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57 terms

GBBE Ch 5

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metabolism
the sum of all chemical reactions within a living organism
catabolism
the breakdown of complex organic compounds into simpler ones
anabolism
the building of complex organic molecules from simpler ones
ribozyme
unique type of RNA, function as catalysts, have active sites that bind to substrates, and are not used up in a chemical reaction
reduction
it has gained one or more electrons
redox reaction
oxidation-reduction - pairing of oxidation and reduction
oxidation
removal of electrons from an atom or molecule, a reaction that often produces energy
dehydrogenation
biological oxidation resulting in the removal of hydrogen atoms (which is made up of one proton and one electron)
phosphorylation
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
photophos-phorylation
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
decarboxylation
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
flavoproteins
proteins contain flacin, a coenzyme derived from riboflavin (vitamin B2) and are capable of performing alternating oxidations and reductions
cytochromes
proteins with an iron-containing group (heme) capable of existing alternately as a reduced form (Fe2+)
ubiquinones
coenzyme Q, symbolized Q, are small nonprotein carriers
chemiosmosis
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
Catalyst
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
Enzyme
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
Oxidoreductase
Enzyme Classification- Oxidation-reduction in which oxygen and hydrogen are gained or lost
Transferase
Enzyme Classification-Transfer of functional groups, such as an amino group, acetyl group, or phosphate group
Hydrolase
Enzyme Classification-Hydrolysis (addition of water)
Lyase
Enzyme Classification-removal of groups of atoms without hydrolysis
Lsomerase
Enzyme Classification-Rearrangement of atoms within a molecule
ligase
Enzyme Classification-Joining of two molecules (using enerhy usually derived from the breakdown of ATP)
Apoenzyme
The protein portion of an enzyme
Cofactor
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
Denaturation
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
Ribozyme
a unique type RNA which functions as catalysts, have active sites that bind to substrates, and are not used up in a chemical reaction
Oxidation
the removal of electrons from an atom or molecule, a reaction that often produces energy
Reduction
the gain of one or more electrons to an atom or molecule
Oxidation-reduction
redox reaction -- Pairing of oxidation and reduction
Dehydrogenation
oxidation reaction which involves the loss of hydrogen atoms