Nucleotide pairing

T-A pair, with 2 hydrogen bonds.

Quiz:

After colouring , find out which is each nucleotide:

these adenosine thymidine
or else adenosine thymidine

Spacefilling model: note how close together the bases are.

The base pair is nearly flat, and the pentose rings are perpendicular to it.

C-G pair, with 3 hydrogen bonds.

Quiz:

Colour and identify:

guanosine cytidine
guanosine cytidine

Click to see the two pairs, T-A and C-G, side by side.