DNA Structure and Function

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Nucleic Acid Noun

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[noo-klee-ik as-id]

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Nucleic Acid

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A major class of large biological molecules, including DNA and RNA, that carry genetic information for all life forms.

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Example: A nucleic acid is a large molecule made of repeating units called nucleotides; each nucleotide consists of a phosphate, a sugar, and a nitrogenous base.

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DNA (Deoxyribonucleic Acid) Noun

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[dee-ok-see-rahy-boh-noo-klee-ik as-id]

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DNA (Deoxyribonucleic Acid)

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A self-replicating molecule carrying genetic instructions for the development, functioning, growth, and reproduction of all known living organisms.

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Example: This diagram shows that DNA is a double helix made of a sugar-phosphate backbone and paired bases: Adenine (A) with Thymine (T), and Cytosine (C) with Guanine (G).

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RNA (Ribonucleic Acid) Noun

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[rahy-boh-noo-klee-ik as-id]

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RNA (Ribonucleic Acid)

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A nucleic acid that acts as a messenger, carrying instructions from DNA to control the synthesis of proteins in cells.

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Example: This diagram shows RNA as a single-stranded molecule that is created from a DNA template (transcription) and then used to build proteins (translation).

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Nucleotide Noun

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[noo-klee-oh-tahyd]

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Nucleotide

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The basic building block of nucleic acids, composed of a phosphate group, a five-carbon sugar, and a nitrogenous base.

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Example: This diagram shows the three parts of a nucleotide: a phosphate group, a pentose sugar, and a nitrogenous base, which are the building blocks of DNA.

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Monomer Noun

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[mon-uh-mer]

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Monomer

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A small molecule that can chemically bond with other identical molecules to form a larger molecule called a polymer.

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Example: This diagram shows that a monomer is a single, small molecule, like one bead, that can join with other monomers to form a long chain called a polymer.

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Polymer Noun

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[pol-i-mer]

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Polymer

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A large molecule, or macromolecule, composed of many repeated subunits, known as monomers, that are bonded together.

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Example: A polymer is a large molecule made of repeating units; common examples include natural materials like DNA and wool, and synthetic ones like plastic.

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Nitrogenous Base Noun

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[nahy-troj-uh-nuhs beys]

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Nitrogenous Base

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A nitrogen-containing organic molecule that has the chemical properties of a base and is a fundamental component of nucleotides.

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Example: This diagram shows how the four nitrogenous bases (A, T, C, G) pair together, forming the central 'rungs' of the DNA molecule's structure.

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Purine Noun

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[pyoor-een]

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Purine

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A class of nitrogenous bases characterized by a double-ring structure, which includes adenine and guanine found in nucleic acids.

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Example: This image shows the two types of purines found in DNA, Adenine and Guanine, which are nitrogenous bases with a distinct double-ring chemical structure.

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Pyrimidine Noun

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[pi-rim-i-deen]

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Pyrimidine

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A class of nitrogenous bases characterized by a single-ring structure, including cytosine, thymine, and uracil in nucleic acids.

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Example: This image shows the three pyrimidines (Cytosine, Thymine, Uracil), which are single-ring nitrogenous bases, a key component of DNA and RNA.

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Double Helix Noun

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[duhb-l hee-liks]

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Double Helix

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The characteristic twisted-ladder shape of a DNA molecule, formed by two complementary strands of nucleotides wound around each other.

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Example: This image shows the twisted-ladder shape of a DNA molecule, called a double helix, formed by a sugar-phosphate backbone and paired nitrogenous bases.