This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
Function of Endonucleases 
Select and explain. 
A. Enhancers, B. To point out the coding regions, C. To find out antibiotic resistance, D. Cut DNA at specific DNA sequences
D: Cut DNA at specific DNA sequences
Answer: D: Cut DNA at specific DNA sequences 
Explanation: (D) Cut DNA at specific DNA sequences # Restriction enzymes(endonucleases) are bacterial proteins that recognize specific DNA sequences and cut DNA at or near the recognition site. These enzymes are widely used in molecular genetics for analyzing DNA and creating recombinant DNA molecules. The ability of restriction enzymes to reproducibly cut DNA at specific sequences has led to the widespread use of these tools in many molecular genetics techniques. Restriction enzymes can be used to map DNA fragments or genomes. Mapping means determining the order of the restriction enzyme sites in the genome. These maps form a foundation for much other genetic analysis. Restriction enzymes are also frequently used to verify the identity of a specific DNA fragment, based on the known restriction enzyme sites that it contains.