Biology / Unit 6 Bio 1203 short lesson, about 20 seconds
The Nucleotide
Captions available
The idea
A DNA nucleotide is built from a deoxyribose sugar, a phosphate group, and one of four nitrogenous bases: adenine, thymine, guanine, or cytosine.
In practice
Alternating sugar and phosphate groups form each strand's backbone, with one base attached to each sugar.
Where people slip
A nucleotide's base identifies it — the sugar and phosphate are identical across all four DNA nucleotide types.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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