Term
| composition of carbohydrates |
|
Definition
| they are C based molecules rich in hydroxyl (-OH) groups |
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|
Term
| empirical formula for many carbohydrates |
|
Definition
|
|
Term
| why carbohydrates can be used for functions as simple as energy storage to as complex as cell-cell recognition |
|
Definition
| because of the vast array of 3d structures that can arise due to the variety of monosaccharides and the multiplicity of linkages that form within carbohydrate polymers |
|
|
Term
| why carbohydrates can form a variety of 3d structures |
|
Definition
| because of the vast array of 3d structures that can arise due to the variety of monosaccharides and the multiplicity of linkages that form within carbohydrate polymers |
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|
Term
|
Definition
| aldehydes or ketones that have 2 or more hydroxyl (-OH) groups |
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|
Term
|
Definition
| carbohydrate that contains a ketone group |
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|
Term
|
Definition
| carbohydrate that contains an aldehyde group |
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|
Term
|
Definition
| carbohydrates that contain 3 C's |
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Term
|
Definition
| have identical molecular formula, but differ in how the atoms are ordered |
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|
Term
|
Definition
| isomers that differ in spatial arrangement |
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Term
|
Definition
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|
Term
|
Definition
| stereoisomers that are not mirror images of each other; they're not enantiomers |
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Term
|
Definition
| diastereoisomers that differ in one of several C atoms |
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|
Term
|
Definition
| diastereoisomers that differ at a new asymmetric C atom formed on ring closure |
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|
Term
| the predominant forms of some monosaccharides in solution |
|
Definition
| cyclic rings instead of open chains |
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|
Term
| the chemical basis for ring formation |
|
Definition
| an aldehyde can react with an alcohol to form a hemiacetal |
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Term
|
Definition
| formed when an aldehyde complexes with an alcohol |
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|
Term
|
Definition
| formed when a ketone complexes with an alcohol |
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|
Term
|
Definition
| OH groups on same side of ring |
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|
Term
|
Definition
| OH groups on different sides of ring |
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|
Term
|
Definition
| the C atom where the molecule can be either the α or β anomer |
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Term
|
Definition
| substituents that are nearly perpendicular to the ring |
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Term
|
Definition
| nearly parallel to the plane of the ring |
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|
Term
| which tend to be more crowded? axial or equatorial substituents? |
|
Definition
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|
Term
|
Definition
| bonds that join monosaccharides to alcohols and amines |
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Term
|
Definition
| bond between the anomeric C atom of a glucose and the O atom of an alcohol |
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|
Term
|
Definition
| bond between the anomeric C atom of a glucose and the N atom of an amine |
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|
Term
| 3 common reactants in the modification of monosaccharides |
|
Definition
-alcohols
-amines
-phosphates |
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|
Term
| the type of bond between adjacent monosaccharides in oligo- and polysaccharides |
|
Definition
|
|
Term
|
Definition
| catalyze the formation of glycosidic bonds |
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Term
|
Definition
| carbohydrate that has a substituent on it attached by a glycosidic bond |
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|
Term
| some common disaccharides |
|
Definition
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|
Term
| some storage forms of glucose |
|
Definition
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|
Term
|
Definition
| polysaccharide in which all the monomer units are the same |
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|
Term
|
Definition
| a polysaccharide that is a storage form of glucose in animals; it's the most common storage form of glucose in animal cells |
