipotent.What do you mean by this?
Plant cells are totipotent which means that each cell has the full genetic potential of the organism and terefore a single cell could become a complete plant.
Name the enzyme which helps synthesize desirable gene in the laboratory, form mRNA.
The name of the enzyme is reverse transcriptase.
Explain restriction enzyme (restriction endonuclease)?
It is an enzyme that binds to specific short sequences of four to six nucleotides of DNA and cuts the DNA at or near this point. Such enzymes are produced by certain bacteria in response to invasion by bacteriophage. They destroy the virus by cutting up its DNA.
What do you mean by palindromic (repeated) sequences?
These are the sequences of base pairs of the nucleotides repeated at many different places throughout the chromosomes.
What are vectors?
Vectors are the carrier molecules which are used to introduce the recombinant DNA into the host cells, in genetic engineering.
The plasmids are extra chromosomal circular DNA molecules found in bacteria which are common vectors being used in recombinant DNA technology. They themselves carry genes for antibiotic resistance and fertility etc.
Which resistance genes are carried by the plasmids pSC 101 pBR 322?
pSC 101 has antibiotic resistance gene for tetracycline whereas pBR 322 has antibiotic resistance genes for tetracycline as well as ampicillin.
What is the role of restriction enzyme in the preparation of recombinant DNA during genetic engineering?
The restriction enzyme cuts open the plasmid ring for the preparation of recombinant DNA during genetic engineering.
How is the enzyme, DNA ligase used in genetic engineering?
The DNA ligase serves to attach desired genes to the sticky ends (open ends) of the plasmid ring, thus closing it again.
What is recombinant DNA and its technology in genetic engineering?
The vector along with the attached foreign genes is known as recombinant DNA and the technique for such attachment is called as recombinant DNA technology.
What is another name for recombinant DNA?
It is Chimeric DNA.
What can be used as vector, other than the plasmid?
The DNA of the bacteriophages (lambda phage) can also be used as a vector.
What does genome mean?
The total number of different genes found within the cell of an individual is called its genome (or genetic material or hereditary material).
Describe genomic library.
The genomic library is a collection of bacterial of bacteriophage clones, each of which contains a particular segment of DNA from the donor cell.
What is totipotency?
Totipotency is the capacity of an isolated cell to form a complete plant because it has the full genetic potential of the organism.
Who and when said that the plant cells are totipotent?
A German botanist, Gottleib Haber land said in 1902 that the plant cells are totipotent.
Who and when grew a whole carrot plat from a tiny piece of phloem?
A botanist, F.C. Steward grew a complete carrot plant from a tiny piece of phloem in 1958.
Which plant hormone is contained in the coconut milk?
It is the cytokinin.
What is a protoplast?
The protoplast is the plant cell without cell wall.
Explain cell suspension culture?
It is the system of growing single cells or small clumps of cells in a liquid growth medium that is kept agitated by means of bubbling, shaking of stirring so that the cells do not settle out.
Which chemicals are obtained from cell suspension cultures of Cinchona ledger Lana and Digitalis lanata?
These are respectively the quinine and digitoxin.
Give definition of hybridization?
The crossing of different varieties (or even species) to produce plants with desirable traits is called hybridization.
Differentiate between Lucifer in and Luciferase?
The Lucifer in is a protein-like substance found in the luminous organs of certain animals like firefly Luciferase is the enzyme that contributes to light production from the Lucifer in.
Explain familial hypercholesterolemia?
It is a condition of having excessive cholesterol in the blood in certain families that is caused when liver cells lack a receptor for removing cholesterol from the blood.
How can hypercholesterolemia be controlled by gene therapy?
A small portion of the liver is surgically excised (cut) and is infected with a retrovirus containing a normal gene for the receptor needed to remove cholesterol from the blood.
What is cystic fibrosis?
Cystic fibrosis is a fatal genetic disease that is characterized by secretion of thick mucus that blocks passages in the lungs, liver and pancreas.
The plastic surgery of blood vessels is known as angioplasty.
Give examples of ex-vivo and in-vivo gene therapies in man?
The examples of ex-vivo gene therapies in man are the severe combined immunodeficiency syndrome, hypercholesterolemia, cystic fibrosis, cancer and coronary artery angioplasty whereas those of in-vivo therapies are hemophilia, diabetes, Parkinson’s disease and AIDS.
How can Parkinson’s disease be cured by gene therapy?
It can be cured by grafting dopamine-producing cells directly into the patients brain.
Define tissue culture?
Tissue culture is the growth of a tissue in an artificial liquid growth medium.
How can the useful (desirable) genes be obtained for producing recombinant DNA?
The desirable genes can be isolated from the chromosome or synthesized chemically or made from messenger RNA.
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