Question

Molecular scissors, which cut DNA at specific sites are known as __________.

• A. DNA polymerases
• B. DNA ligases
• C. RNA polymerases
• D. restriction enzymes

Answer 1

The correct option is D restriction enzymes

Nucleases are enzymes that hydrolyse the phosphodiester bonds of DNA and RNA.

Restriction enzymes are a type of nucleases. Restriction enzymes are called molecular scissors as they cleave DNA at or close to specific recognition sequences known as restriction sites. These enzymes make a single incision on each of the two DNA strands to generate restriction fragments. These enzymes are also called restriction endonucleases.

DNA-dependent DNA polymerases are enzymes that synthesise DNA using a DNA template.

RNA-dependent DNA polymerases are enzymes that synthesise DNA using an RNA template.

RNA polymerase is an RNA synthesising enzyme that transcribes DNA into RNA.

Ligases are enzymes that are capable of catalysing the reaction of joining two large molecules by establishing a new chemical bond.

DNA ligase catalyses the joining of the 3′-OH of one nucleotide with the 5′-phosphate of the consecutive nucleotide by means of a phosphodiester bond.