One who, or that which, precedes an event, and indicates its approach; a forerunner; a harbinger.
A substance, cell, or cellular component from which another substance, cell, or cellular component is formed.
Something that precedes, (for example, Levodopa is a precursor to dopamine in that levodopa is converted to dopamine in the brain).
within a series of chemical and biochemical transformations where one chemical compound leads to another in a synthetic pathway, the precursor is the chemical compound that is necessary for the next chemical compound in the pathway to be synthesized.
A biochemical substance, such as an intermediate compound in a chain of enzymatic reactions, from which a more stable or definitive product is formed.
In metabolism, a chemical substance from which another chemical substance is formed
A substance required for the chemical manufacture of a neurotransmitter.
Literally a "forerunner," such as a substance that precedes another in a biochemical reaction.
compounds that change chemically or physically after being emitted into the air and eventually produce air pollutants. For example, organic compounds are precursors for ozone
A substance containing ephedrine or pseudoephedrine used in the manufacture of methamphetamine.
In photochemistry, a compound antecedent to a pollutant. For example, volatile organic compounds (VOCs) and nitrogen oxides react in sunlight to form ozone or other photochemical oxidants. As such, VOCs and oxides of nitrogen are precursors.
Something that precedes, e.g., a sign or symptom that forewarns of another, such as muscle aching may be the precursor of a tremor.
a person who goes before or announces the coming of another
a chemical substance that is used to synthesize an explosive, poison, drug, etc
a chemical that is not as far along on the chemical pathway chain as the final product
a chemical that when combined with another chemical results in a new product
a chemical which precedes and is the source of another
a commercial chemical that is necessary for the production of a lethal chemical agent
a drug or chemical agent, usually legal in itself, which may (or may not) be possessed for the future manufacture of illegal drugs, usually crystal meth, ecstasy and "club drugs", and new designer drugs
a harbinger, a forerunner
a substance from which another is formed by decay or chemical reaction
a substance from which another substances is formed
a substance that is needed to make another substance in your body
a substance that is used by your body to produce another substance, in the body
A chemical that precedes another in a series of metabolic breakdowns.
Any substance from which another substance is made.
A change in the geological or geophysical conditions that is a forerunner to earthquake generation on a fault. Precursors cannot reliably be recognized as such beforehand.
An intermediate substance in the body's production of another substance.
A precursor is a chemical that is the raw material for a new product. Morphine is a precursor in the production of heroin.
A substance used by the body to form another compound.
A substance that is converted into or used to form an active compound, such as vitamin, hormone or enzyme. Beta carotene is a precursor of vitamin A.
A substance which is converted to another; i.e. Beta Carotene to Vitamin A as it is assimilated by the body.
An intermediate compound (essential ingredient) that is converted to a specific functional substance.
Forerunner. That which precedes or is derived from an available source. See the entire definition of Precursor
a chemical that can be converted by the body into another is a precursor of the latter chemical.
a substance that is used as a building block for another.
A chemical compound which is released into the atmosphere, undergoes a chemical change, and leads to a new (secondary) pollutant. VOCs are precursors to ozone.
something in a stage or a process that precedes a later stage.
a chemical which can be converted to another is a precursor of the latter.
The chemical element that changes due to enzymatic or physical pressure.
Something that precedes.. In biological processes, a substance from which another, usually more active or mature substance is formed. B. In clinical medicine, a sign or symptom that heralds another.
Compounds which lead to other compounds.
A chemical substance required for the manufacture of chemical agent.