Biological and Chemical Substance Terms
Naturally occurring and laboratory-made chemicals, nutrients, hormones, and other biomedical substances. Browse definitions and meanings below.
What kinds of substance are covered here?
This vocabulary names the materials biology runs on. Some are made by the body, such as enzymes, hormones and antibodies. Others are taken in, such as minerals and vitamins. Others again are laboratory compounds used to study or to treat disease.
The distinctions that trip people up are functional rather than chemical. An enzyme speeds a reaction without being used up by it. A hormone is a messenger released in one place to act in another. A protein may be either, or neither, because the word describes what a molecule is built from rather than what it does.
Terms in this topic
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Concentration decides everything: the same molecule flavors food, whitens abnormal tissue during an examination, and burns skin as an industrial liquid.
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Acetylcholine is a neurotransmitter that relays signals across synapses to nerve, muscle, and gland cells, supporting memory and muscle contraction.
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An industrial building block for acrylic fiber and hard plastics, not a medicine, with a cyanide-releasing breakdown and a contested cancer record.
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ACTH is a pituitary hormone that signals the adrenal glands to release cortisol, rising during stress and following a natural daily rhythm.
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A single small molecule doing two unrelated jobs: storing information in DNA and shuttling energy as part of ATP.
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Cells hold only a tiny standing amount and recycle it endlessly, so adenosine triphosphate works as a currency rather than as a store of energy.
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Adrenaline is a hormone and neurotransmitter released during stress that rapidly raises heart rate, blood pressure, and alertness.
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A hormone made in the pituitary gland.
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A substance made from shark cartilage that is being studied for its ability to prevent the growth of new blood vessels that tumors need to grow.
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Named after a mouse tumor virus, this switch sits at the center of how a cell decides to grow, survive or store fuel.
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Often read as a nutrition marker, the level falls just as readily with inflammation, liver disease or loss through the kidneys.
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A whole family of compounds in chemistry, though outside the laboratory the word means exactly one of them.
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The reactive group that pickles tissue for the microscope, sterilizes instruments, and forms as the toxic middle step of alcohol breakdown.
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A substance found in certain plants, including aloe vera.
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Alum is an astringent mineral salt used to stop minor bleeding, treat minor skin irritation, and boost vaccine effectiveness.
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Twenty of them, ordered by instructions copied from DNA, are enough to build every protein in the human body.
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A bitter kernel compound sold as a cancer cure under the name laetrile, whose breakdown in the gut releases cyanide.
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Drug design usually starts from a molecule nature already built, alters one part of it, and keeps whatever the alteration improved.
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A hormone made from testosterone in the prostate, testes, and certain other tissues.
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A set of compounds promoted for decades as a cancer treatment, still without approval or an independent trial showing benefit.