An enzyme that joins the ends of two strands of nucleic acid is
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Think of DNA Ligase as the molecular "glue" or "sealing tape" that connects DNA fragments, while restriction enzymes act as the molecular "scissors" that cut them.
Step 1: Understanding the Concept:
Molecular biology relies on specific enzymes to manipulate DNA and RNA strands. Joining adjacent nucleotides together requires the formation of a phosphodiester bond. Step 2: Detailed Explanation:
Let us analyze the function of each of the listed enzymes:
Polymerase: DNA or RNA polymerases synthesize new nucleic acid strands by adding free nucleotides to a template strand. They do not join pre-existing independent strands together.
Ligase (DNA Ligase): This enzyme catalyzes the formation of a covalent phosphodiester bond between the 3'-hydroxyl end of one nucleotide and the 5'-phosphate end of another.
It is used to seal nicks in the sugar-phosphate backbone of double-stranded DNA, and is essential for joining Okazaki fragments during DNA replication and connecting DNA fragments in recombinant DNA technology. Thus, this is the correct enzyme.
Synthetase: This is a general class of enzymes that catalyze the synthesis of various molecules, usually utilizing ATP hydrolysis, but it is not specific to joining nucleic acid backbones.
Helicase: This enzyme unwinds the double-stranded DNA helix by breaking the hydrogen bonds between complementary base pairs ahead of the replication fork.
Therefore, the enzyme that joins the ends of two nucleic acid strands is ligase. Step 2: Final Answer:
The correct option is (B).
