Chapter 11-BIOTECHNOLOGY- PRINCIPLES AND PROCESSES
BIO XII 4.1.1
Q. 1.Which enzymes are called molecular scissors?
Q. 2.What do you mean by Ori?
Q. 3.Name the polymerase which is generally used in PCR reactions.
Q. 4.How is a host cell made competent in introducing rDNA?
Q. 5.Name the enzyme commonly used to dissolve the cell wall of bacterial cell?
ANSWERS
Ans. 1.Restriction Endonucleases
Ans. 2.Ori is short form of origin of replication. This is the sequence from which replication starts
Ans. 3.Taq polymerase
Ans. 4. The host cell is first treated with a specific concentration of a divalent cation like calcium. It increases the efficiency with which DNA enters the bacterium through pores in the cell wall. rDNA is forced into the cells by incubating them with rDNA on ice’
Ans. 5. lysozyme
BIO XII 4.1.2
Q. 1.Why is a thermo stable DNA Polymerase needed in amplification/genetic engineering.
Q. 2.For the isolation of the genetic material , cells are treated with cellulose or chitinase . Give reason for it
Q. 3.Name the enzyme which cut the DNA molecules into fragments with sticky ends?
Q. 4.Which cloning vector was discovered first time?
Q. 5.Name the method in which foreign DNA is directly introduced into host cell?
Q. 6.Name a ‘Natural genetic engineer’ of plants?
Q. 7.What are the three basic steps involved in a single PCR amplification cycle.
Q. 8.Draw the diagram of PBR322 vector showing restrictions site
Q. 9.How is isolation of the genetic material done?
Q. 10.Give diagrammatic representation of rDNA technology
ANSWERS
Ans. 1. Thermostable DNA polymerase remains active during high temperature.It is used to denature the double stranded DNA
Ans. 2. These are used to break the cell wall of the plant cell or that of fungus to release the DNA .
Ans. 3. Restriction endonucleases
Ans. 4. Cloning vector pBR322
Ans. 5. Microinjection
Ans. 6. Agrobacterium tumefaciens
Ans. 7. Three basic steps are denaturation, annealing and extension.
Ans. 8.See & Draw NCERT Text Book page -199 fig 11.4
Ans. 9.It is separated by a technique called gel electrophoresis’
The DNA is cut into fragments by restriction endonucleases
The fragments are separated by gel electrophoresis using agarose as matrix.
Ans. 10. See & Draw NCERT Text Book page 197 fig 11.2.
BIO XII 4.1.3
Q. 1.“Normal Polymerase can not be used in PCR.A particular polymerase is used in PCR.”Name the source of that polymerase.
Q. 2. Each restriction enzyme cuts the DNA at a specific nucleotide sequence. Name such a sequence.
Q. 3.What type of cut ends are formed when both stands of DNA molecule are cleaved exactly at the same nucleotide position?
Q. 4.How does a transgenic organism differ from the rest of its population? Cite any two examples of such organism for human advantage
Q. 5.How is the gene z (for B-galactosidase) used as marker?
Q. 6.Besides better aeration and mixing properties what other advantages do stirred tank bioreactors have over shake flasks ?
Q. 7.How are bacteria made capable to take up recombinant DNA? Name the bacteria used for this process.
Q. 8.State the principle underlying ‘gel electrphoresis’ and mention two applications of this technique in Biotechnology.
Q. 9.DNA being hydrophilic cannot pass through the cell membrane of a cell. Explain how does recombination DNA get introduced into the cell to transform the latter.
Q. 10.In bacterial culture some of the colonies produce blue colour in the presence of a chromogenic substrate and some did not due to the presence or absence of an insert (rDNA) in the coding sequence of the beta-galactosidase.
a) Mention the mechanism and steps involved in the above experiments .
b) How is it better than the technique of plating on two plates having different antibiotics?
ANSWERS
Ans. 1. Thermus aquaticus bacteria .
Ans. 2. Palindromic sequence
Ans. 3. Blunt end
Ans. 4.A transgenic organism is a GMO that carries certain foreign genes. Examples. [a]transgenic mouse with gene for human growth hormone.
[b]transgenic E. coli with gene for human insulin.
Ans. 5. Recombinant DNA is inserted within the coding sequence of B galactosidase which results in the inactivation of the enzyme’
Ans. 6. Foam control system , a temperature control system , pH control system and sampling port to take small volume of culture periodically are the advantages of the stirred tank bioreactors .
Ans21:-NCERT T.B. page -199 fig 11.4
Ans. 7. By treating bacteria with calcium chloride or lysozyme; E.coli and Bacillus subtilis
Ans. 8. a) technique where charged molecules are separated on their molecular weight. The gel acts as a sieve.
b) DNA fingerprinting, cloning DNA
Ans. 9.Electroporation: Bacterial cells are treated with Ca++, given a heat shock, DNA enters through pores in the cell wall
Microinjection: Recombinant DNA is directly Microinjected
Biolistic or Gene Gun Method: Bombardment by high velocity microparticles of gold/tungsten collated with DNA by gene gun.
Ans.10. - a) Insertion of foreign DNA in gene Zcoding for enzyme Beta galactosidase inactivates it and prevents synthesis of Beta- galactosidase .Plasmids with inserts or cloning vectors are added over cultures of plasmid free bacteria and colonies are raised .Chromogenic substrate is poured over the colonies after some time . Presence of recombinant plasmid is indicated by white colonies whereas colonies are blue coloured if plasmids do not have inserts .
a) Plating on two plates having different antibiotics requires the presence of antibiotic resistance genes in the plasmid, one for the insert and the other for eliminating non-transformed bacteria . Enzymes produced by such plasmids can harm human system and antibiotic resistance genes can pass into the genome of the bacteria and then to the pathogenic bacteria making them drug resistant .
