The Structure of DNA

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DNA Noun

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[dee-en-ey]

Back

DNA

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A nucleic acid molecule, structured as a double helix, that contains the genetic instructions for an organism's development and function.

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Example: This diagram shows that DNA is a molecule organized into a chromosome, which is located inside the nucleus of a cell.

Front

Nucleic Acid Noun

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[noo-klee-ik as-id]

Back

Nucleic Acid

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A biological macromolecule, such as DNA or RNA, that is essential for life and built from monomers called nucleotides.

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Example: This diagram shows that a nucleic acid is built from smaller units called nucleotides, each made of a phosphate, a sugar, and a nitrogenous base.

Front

Nucleotide Noun

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[noo-klee-oh-tahyd]

Back

Nucleotide

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The monomer of nucleic acids, composed of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

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Example: This diagram shows that a nucleotide is made of three parts: a phosphate molecule, a deoxyribose sugar, and a nitrogenous base (like adenine).

Front

Deoxyribose Noun

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[dee-ok-see-rahy-bohs]

Back

Deoxyribose

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The five-carbon sugar that is a key component of every DNA nucleotide, forming part of the molecule's backbone.

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Example: This diagram shows the chemical structure of deoxyribose, the five-carbon sugar molecule that forms part of the backbone of a DNA strand.

Front

Phosphate Group Noun

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[fos-feyt groop]

Back

Phosphate Group

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A functional group in a nucleotide that links with the sugar of an adjacent nucleotide to form the DNA backbone.

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Example: This diagram shows that a phosphate group, marked with a 'P', connects sugar molecules together to form the backbone of a DNA strand.

Front

Nitrogenous Base Noun

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[nahy-troj-uh-nuhs beys]

Back

Nitrogenous Base

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A nitrogen-containing molecule that is a component of a nucleotide and forms the basis of the genetic code.

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Example: This diagram shows the four nitrogenous bases (A, T, C, G) and how they pair up to form the rungs of the DNA double helix.

Front

Adenine Noun

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[ad-n-een]

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Adenine

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A purine nitrogenous base found in DNA that specifically pairs with the pyrimidine base thymine through hydrogen bonds.

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Example: This diagram shows the simplified chemical structure of Adenine, one of the four bases in DNA, represented by the letter 'A'.

Front

Guanine Noun

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[gwah-neen]

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Guanine

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A purine nitrogenous base found in DNA that specifically pairs with the pyrimidine base cytosine through hydrogen bonds.

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Example: This image shows the chemical structure of Guanine, a key building block of DNA, labeled with a 'G' for easy identification.

Front

Cytosine Noun

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[sahy-tuh-seen]

Back

Cytosine

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A pyrimidine nitrogenous base found in DNA that specifically pairs with the purine base guanine through hydrogen bonds.

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Example: This diagram shows Cytosine, labeled 'C', as one of the four building blocks of DNA, where it always pairs with Guanine ('G').

Front

Thymine Noun

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[thahy-meen]

Back

Thymine

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A pyrimidine nitrogenous base found in DNA that specifically pairs with the purine base adenine through hydrogen bonds.

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Example: This image shows the simplified chemical structure of Thymine, one of the four building blocks of DNA, clearly labeled with the letter 'T'.