micro ch 6

NADP+

NAD phosphate

nicotinamide adenine dinucleotide

NAD+

fermentation

provides a solution to the problem of cells that cannot respire, but it results in only the partial oxidation of glucose

transition step

removes CO2, generates reducing power, and joins the resulting acetyl group to a compound called coenzyme A, forming acetyl-CoA

Etner-Doudoroff pathway

some bacteria have this pathway instead of or in addition to glycolysis

cofactor

some enzymes act with the assistance of a non-protein component called this

reactants

starting compounds

potential energy

stored energy

oxidative phosphorylation

synthesis of ATP using the energy of a proton motive force created by harvesting chemical energy

photophosphorylation

synthesis of ATP using the energy of a proton motive force created by harvesting radiant energy

substrate-level phosphorylation

synthesis of ATP using the energy released in an exergonic (energy-releasing) chemical reaction

reducing power

the cell's reserve of H atoms, these are used to reduce metabolic intermediates and thereby drive subsequent steps in cellluar synthesis. can also be used to generate ATP. it is created in many dehydrogenation reactions that occur in catabolic pathway

affinity

the chemical attraction

terminal electron acceptor

the compound at the end of an electron chain. In aerobic respiration, it is oxygen. By accepting electrons from the electron transport chain, the oxygen is reduced to water

feedback inhibition

the end product of a given biosynthetic pathway generally acts as an allosteric inhibitor of the first enzyme of that pathway

free energy

the energy available to do work; the energy that can be released when a chemical bond is broken

adenosine triphosphate

the energy currency of a cell, serving as the ready and immediate donor of free energy

adenosine triphosphate

the energy currency of cells. Hydrolysis of its unstable phosphate bonds can be used to power endergonic (energy-consuming) reactions

activation energy

the energy it takes to initiate a chemical reaction

end product

the final product of a reaction

proton motive force

the form of energy that results form the electrochemical gradient established as protons are expelled from the cell

competitive inhibition

the inhibitor binds to the active site of the enzyme, obstructing access of the substrate to that site

reduced

the molecule that gains electrons becomes this

oxidized

the molecule that loses electrons becomes this

glycolysis

the most common pathway that initiates the breakdown of sugars

metabolism

the sum total of chemical reactions used for biosynthetic and energy-harvesting processes

high-energy phosphate bonds

there is a relatively high amount of free energy released when the bonds between the phosphate groups are hydrolyzed, so they are called this

investment or preparatory phase

this consumes energy because two different steps transfer a high-energy phosphate group to the 6-carbon sugar

tricarboxylic acid cycle (TCA cycle), Krebs cycle, or citric acid cycle

this initiates a series of oxidations that result in the release of two molecules of CO2. For every acetyl-CoA that enters this, the cyclic pathway turns once. It must turn twice to complete the oxidation of one molecule of glucose

pay-off phase

this oxidizes and rearranges the 3-carbon molecules to form pyruvate, generating 1 NADH and 2 ATP

central metabolic pathways

three key metabolic pathways that are used to gradually oxidize glucose, the preferred energy source of many cells, completely to CO2

anaerobic respiration

uses a molecule other than O2 as a terminal electron acceptor

substrate-level phosphorylation

uses the chemical energy released in an exergonic reaction to add Pi to ADP

respiration

uses the reducing power accumulated in glycolysis, the transition step, and the TCA cycle to generate ATP by oxidative phosphorylation

glycolysis

catabolic pathway for phosphoenolpyruvate

glycolysis

catabolic pathway for pyruvate

pentose phosphate cycle

catabolic pathway for ribose 5-phosphate

TCA cycle

catabolic pathway for α-ketoglutarate

terminal electron acceptor

chemical such as O2 that is ultimately reduced as a consequence of fermentation or respiration

flavin adenine dinucleotide

FAD

Buchner

a German chemist, who showed that crushed yeast cells could convert yeast cells could convert sugar to ethanol and CO2

enzyme

a protein that functions as a catalyst, speeding up a biological reaction

hydrogenation

a reduction reaction in which an electron and an accompanying proton are added

active or catalytic site

a relatively small crevice on the surface of the enzyme

allosteric site

a separate site for binding

metabolic pathway

a series of sequential chemical reactions that metabolic processes often occur as

electron carrier

a specific molecule where electrons are temporarily transferred to after they are removed from the energy source

enzyme-substrate complex

a temporary intermediate resulting from the induced fit

pentose phosphate pathway

also breaks down in glucose, but its primary role in metabolism is the production of components used in biosynthesis, including reducing power in the form of NADPH and precursor metabolites

