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Reagents, such as sulfur (pictured), are the starting materials used in chemical reactions.. In chemistry, a reagent (/ r i ˈ eɪ dʒ ən t / ree-AY-jənt) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. [1]
Biological processes are regulated by many means; examples include the control of gene expression, protein modification or interaction with a protein or substrate molecule. Homeostasis: regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
The energy of activation [1] specifies the amount of free energy the reactants must possess (in addition to their rest energy) in order to initiate their conversion into corresponding products—that is, in order to reach the transition state for the reaction. The energy needed for activation can be quite small, and often it is provided by the ...
For example, curd formation (rennet coagulation) is a reaction that occurs upon adding the enzyme rennin to milk. In this reaction, the substrate is a milk protein (e.g., casein) and the enzyme is rennin. The products are two polypeptides that have been formed by the cleavage of the larger peptide substrate.
Organisation of enzyme structure and lysozyme example. Binding sites in blue, catalytic site in red and peptidoglycan substrate in black. (In biology and biochemistry, the active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction.
Examples of nucleophiles are hydroxide ion, alkoxides, amines and halides. This type of reaction is found mainly in aliphatic hydrocarbons , and rarely in aromatic hydrocarbon . The latter have high electron density and enter nucleophilic aromatic substitution only with very strong electron withdrawing groups .
Metabolism (/ m ə ˈ t æ b ə l ɪ z ə m /, from Greek: μεταβολή metabolē, "change") is the set of life-sustaining chemical reactions in organisms.The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks of proteins, lipids, nucleic acids, and some carbohydrates; and the ...