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Cellular and Molecular Biology

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Watson and Crick's First Model of DNA

CELLS-AB7DIG

Watson and Crick's original, unpublished model for the three-dimensional structure of DNA had the nitrogenous bases on the outside of the molecule and phosphate groups on the inside.

Chemically, what makes this model a poor choice?

A

Nitrogenous bases are positively charged and hydrophilic so they are likely to be on the inside of the molecule.

B

Phosphates are positively charged and hydrophilic so they are likely to be on the outside of the molecule.

C

Nitrogenous bases are negatively charged and hydrophilic so they are likely to be on the inside of the molecule.

D

Phosphates are negatively charged and hydrophilic so they are likely to be on the outside of the molecule.