Question
Biology Question on biotechnology
Bacteria protect themselves from viruses by fragmenting viral DNA upon entry with
A
methylase
B
endonuclease
C
ligases
D
exonucleases
Answer
endonuclease
Explanation
Solution
Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease-I, cut DNA relatively non-specifically (without regard to sequence), while many, typically called restriction endonuclease or restriction enzyme, cleave only at very specific nucleotide sequences.