In the Watson-Crick Model for the DNA Double Helix (B

question 68

Multiple Choice

In the Watson-Crick model for the DNA double helix (B form) the A-T and G-C base pairs share which property?

• A) The distance between the two glycosidic (base-sugar) bonds is the same in both base pairs, within a few tenths of an angstrom.
• B) The molecular weights of the two base pairs are identical.
• C) The number of hydrogen bonds formed between the two bases of the base pair is the same.
• D) The plane of neither base pair is perpendicular to the axis of the helix.
• E) The proton-binding groups in both base pairs are in their charged or ionized form.

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Definitions:

Recessional Moraine

A ridge of debris deposited at the point of furthest retreat of a glacier or ice sheet.

Continental Ice Sheet

A vast expanse of ice covering a large portion of a continental area, often thousands of kilometers wide and extremely thick.

Teardrop-Shaped Hills

Elongated hills formed by the erosion of underlying soft rock covered by a harder rock cap, often found in arid climates.

Hanging Valley

A glacial valley whose mouth is higher than the bottom of a larger glacially carved valley it joins.