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|
Term
| in human tissues, glycogen is most common in... |
|
Definition
|
|
Term
|
Definition
| homopolymer storage form of glucose in plants |
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Term
|
Definition
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|
Term
|
Definition
| unbranched form of starch, consisting of glucose molomers in α-1,4 linkage |
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Term
|
Definition
| branched form of starch having about 1 α-1,6 linkage per 30 α-1,4 linkages |
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|
Term
|
Definition
| enzyme secreted by the salivary glands that readily breaks down amylose, amylopectin, and glycogen |
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|
Term
|
Definition
| structural polysaccharide in plants that is made of glucose monomers joined by a β-1,4 linkage |
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|
Term
| what α and β linkages do for structure of polysaccharides |
|
Definition
| β linkages favor straight chains with H bonding between the strands while α linkages favor bent and helical structures, which are better for storage |
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Term
|
Definition
| protein with a carbohydrate covalently attached to it |
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|
Term
| amount of glycoproteins in the proteome |
|
Definition
| glycoproteins are 50% of the proteome |
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|
Term
| 3 classes of glycoproteins |
|
Definition
-glycoproteins
-proteoglycans
-mucins/mucoproteins |
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|
Term
| composition of glycoproteins |
|
Definition
| protein component is the largest constituent by weight |
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|
Term
| function of glycoproteins |
|
Definition
| many, such as components of cell membranes, where they take part in processes such as cell adhesion and binding of sperm to eggs |
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|
Term
| composition of proteoglycans |
|
Definition
protein component is conjugated to a type of polysac called a glycosyaminoglycan
carbohydrates take up a significant portion of proteoglycans |
|
|
Term
| function of proteoglycans |
|
Definition
-structural components
-lubricants |
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|
Term
|
Definition
| type of polysac that a proteoglycan is conjugated to |
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|
Term
| composition of mucins/mucoproteins |
|
Definition
| predominantly carbohydrate |
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|
Term
| function of mucins/mucoproteins |
|
Definition
|
|
Term
| what determines polysac structure? |
|
Definition
|
|
Term
| amino acids that carbohydrates may be linked to |
|
Definition
-asparagine
-serine
-threonine |
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|
Term
|
Definition
| linking of carbohydrates to asparagine, serine, or threonine |
|
|
Term
| some structural functions of proteoglycans |
|
Definition
-connective tissue
-mediate adhesion of cells to the extracellular matrix
-bind factors that regulate cell proliferation |
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|
Term
| the properties of proteoglycans are determined primarily by... |
|
Definition
| the glycosaminoglycan component |
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|
Term
| composition of many glycosaminoglycans |
|
Definition
made of repeating units of disaccharides containing a derivative of an amino sugar, either glucosamine or galactosamine
at least one of the 2 sugars in the repeating unit has a negatively charged sulfate group |
|
|
Term
|
Definition
| they bind specific carbohydrate structures on neighboring cell surfaces |
|
|
Term
|
Definition
| they facilitate cell-cell contact |
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|
Term
| how lectins facilitate cell-cell contact |
|
Definition
| the lectins on the surface of one cell interact with arrays of carbohydrates displayed on the surface of another cell |
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|
Term
| the 3 stages of generating energy from the oxidation of food |
|
Definition
1: digestion (large molecules being broken down into smaller molecules)
2: numerous small molecules being degraded into a few simple units that play a central role in metabolism; most of these simple units are converted into acetyl CoA
3: producing ATP from the complete oxidation of acetyl CoA; this involves the citric acid cycle and oxidative phosphorylation |
|
|
Term
|
Definition
| large molecules being broken down into smaller molecules |
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|
Term
|
Definition
-tricarboxylic acid (TCA) cycle
-Krebs cycle |
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|
