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The building blocks of DNA, composed of a phosphate group, deoxyribose sugar, and a nitrogenous base.


A sugar that is derived from ribose - containing five carbons, 10 hydrogens, and 4 oxygens.

Nitrogenous base

Bases used in the construction of nucleotides.


PO4-3, composed of phosphorus and oxygen.


Nitrogenous base paired with thymine.


Nitrogenous based paired with adenine.


Nitrogenous base paired with cytosine.


Nitrogenous base paired with guanine.


Each of these is shaped like a spiral staircase, used in DNA.

Complementary base pairs

The two bases that make up each rung - two combinations: adenine-thymine and cytosine-guanine.

Hydrogen bonds

Bonds that help hold complementary base pairs together.

Double helix

Shape that DNA molecules take the form of.

Sugar-phosphate backbone

Strands that form the double helix shape.

Covalent bonds

The bonds that link the 5-carbon sugars to the phosphates in the backbone.


The component of the DNA molecule that polarizes it, causing it to react positively to water.


Adenine and guanine.


Uracil, thymine, and cytosine.

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