Self Assessment Answer # 1 for Lesson 19 by Dr Jamie Love 2002 - 2005

Phosphate makes the difference!

Any base (A, G, C, T or U) can attach to either sugar (ribose or deoxyribose) to form a "double molecule" called a nucleoside. [But U only to ribose and T only to deoxyribose.]

Phosphate can be attached to the sugar though the 5' carbon to give a "triple molecule" of phosphate, sugar and base called a nucleotide. Nucleotides are the fundamental "units" of the larger molecules of DNA and RNA.

Remember this difference this way. Nucleoside stops at sugar but nucleotide takes a phosphate.

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