5

noun1

1. •
   Clipping of 540 (“540° spin”).

adjective1

1. •
   Relatively close to the 5′ end of a strand of DNA.

   • A CG pair is often designated CpG to signify that the two nucleotides are contiguous in DNA and that the C is 5′ to the G. — 1992

noun1

1. •
   That end of any DNA strand that has a terminal phosphate group.