You can see the double helix part of the molecule by tracing the red and orange tetrahedral PO4 groups along the outside. The PO4 groups are linked together by a sugar named Deoxyribose:

This chain of PO4 groups and sugar molecules forms the "double helix" backbone of the DNA molecule.


The two helices are held together by “base pairs” that resemble the steps in a “spiral staircase”.


The two bases in the base pair are each connected to one of the helix backbones and are held together by hydrogen bonds (represented as white dashed lines). Highlight the base pair at the end of the molecule by clicking below.

DNA


To rotate the cell, move the cursor inside the applet frame while holding down the (left) mouse button.

To re-size the display, drag the cursor up while holding down the shift button (to shrink) or drag the cursor down while holding down the shift button (to enlarge).