DNA Structure Activity

Problem 9: Location of GC and AT base pairs in DNA double helix

Return to the "original" view. Perform the following commands:

(1) Select Menu / deoxyribose sugars
(2) Format Menu / Hide Selection (the deoxyribose sugars should all now be hidden)
(3) Select Menu / phosphate groups
(4) Format Menu / Hide Selection (the phosphate groups should also be hidden).

You have just created a view that shows only the bases of the A-T and G-C base pairs . How are the bases oriented in the DNA structure? The planar bases:

A.	stack on top of each other, perpendicular to the helix axis
B.	stack on top of each other, parallel to the helix axis
C.	do not stack on top of each other