DNA Structure

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Deoxyribonucleic Acid (DNA) Noun

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

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Deoxyribonucleic Acid (DNA)

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A macromolecule that carries the genetic instructions for the development, functioning, growth, and reproduction of all known living organisms.

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

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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 type of macromolecule, such as DNA or RNA, that is essential for life by storing and transmitting genetic information.

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Example: This diagram shows that DNA, a type of nucleic acid, is a double helix structure with a sugar-phosphate backbone and rungs made of base pairs.

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Macromolecule Noun

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[mak-roh-mol-i-kyool]

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Macromolecule

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A very large molecule, such as a protein or nucleic acid, built from smaller chemical units called monomers.

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Example: This diagram shows that macromolecules, like DNA, are large molecules built by joining smaller repeating units (monomers) together, similar to how a chain is made of links.

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Genome Noun

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[jee-nohm]

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Genome

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The complete set of genetic material or instructions present in a cell or organism, encoded in its DNA.

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Example: This diagram shows how an organism's complete set of DNA, its genome, is organized from the DNA molecule into chromosomes, which are located inside the cell's nucleus.

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Chromosome Noun

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[kroh-muh-sohm]

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Chromosome

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A thread-like structure of nucleic acids and protein found in the nucleus, carrying genetic information in the form of genes.

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Example: This image shows that a chromosome is a structure found inside a cell's nucleus and is made of tightly coiled DNA, labeling its key parts.

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Gene Noun

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[jeen]

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Gene

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A specific sequence of nucleotides in DNA that is a unit of heredity, coding for a functional product like a protein.

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Example: This diagram shows that a gene is a specific section of a DNA molecule, which is tightly coiled to form a chromosome inside a cell's nucleus.

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Nucleotide Noun

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[noo-klee-uh-tahyd]

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Nucleotide

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

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Example: A nucleotide, the building block of DNA, is formed when a phosphate molecule, a deoxyribose sugar, and a nitrogenous base are joined together.

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Polymer Noun

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[pol-uh-mer]

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Polymer

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A large molecule composed of many repeating subunits, known as monomers, linked together in a chain, like DNA.

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Example: This image shows that a polymer is a long-chain molecule made by linking many smaller, repeating units called monomers together.

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Deoxyribose Noun

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[dee-ok-see-rahy-bohs]

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Deoxyribose

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The five-carbon sugar molecule that is a component of DNA nucleotides and helps form the sugar-phosphate backbone.

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Example: This image shows Deoxyribose (bottom) and compares it to Ribose (top), highlighting that Deoxyribose is missing an oxygen atom, which is key to its structure in DNA.

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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 molecule that is a component of nucleotides and forms the 'rungs' of the DNA ladder.

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Example: This diagram shows the four types of nitrogenous bases (A, T, C, G) and how they form the 'rungs' of the DNA double helix.