Restriction endonuclease These are specific enzymes, which recognise specific sequence called, recognition sequence of DNA and make double-stranded cuts either within the recognition sequence or at ajvariable distance from the recognition sequence. They.act as scissors and therefore, often are referred to as molecular scissors. The point at which these enzymes cleave the DNA strand is known as restriction site. There will be as many restriction sites as the number of recognition sites. The REs that are used in the recombinant DNA technology fall under class-ll. These make double-stranded symmetrica! cuts within recognition sequence, generating cohesive or blunt ends. These sequences are usually 4-8 base pair long and are palindromic in nature. A palindromic sequence is a nucleic acid sequence that is same wheather read from 5 `rarr` 3 end on one strand or 5 `rarr` 3 T end on complementary strand, e.g 5—GAATTC—3 3—CTTAAG—5 Example Hind\W~Haemophilus influenzae Bam HI - Bacillus amyloliquefaciens
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Read the given statements and select the correct option, Statement 1 : Restriction endonuclease enzymes recognise a specific palindromic nucleotide sequence in the DNA Statement 2: Restriction endonuclease enzymes are called as molecular scissors or biological scissors.
During insertional inactivation, the presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. The blue colour is produced by the enzyme 1) α -glucosidase 2) restriction endonuclease 3) β -galactosidase 4) Taq polymerase
Read the following statements and select the correct ones. (i) Same kind of sticky ends are produced when a DNA has been cut by different restriction enzymes. (ii) Exonucleases make cuts at specific positions within the DNA. (iii) Hind ll was the first restriction endonuclease to be isolated. (iv) A bacteriophage has the ability to replicate within bacterial cells by integrating its DNA with bacterial DNA. (v) Presence of more than one recognition sites for a enzyme within the vector facilitates the gene cloning.
Match the scientists in column I with their related discoveries in column II and select the correct option from the given codes. {:(ColumnI, Column II),(A."Kary Mullis",(i)"Father of genetic engineering"),(B."Paul Berg",(ii)"Nobel prize for the discovery of restriction endonucleases"),(C."Stanley Cohen and Herbert Boyer",(iii)"Developed polymerase chain reaction"),(D."Arber smith and Nathan",(iv)"Isolated an antibiotic resistance gene from a plasmid of the bacterium Salmonella typhimurium"):}
How does a restriction nuclease function ? Explain.
Type-II Restriction enzymes cleave DNA fragments at which site
Restriction enzymes are used to cut single-stranded DNA.
Assertion : Restriction enzymes recongise palindromic sequences. Reason : Palindromic sequences read same in both directions of the two strand.
Which of the following statements does not hold true for restriction enzyme? (a) It recongnises a palindromic nucleotide sequence (b) It is an endonuclease. (c) It is isolated from viruses (d) It produces the same kind of sticky ends in different DNA molecules
ARIHANT PUBLICATION-SAMPLE PAPER 2-SECTION B(ZOOLOGY) (GROUP III) (SHORT NOTE)
