The term molecular scissors refers to Restriction enzymes.

Explanation:
Restriction enzymes, also known as restriction endonucleases, are enzymes that can recognize specific DNA sequences and cleave the DNA at those sequences. These enzymes act as "molecular scissors" by cutting the DNA into smaller fragments.

Function of Restriction Enzymes:
Restriction enzymes are naturally occurring enzymes found in bacteria and archaea. They play a crucial role in the defense mechanisms of these organisms by cutting foreign DNA, such as viral DNA, at specific recognition sites. This helps protect the organism from invasion by foreign genetic material.

Recognition Sites:
Restriction enzymes recognize specific DNA sequences called recognition sites or restriction sites. These recognition sites are usually palindromic, meaning they read the same forward and backward on complementary DNA strands. For example, the recognition site for the restriction enzyme EcoRI is 5'-GAATTC-3', which is palindromic.

Cutting the DNA:
Once the restriction enzyme recognizes its specific recognition site, it binds to the DNA at that site and makes a double-stranded cut. The cut can be blunt or staggered, depending on the type of restriction enzyme. Some enzymes create overhangs known as sticky ends, while others create blunt ends.

Applications:
Restriction enzymes are widely used in molecular biology and biotechnology. Their ability to cut DNA at specific sequences allows scientists to manipulate and study DNA in various ways. Some applications of restriction enzymes include:

1. DNA Fragmentation: Restriction enzymes are used to cut DNA into smaller fragments, which can be further analyzed or used in other experiments.
2. DNA Cloning: Restriction enzymes are used to generate compatible ends on DNA fragments and vectors, allowing them to be ligated together during the cloning process.
3. Genetic Engineering: Restriction enzymes are used to insert or remove specific DNA sequences during the process of genetic engineering.
4. DNA Fingerprinting: Restriction enzymes are used in DNA fingerprinting techniques to generate unique DNA fragment patterns for identification purposes.

In summary, the term "molecular scissors" refers to restriction enzymes because they have the ability to recognize specific DNA sequences and cleave the DNA at those sequences. These enzymes play a crucial role in DNA manipulation and various applications in molecular biology and biotechnology.