Acesulfame potassium is a calorie-free sugar substitute (artificial sweetener), also known as Acesulfame K or...
Acetyl coenzyme A or acetyl-CoA is an important molecule in metabolism, used in many biochemical reactions. Its...
Acetylation (or in IUPAC nomenclature ethanoylation) describes a reaction that introduces an acetyl functional...
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells (the only known exception...
In chemistry, acylation is the process of adding an acyl group to a compound. The compound providing the acyl...
In enzymology, an acylphosphatase is an enzyme that catalyzes the following chemical reaction with...
Adenine (A, Ade) is a nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular...
Adenosine diphosphate, abbreviated ADP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with...
Adenosine-5-triphosphate (ATP) is a multifunctional nucleoside triphosphate.
ATP transports chemical energy...
Attention deficit hyperactivity disorder (ADHD) is a developmental disorder. It is characterized primarily by...
Adoptive cell transfer is the passive transfer of cells, most commonly immune-derived cells, into a new recipient...
Aerenchyma refers to spaces or air channels in the leaves, stems and roots of some plants, which allows exchange...
Aerobic process or environment is one in which is a sufficient amount of molecular oxygen. The amount of oxygen is...
Aflatoxins are naturally occurring mycotoxins that are produced by many species of Aspergillus, a fungus, the most...
Agrobacterium tumefaciens (updated scientific name: Rhizobacterium tumefaciens) is the causal agent of crown gall...
An aldose is a monosaccharide (a simple sugar) that contains only one aldehyde (-CH=O) group per molecule. The...
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This...
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as...
An allele is one of two or more forms of a gene or a genetic locus. Sometimes, different alleles can result...
An allergen is any substance that can cause an allergy.
In technical terms, an allergen is an antigen capable of...
An allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person\'s immune...
Alpha helix is a common motif in the secondary structure of proteins.
It is a right-handed coiled or spiral...
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair.
Amines...
Amino acids are molecules containing an amine group, a carboxylic acid group, and a side-chain that is...
Amyl nitrite is the chemical compound with the formula C5H11ONO. A variety of isomers are known, but they all...
Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva,...
Amyotrophic lateral sclerosis (ALS), also referred to as Lou Gehrig\'s disease in American English and motor...
Anaerobic process or environment is one where atmospheric oxygen is not present.
In such conditions, the...
Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the...
Aneuploidy is an abnormal number of chromosomes, and is a type of chromosome abnormality. An extra or missing...
An aneurysm or aneurism is a localized, blood-filled balloon-like bulge in the wall of a blood vessel.
Aneurysms...
Anosmia is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be...
Anthocyanins (also anthocyans) are water-soluble vacuolar pigments that may appear red, purple, or blue depending...
An antigen is a foreign molecule that, when introduced into the body, triggers the production of an antibody by...
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation reactions can...
The aorta is the largest artery in the body. It is originating from the left ventricle of the heart and...
Arginine (abbreviated as Arg or R) is an amino acid. The L-form is one of the 20 most common natural amino...
Antisense RNA (aRNA) is a single-stranded RNA that is complementary to a messenger RNA (mRNA) strand transcribed...
Aspartame is an artificial, non-saccharide sweetener used as a sugar substitute in some foods and beverages....
Assimilation in biology is the formation of self cellular material from small molecules derived from food...
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively...
In biogeography, a species is defined as native (or autochthonous / indigenous) to a given region or ecosystem if...
An autoclave is a device used to sterilize equipment and supplies by subjecting them to high pressure saturated...
An autopsy—also known as a postmortem examination, necropsy (particularly as to non-human bodies), autopsia...
An autosome is a chromosome that is not an allosome (i.e., not a sex chromosome).
Autosomes appear in pairs whose...
An autotroph is an organism that produces complex organic compounds from simple substances present in...
Auxins are a class of plant hormones (or plant growth substances) with some morphogen-like chara...