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Restriction enzyme
Restriction enzyme cut the strand of DNA a little away from the centre of the palindrome sites but between the same two bases on the opposite strands. This leaves single-stranded portions at the ends. There are overhanging stretches called sticky ends. There are overhanging stretches called sticky ends on each strand. There are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase. The word "palindrome" refers to a group of letters that forms the same words when read both forward and backward. Restriction endonucleases are used in genetic engineering as molecular scissors.
1. Overhanging stretches on each strand is called
a)hydrogen bond
b)sticky end
c)ligase
d)palindrome
2. Which one of the following enzymes helps to join DNA?
a)DNA polymerae
b)DNA ligase
c)endonuclease
d)RNA polymerase
3. Which bond forms on sticky end of each strand?
a)Peptide bond
b)sulphide bond
c)hydrogen bond
d)carbon bond
4. Palindromes are
a) the same group of letters, which read both forward and backward
b) the different group of letters when read both forward and backward
c) same group of letters when read only forward
d) same group of letters when read only backward
5. Which of the following option is correct about restriction enzymes?
a) It helps in binding of DNA
b) This is known as molecular scissors
c) It has ability to multiple copies of plasmid
d) It helps in transfer of piece of DNA
Answers:
1. b)sticky end
2. b)DNA ligase
3.c)hydrogen bond
4. a) the same group of letters, which read both forward and backward
5. b) This is known as molecular scissors