Term
|
Definition
| the extraction of energy from fuels |
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|
Term
| depiction of the stages of catabolism |
|
Definition
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|
Term
| 3 things living organisms need energy for |
|
Definition
1: mechanical work in muscle contraction and cellular movements
2: active transport of molecules and ions
3: synthesis of macromolecules and other biomolecules from simple precursors |
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|
Term
|
Definition
| photosynthetic organisms that obtain energy by trapping sunlight in a chemical form |
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|
Term
|
Definition
| organisms that obtain energy thru the oxidation of C fuels |
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|
Term
| some basic principles that underlie energy flow in all living systems |
|
Definition
1: fuels are degraded and large molecules are constructed step by step in a series of linked rxns called metabolic pathways
2: an energy currency common to all life forms, ATP, links energy releasing pathways with energy requiring pathways
3: the oxidation of C fuels powers the formation of ATP
4: although there are many metabolic pathways, a limited number of types of reactions and particular intermediates are common to many pathways
5: metabolic pathways are highly regulated to allow the efficient use of fuels and to coordinate biosynthetic processes |
|
|
Term
|
Definition
| series of linked rxns in which fuels are degraded and large molecules are constructed |
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|
Term
|
Definition
links energy releasing pathways with energy requiring pathways
this is the energy currency |
|
|
Term
| what powers the formation of ATP? |
|
Definition
|
|
Term
|
Definition
| a linked series of chemical rxns that begins with a particular biomolecule and converts it into some other required biomolecule in a carefully defined fasion |
|
|
Term
|
Definition
| defined metabolic pathways in the cell |
|
|
Term
| 2 broad classes of metabolic pathways |
|
Definition
1: those that convert energy from fuel into biologically useful forms (catabolic)
2: those that require input of energy to proceed (anabolic) |
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|
Term
|
Definition
| breaking down fuels to release cellular energy |
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|
Term
|
Definition
| using energy to synthesize biomolecules |
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|
Term
|
Definition
| can be either anabolic or catabolic, depending on conditions in the cell |
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|
Term
| an important principle of metabolism |
|
Definition
| although biosynthetic and degradative pathways often have rxns in common, the regulated, irreversible reactions of each pathway are almost always distinct from each other |
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|
Term
| how anabolic and catabolic rxns interact |
|
Definition
| energy released from catabolic rxns is used to power anabolic rxns |
|
|
Term
| 2 criteria a metabolic pathway has to meet |
|
Definition
1: the individual rxns must be specific
2: the entire set of rxns that constitute the pathway must be thermodynamically favored |
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|
Term
| the nature of a rxn depends on... |
|
Definition
-the nature of the reactants and products
-the concentrations of reactants and products |
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|
Term
| a thermodynamically unfavorable rxn can be driven by... |
|
Definition
| a thermodynamically favorable rxn |
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|
Term
| ATP can be thought of as... |
|
Definition
| the currency that facilitates the commerce of the cell (metabolism) |
|
|
Term
|
Definition
|
|
Term
|
Definition
| adenine with a triphosphate unit attached |
|
|
Term
|
Definition
| because its triphosphate unit contains 2 phosphoanhydride linkages |
|
|
Term
| phosphoanhydride linkages |
|
Definition
| formed between 2 phosphoryl groups accompanied by the loss of a water molecule |
|
|
Term
| how energy is released from ATP |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| phosphates that can be released from ATP hydrolysis |
|
Definition
|
|
Term
| when ATP is formed from ADP and Pi in chemotrophs |
|
Definition
| when fuel molecules are oxidized |
|
|
Term
| when ATP is formed from ADP and Pi in phototrophs |
|
Definition
|
|
Term
| how an otherwise unfavorable rxn can be made possible |
|
Definition
| by coupling it to ATP hydrolysis |
|
|
Term
| standard free energy of hydrolysis |
|
Definition
| the energy released when the phosphorylated compound transfers the phosphoryl group to water under standard conditions |
|
|
Term
| magnitude of ΔG⁰' vs. phosphoryl-transfer potential |
