The Eco RI restriction enzyme identifies and cleaves the provided sequence. Based on the cut pattern, what types of bonds are cleaved by the action of the enzyme?
A. Covalent bonds between the sugar and nitrogenous base
B. Covalent bonds within the nitrogenous base
C. Covalent bonds between the sugar and phosphate groups
D. Hydrogen bonds between the sugar and phosphate
VerifiedHint: Consider the structure of DNA and the mechanism of restriction enzymes.
Complete step-by-step Answer: Eco RI is a restriction enzyme that recognizes and cleaves the following DNA sequence:
5'-GAATTC-3'
Eco RI cuts the DNA molecule at the phosphodiester bond between the sugar and phosphate groups of the G and A nucleotides.
Restriction enzymes are a type of enzyme that recognizes and cleaves specific DNA sequences. They are used in molecular biology to cut DNA molecules into smaller pieces, which can then be manipulated and analyzed.
Restriction enzymes are essential for many molecular biology techniques, including cloning, sequencing, and gene editing.
Further Explanation: DNA is a double-stranded molecule composed of four nucleotides: adenine (A), guanine (G), cytosine (C), and thymine (T). Each nucleotide consists of a sugar molecule, a phosphate group, and a nitrogenous base.
The sugar and phosphate groups form the backbone of the DNA molecule, while the nitrogenous bases are paired with each other to form the double helix.
Restriction enzymes recognize specific DNA sequences and cleave the phosphodiester bond between the sugar and phosphate groups of two nucleotides. This cleavage produces two DNA fragments with sticky ends, which are complementary to each other.
Sticky ends can be used to join DNA fragments together, which is a key step in many molecular biology techniques, such as cloning and gene editing.
Eco RI is one of the most widely used restriction enzymes. It is used in a variety of molecular biology techniques, including cloning, sequencing, and gene editing.
Here is a diagram of the Eco RI restriction site and the cleavage pattern:
5'-GAATTC-3'
Eco RI
5'-G|AATTC-3'
3'-CTTAA|G-5'
As you can see, Eco RI cleaves the DNA molecule at the phosphodiester bond between the sugar and phosphate groups of the G and A nucleotides. This produces two DNA fragments with sticky ends, which are complementary to each other.
The sticky ends of the two DNA fragments can then be joined together using DNA ligase, which is an enzyme that catalyzes the formation of phosphodiester bonds.
The incorrect options:
(A) Covalent bonds between the sugar and nitrogenous base: Restriction enzymes do not cleave covalent bonds between the sugar and nitrogenous base.
(B) Covalent bonds within nitrogenous bases: There are no covalent bonds within nitrogenous bases. Nitrogenous bases are held together by hydrogen bonds.
(D) Hydrogen bonds between the sugar and phosphate: Restriction enzymes cleave covalent bonds between the sugar and phosphate groups, not hydrogen bonds.
Hence the correct answer is Option C
Note: Restriction enzymes cleave DNA at the phosphodiester bond between the sugar and phosphate groups. This produces two DNA fragments with sticky ends, which can be joined together using DNA ligase.
