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the sum of all chemical reactions within a living organism


the breakdown of complex organic compounds into simpler ones


the building of complex organic molecules from simpler ones


unique type of RNA, function as catalysts, have active sites that bind to substrates, and are not used up in a chemical reaction


it has gained one or more electrons

redox reaction

oxidation-reduction - pairing of oxidation and reduction


removal of electrons from an atom or molecule, a reaction that often produces energy


biological oxidation resulting in the removal of hydrogen atoms (which is made up of one proton and one electron)


addition of (P) to a chemical compound

substrate-level phosphorylation

ATP is usually generated when a high-energy (P) is directly transferred from a phosphorylated compound (a substrate) to ADP

oxidative phosphorylation

electrons are transferred from organic compounds to one group of electron carriers (usually to NAD+ and FAD)

electron transport chain system

sequence of electron carries used in oxidative phosphorylation


occurs only in photosynthetic cells, which contain light-trapping pigments such as chlorophylls

carbohydrate catabolism

the breakdown of carbohydrate molecules to produce energy

pentose phosphate pathway

or hexose monophosphate shunt, operates simultaneously with glycolysis and provides a means for the breakdown of five-carbon sugars (pentoses) as well as glucose

Entner-Doudoroff pathway

from each molecule of glucose, it produces two molecules of NADPH and one molecule of ATP for use in cellular biosynthetic reactions

cellular respiration

or simply respiration, defined as an ATP-generating process in which molecules are oxidized and the final electron acceptor is (almost always) an inorganic molecule

aerobe respiration

uses oxygen in respiration, the final electron acceptor is O2 (oxygen)

anaerobe respiration

does not use oxygen in respiration, and may even be killed by it; the final electron acceptor is an inorganic molecule other than O2 or, rarely, an organic molecule

Krebs cycle

also called the tricarboxylic acid (TCA) cycle or citric acid cycle, is a series of biochemical reactions in which the large amount of potential chemical energy stored in acetyl CoA is released step by step


the process in a preparatory step that lose one molecule of CO2 and become a two-carbon compound (acetyl group) - attaches to coenzyme A through a high-energy bond, resulting in acetyl coenzyme A. During this reaction, pyruvic acid is also oxidized and NAD+ is reduced to NADH.

electron transport system

consists of a sequence of carrier molecules that are capable of oxidation and reduction


proteins contain flacin, a coenzyme derived from riboflavin (vitamin B2) and are capable of performing alternating oxidations and reductions


proteins with an iron-containing group (heme) capable of existing alternately as a reduced form (Fe2+)


coenzyme Q, symbolized Q, are small nonprotein carriers


mechanism of ATP synthesis using the electron transport chain

Collision Theory

Explains how chemical reactions occur and how certain factors affect the rates of those reactions

Activation Energy

The collision energy required for a chemical reaction


Substances that can speed up a chemical reaction without being permanently altered themselves

Reaction rate

The frequency of collisions containing sufficient energy to bring about a reaction


Biological catalyst which acts on a specific substance and catalyze a specific reaction

Enzyme's substrate

A specific substance on which enzyme acts on

Enzyme-substrate complex

a temporary binding of enzyme and reactants, which enables the collisions to be more effective and lowers the activation energy of the reaction

Turnover Number of enzyme

maximum number of substrate molecules an enzyme molecule converts to product per second


Enzyme Classification- Oxidation-reduction in which oxygen and hydrogen are gained or lost


Enzyme Classification-Transfer of functional groups, such as an amino group, acetyl group, or phosphate group


Enzyme Classification-Hydrolysis (addition of water)


Enzyme Classification-removal of groups of atoms without hydrolysis


Enzyme Classification-Rearrangement of atoms within a molecule


Enzyme Classification-Joining of two molecules (using enerhy usually derived from the breakdown of ATP)


The protein portion of an enzyme


The nom-protein component of an enzyme

Two of the most important coenzyme in cellular metabolism

Nicotinamide adenine dinucleotide (NAD+)
Nicotinamide adenine dinucleotide Phosphate(NADP+)

Coenzyme A

contains derivative of pantothenic acid, another B vitamin

Flavin coenzyme contain derivatives of the B vitamin riboflavin and also are electron carriers

Flavin mononucleotide (FMN)
Flavin adenine dinucleotide (FAD)

Active Site

The surface of the substrate contacts a specific region of the surface of the enzyme molecule


The loss of its characteristic three-dimension structure

When enzyme in saturation

enzyme's active site is always occupied by substrate or product molecule

Competitive inhibitors

Enzyme inhibitors which fill the active site of an enzyme and compete with the normal substrate for the active site

Non-Competitive inhibitors

Enzyme inhibitors which do not compete with the substrate for the active site; instead they interact with another part of the enzyme

Allosteric Inhibition

the inhibitor binds to a site on the enzyme other than the substrate's binding site (allosteric site)

Feedback or end-product inhibition

biochemical control mechanism which stops the cell from wasting chemical resources by making more of a substance than it needs


a unique type RNA which functions as catalysts, have active sites that bind to substrates, and are not used up in a chemical reaction


the removal of electrons from an atom or molecule, a reaction that often produces energy


the gain of one or more electrons to an atom or molecule


redox reaction -- Pairing of oxidation and reduction


oxidation reaction which involves the loss of hydrogen atoms

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