question_answer

  (a) What is the structural difference between a nucleotide and nucleotide?                                                                        (b) Two strands of DNA are not identical but complementory. Explain?                                                                 

Answer:

                  (a) Difference between Nucleotide and Nucleoside                

When the phosphate group is attached to the nuceloside, the compound formed is called nucleotide.

The molecules in which one of the nitrogen base (Purine or pyrimidine) is bounded with a sugar molecule is called nucleoside.

  (b) The two strands of the DNA molecules are said to be complementary to each other in the sense that the sequence of bases in one strand automatically controls that of the other. This specific base pairing is the most important principle of the structure of DNA.                                                                                                                       1