dehydrogenation

an oxidation reaction in which an electron and an accompanying proton are removed is called this

protein (the amino acids cysteine, glycine, and serine)

anabolism or biosynthetic role of 3-phosphoglycerate

lipids (fatty acids)

anabolism or biosynthetic role of Acetyl-CoA

lipids (glycerol component)

anabolism or biosynthetic role of dihydroxyacetone phosphate

protein (the amino acids phenylalanine, tryptophan, and tyrosine)

anabolism or biosynthetic role of erythrose 4-phosphate

peptidoglycan

anabolism or biosynthetic role of fructose 6-phosphate

lipopolysaccharide

anabolism or biosynthetic role of glucose 6-phosphate

protein (the amino acids aspartate, asparagine, isoleucine, lysine, methionine, and threonine

anabolism or biosynthetic role of oxaloacetate

protein (the amino acids phenylalanine, tryptophan, and tyrosine)

anabolism or biosynthetic role of phosphoenolpyruvate

proteins (the amino acids alanine, leucine, and valine)

anabolism or biosynthetic role of pyruvate

nucleic acids and proteins (the amino acid histidine)

anabolism or biosynthetic role of ribose 5-phosphate

protein (the amino acids arginine, glutamate, glutamine, and proline)

anabolism or biosynthetic role of α-ketoglutarate

biosynthesis

another name for anabolism

Embden-Meyerhof-Parnas pathway

another name for glycolysis

precursor metabolites

are metabolic intermediates produced at specific steps in catabolic pathways that can be used in anabolic pathways

allosteric enzymes

can be controlled, have a binding site that is separate from their active site

adenosine diphosphate

can be viewed as an acceptor of free energy

glycolysis

catabolic pathway for 3-phosphoglycerate

transition step

catabolic pathway for Acetyl-CoA

glycolysis

catabolic pathway for dihydroxyacetone phosphate

pentose phosphate cycle

catabolic pathway for erythrose 4-phosphate

glycolysis

catabolic pathway for fructose 6-phosphate

glycolysis

catabolic pathway for glucose 6-phosphate

TCA cycle

catabolic pathway for oxaloacetate

aerobic respiration

electrons are ultimately passed to molecular oxygen , the terminal electron acceptor, producing water

kinetic energy

energy of motion

electron donor

energy source

enzyme

facilitates each step of a metabolic pathway

products

final compounds

proton motive force

form of energy generated as an electron transport chain moves protons across a membrane, creating a chemiosmotic gradient

biofuels

fuels made from a renewable biological source such as plants and organic waste products

photophosphorylation

generate ATP utilizing radiant energy of the sun to drive the formation of a proton motive force

Electron transport chain

group of membrane-embedded electron carriers that pass electrons from one to another, and, in the process, move protons across the membrane to create a proton motive force

oxidative phosphorylation

harvest the energy of proton motive force to add Pi to ADP

photosynthetic organisms

harvest the energy of sunlight, using it to power the synthesis of organic compounds such as glucose

exergonic

if a reaction releases energy, it is said to be this

endergonic

if a reaction requires an input of energy, it is said to be this

energy

is defined as the capacity to do work

precursor metabolites

metabolic intermediates that can either be used to make the subunits of macromolecules, or be oxidized to generate ATP

fermentation

metabolic process that stops short of oxidizing glucose or other organic compounds completely, using an organic intermediate such as pyruvate or a derivative as a terminal electron acceptor

induced fit

mutual interaction of substrate and enzyme

chemoorganotrophs

obtain energy by degrading organic compounds such as glucose, releasing the energy of their chemical bonds

non-competitive inhibition

occurs when the inhibitor and the substrate act at different sites on the enzyme

oxidation-reduction reactions or redox reactions

one or more electrons are transferred from one substance to another

coenzymes

organic cofactors that act as loosely bound carriers of molecules or electrons

respire

organisms that use respiration are said to do this

amphibolic pathways

pathways that are catabolic, but the precursor metabolites and reducing power they generate can also be diverted for use in biosynthesis

respiration

process that involves transfer of electrons stripped from a chemical energy source to an electron transport chain, generating a proton motive force that is then used to synthesize ATP

catabolism

processes that harvest energy released during the breakdown of compounds such as glucose, using it to synthesize ATP

anabolism

processes that utilize energy stored in ATP to synthesize and assemble the subunits (building blocks) of macromolecules that make up the cell; biosynthesis

intermediates

products that are gradually converted into the final product