Question
Biology Question on biotechnology
Restriction endonucleases
are present in mammalian cells for degradation of DNA when the cell dies
are used in genetic engineering for ligating two DNA molecules
are used for in vitro DNA synthesis
are synthesized by bacteria as part of their defense mechanism.
are synthesized by bacteria as part of their defense mechanism.
Solution
Restriction endonucleasses are enzymes that digest double stranded DNA following recognition of specific nucleotide sequences. This is achieved by cleaving the two phosphodiester bonds, one within each strand of the DNA duplex. They are found in bacteria and their function in bacteria is to cut up any invading virus as a part of its defense mechanism, thus restricting the multiplication of viruses in the bacterial cell. Different species of bacteria produce different restriction endonucleases.