|
Definition
|
|
Term
| factors that differentiate the stability of the reactants and products |
|
Definition
1: electrostatic repulsion
2: resonance stabilization
3: increase in entropy
4: stabilization due to hydration |
|
|
Term
| how electrostatic repulsion affects stability of reactants and products |
|
Definition
| ATP has 4 negative charges in close proximity to each other; the repulsion between them is reduced when ATP is hydrolyzed |
|
|
Term
| how resonance stabilization affects stability of reactants and products |
|
Definition
| phosphate has greater resonance stabilization when released from ATP |
|
|
Term
| how increase in entropy affects stability of reactants and products |
|
Definition
| products of ATP hydrolysis have 2 molecules instead of 1 |
|
|
Term
| how stabilization due to hydration affects stability of reactants and products |
|
Definition
| water binds to ADP and Pi, making the synthesis of ATP less favorable |
|
|
Term
| why ATP is an efficient carrier of phosphoryl groups |
|
Definition
| because its phosphoryl-transfer potential is intermediate among the biologically important phosphorylated molecules |
|
|
Term
| characteristics of phosphate and its esters that render it useful for biochemical systems |
|
Definition
1: they are thermodynamically unstable, but kinetically stable, thus their energy can be manipulated by enzymes
2: the stability of phosphate esters is due to the negative charges that make them resistant to hydrolysis in the absence of enzymes
3: their kinetic stability makes them ideal regulatory molecules, added to proteins by kinases and removed only by phosphatases |
|
|
Term
| one of the primary roles of catabolism |
|
Definition
|
|
Term
| is ATP an immediate or ling term donor of free energy? |
|
Definition
|
|
Term
| the fundamental mode of energy exchange in biological systems |
|
Definition
|
|
Term
| depiction of the ATP-ADP cycle |
|
Definition
|
|
Term
| some things that require ATP |
|
Definition
-motion
-active transport
-biosynthesis
-signal amplification |
|
|
Term
| some things that turn ADP into ATP |
|
Definition
-oxidation of fuel molecules
-photosynthesis |
|
|
Term
|
Definition
| rxns where one atom loses electrons (oxidation) and another gains electrons (reduction) |
|
|
Term
| reduction of a C atom vs. free energy released by its oxidation |
|
Definition
proportional
the more reduced it tis to begin with, the higher the free energy released by its oxidation |
|
|
Term
| why fats are more efficient fuels than carbohydrates |
|
Definition
| because the C's in fats are more reduced |
|
|
Term
| what happens to the energy of oxidation in ATP synthesis? |
|
Definition
| it is initially trapped as a high-phosphoryl-transfer-potential compound and then used to form ATP |
|
|
Term
| what C oxidation energy is used for in the formation of ATP |
|
Definition
-creating a compound with high phosphoryl-transfer potential
-creating an ion gradient |
|
|
Term
| what is glucose usually metabolized into? |
|
Definition
| CO2 and water; this happens when oxygen delivery is adequate |
|
|
Term
| what happens when ATP needs outpace oxygen delivery? |
|
Definition
| glucose is metabolized to lactate |
|
|
Term
| some speculated reasons for glucose being such a prominent fuel as opposed to other monosaccharides |
|
Definition
1: it is one of several monosacs formed from formaldehyde under prebiotic conditions, so it might have been available for primitive biochem systems
2: glucose is a stable hexose because the hydroxyl groups and hydroxyymethyl group are all equatorial, minimizing steric clashes
3: relative to other monosacs, glucose has a low tendency to glycolysate proteins; this is due to its strong tendency to form rings |
|
|
Term
| why glucose might have been available for primitive biochem systems |
|
Definition
| because it is one of several monosacs formed from formaldehyde under prebiotic conditions |
|
|
Term
| why glucose is a stable hexose |
|
Definition
| because the hydroxyl groups and hydroxyymethyl group are all equatorial, minimizing steric clashes |
|
|
Term
| why glucose has a low tendency to glycolysate proteins |
|
Definition
| because of its strong tendency to form rings |
|
|
Term
| where glycolysis occurs in eukaryotic cells |
|
Definition
|
|
Term
| what glucose is converted to in gylycolysis |
|
Definition
| 2 molecules of pyruvate with the concomitant generation of 2 molecules of ATP |
|
|
Term
| stage 1 of glycolysis begins with... |
|
Definition
| the conversion of glucose into fructose 1,6-biphosphate |
|
|
Term
| the 3 steps of converting glucose into fructose 1,6-biphosphate |
|
Definition
1: phosphorylation
2: isomerization
3: 2nd phosphorylation |
|
|
Term
| the strategy of the initial steps of glycolysis |
|
Definition
| to trap the glucose in the cell and form a compound that can be readily cleaved into phosphorylated 3-C units |
|
|
Term
