Question

What is meant by the term ‘DNA polarity’?

One end of DNA has a 5’ phosphate group while the other end has a free 3’ hydroxyl group.

DNA was first discovered at the North Pole.

One side of DNA has the phosphate backbone while the other side has the nucleotide bases.

There are many polar covalent bonds in DNA.

Answer 1

The one line answer for term ‘DNA polarity’ is that:

One end of DNA has a 5’ phosphate group while the other end has a free 3’ hydroxyl group.

In more detail, DNA (Deoxyribo Nucleic Acid) has an antiparallel double helix structure. Each strand has a 5’ phosphate group (PO4) on one end and free 3’ hydroxyl group (-OH) on the other end. Carbons of the sugar ring in the sugar-phosphate backbone specify the direction (5-prime to 3-prime; 5' to 3') . Polynucleotide chains of DNA are oppositely oriented. Thus, the two strands have opposite chemical polarity with their sugar-phosphate backbones - to which bases are attached - going in opposite directions.  With the result 3' -ends  and 5' -ends of two chains are present in opposite sides. 

One end of DNA has a 5’ phosphate group while the other end has a free 3’ hydroxyl group.