Sticky and blunt ends

DNA ends refer to the properties of the end of DNA molecules, which may be sticky or blunt based on the enzyme which cuts the DNA. The restriction enzyme belong to a larger class of enzymes called exonucleases and endonucleases. Exonucleases remove nucleotide from ends whereas endonuclease cuts at specific position within the DNA. DNA ends refer to the properties of the end of DNA molecules, which may be sticky or blunt based on the enzyme which cuts the DNA. The restriction enzyme belong to a larger class of enzymes called exonucleases and endonucleases. Exonucleases remove nucleotide from ends whereas endonuclease cuts at specific position within the DNA. The concept is used in molecular biology, especially in cloning or when subcloning inserts DNA into vector DNA. Such ends may be generated by restriction enzymes that cut the DNA – a staggered cut generates two sticky ends, while a straight cut generates blunt ends. A single-stranded non-circular DNA molecule has two non-identical ends, the 3' end and the 5' end (usually pronounced 'three prime end' and 'five prime end'). The numbers refer to the numbering of carbon atoms in the deoxyribose, which is a sugar forming an important part of the backbone of the DNA molecule. In the backbone of DNA the 5' carbon of one deoxyribose is linked to the 3' carbon of another by a phosphate group. The 5' carbon of this deoxyribose is again linked to the 3' carbon of the next, and so forth.