Question

Explain briefly
1. PCR
2. Restriction enzymes and DNA
3. Chitinase​

Answer 1

Answer:

(i) PCR: PCR stands for polymerase Chain Reaction. In this reaction multiple copies of the gene ( or DNA ) of interest is synthesised vitro in, using sets of primers and the enzyme Taq DNA Polymerase. (ii) Restriction Enzymes and DNA: these are the enzymes which restrict the growth of bacteriophages.Solution

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(a) PCR - Polymerase chain reaction technique amplify the DNA from one copy to more than one in three steps namely denaturation of target DNA (thermal cycle to separate the DNA strands), annealing of primers to the ssDNA and polymerization (extension of primer into complete DNA strand complementary to the template strand).

(b) Restriction enzymes recognize specific sequences, mostly 4-6 bp, in the DNA and cut it into fragments by breaking the phosphodiester linkage between two successive nucleotides of DNA. DNA is polymer of deoxyribonucleotides and serves as genetic material

(c) Chitinases are class of enzymes that can digest chitin; the major component of fungal cell wall

Answer 2

PCR

• Abbreviation : Polymerase chain reaction.

• It is a laboratory technique used to make multiple copies of a segment of DNA.

• The steps are Denaturation, Annealing, Extension and Analysis with electrophoresis.

Restriction enzymes and DNA

• It is a DNA-cutting enzyme that recognizes specific sites in DNA.

• If two DNA molecules have matching ends then they can be joined by enzyme DNA ligase which seals the gap between the molecules by forming a single piece of DNA.

• It restricts the growth of bacteriophages.

Chitinase​

• It is a class of enzymes used for the degradation of chitin.

• It forms a major component of the fungal cell wall.

• It have been isolated from the stomachs of mammals, including humans.