a1.2.11 - directionality of RNA and DNA

Question 1

identify and label the 5’ and 3’ ends on a DNA or RNA diagram.

Answer 1

• each end of DNA nucleotide has a number. one end is referred to as 5’ (five prime) and the other end is referred to as 3’ (three prime). the 5’ and 3’ designations refer to the number of the carbon atom in a deoxyribose sugar molecule. the 5’ end is identified by the presence of the phosphate group and the 3’ end is identified as ending in the pentose sugar (ribose or deoxyribose).
• in DNA, one strand will run from 5’ to 3’ and the complementary strand will run anti-parallel, from 3’ to 5’.