| stage 1 of glycolysis is completed by... |
|
Definition
| the cleavage of fructose 1,6-biphosphate into 2 phosphorylated, 3-C fragments |
|
|
Term
| what happens in stage 1 of glycolysis? |
|
Definition
| glucose is trapped, destabilized, and cleaved into 2 interconvertible 3-C molecules, generated by the cleavage of 6-C fructose |
|
|
Term
| what happens in stage 2 of glycolysis? |
|
Definition
| the 2 3-C units are oxidized to pyruvate, generating ATP |
|
|
Term
| depiction of the stages of glycolysis |
|
Definition
|
|
Term
| the one principal fate glucose has inside the cell |
|
Definition
| it is phosphorylated by ATP to form glucose 6-phosphate |
|
|
Term
|
Definition
catalyzes the transfer of the phosphoryl group from ATP to the hydroxyl group on C6 of glucose
traps glucose in the cell and begins glycolysis |
|
|
Term
| depiction of the function of hexokinase |
|
Definition
|
|
Term
|
Definition
| enzyme that catalyzes the transfer of a phosphoryl group from ATP to an acceptor |
|
|
Term
| something kinases require for activity |
|
Definition
| divalent metal cations, such as Mg2+ and Mn2+
this forms a complex with ATP |
|
|
Term
| fructose 1,6-biphosphate is generated from... |
|
Definition
|
|
Term
|
Definition
catalyzes the isomerization of glucose 6-phosphate to to fructose 6-phosphate
this is the conversion of an aldose to a ketose |
|
|
Term
| depiction of the function of phosphoglucose isomerase |
|
Definition
|
|
Term
| what happens to fructose 6-phosphate during glycolysis? |
|
Definition
| gets phosphorylated by ATP to fructose 1,6-biphosphate |
|
|
Term
| phosphofructokinase (PFK) |
|
Definition
| catalyzes the phosphorylation of fructose 6-phosphate to fructose 1,6-biphosphate |
|
|
Term
| depiction of the function of phosphofructokinase (PFK) |
|
Definition
|
|
Term
| an allosteric enzyme that is the key regulatory enzyme for glycolysis |
|
Definition
|
|
Term
| what the oxidation of aldehyde does in glycolysis |
|
Definition
| powers the formation of a compound having high phosphoryl-transfer potential |
|
|
Term
| glyceraldehyde 3-phosphate dehydrogenase |
|
Definition
| catalyzes the conversion of glyceraldehyde 3-phosphate into 1,3-biphosphoglycerate |
|
|
Term
|
Definition
| enzyme that catalyzes redox rxns, often transferring a hydride ion from a donor molecule to NAD+ or transferring a hydride ion from NADH to an acceptor molecule |
|
|
Term
| depiction of the function of glyceraldehyde 3-phosphate dehydrogenase |
|
Definition
|
|
Term
| the energy of C oxidation is transferred as... |
|
Definition
| high phosphoryl-transfer potential |
|
|
Term
| detailed depiction of the conversion of glyceraldehyde 3-phosphate into 1,3-biphosphoglycerate |
|
Definition
|
|
Term
| what couples the aldehyde oxidation to drive the formation of the acyl phosphate? |
|
Definition
| an enzyme that forms a thioester intermediate, replacing the H on the aldehyde group and later being replaced by an orthophosphate group |
|
|
Term
| depiction of the function of the thioester intermediate that couples the aldehyde oxidation to drive the formation of the acyl phosphate |
|
Definition
[image]
reduces the activation energy; intermediate more stable than reactants, but more stable than products, making it spontaneous |
|
|
Term
| in glycolysis, ATP is formed by... |
|
Definition
| phosphoryl transfer from 1,3-biphosphoglycerate |
|
|
Term
|
Definition
| catalyzes the transfer of the phosphoryl group from the acyl phosphate of 1,3-biphosphoglycerate to ADP, which yields ATP and 3-phosphoglycerate |
|
|
Term
| depiction of the function of phodsphoglycerate kinase |
|
Definition
|
|
Term
| how additional ATP is generated at the end of glycolysis |
|
Definition
| by converting 3-phosphoglycerate into pyruvate, which forms a 2nd molecule of ASTP |
|
|
Term
| depiction of 3-phosphoglycerate being converted into pyruvate to form ATP |
|
Definition
|
|
Term
|
Definition
| shifts the position of the phosphoryl group to convert 3-phosphoglycerate into 2-phosphoglycerate |
|
|
Term
| depiction of the function of phosphoglycerate mutase |
|
Definition
|
|
Term
|
Definition
| catalyzes the intramolecular shift of a chemical group |
|
|
Term
|
Definition
| catalyzes the formation of the enol phosphate phosphoenolpyruvate (PEP), which is unstable and has a high phosphoryl transfer potential |
|
|
Term
| depiction of the function of enolase |
|
Definition
|
|
Term
|
Definition
| catalyzes the irreversible transfer of a phosphoryl group from phosphoenolpyruvate (PEP) to ADP |
|
|
Term
| depiction of the function of pyruvate kinase |
|
Definition
|
|
Term
| the net rxn of the transformation of glucose into pyruvate |
|
Definition
| glucose + 2 Pi + 2 ADP + 2 NAD+ ---> 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O |
|
|
Term
| why a glycolysis pathway that ends with pyruvate will not proceed |
|
Definition
| because this would result in oxidation-reduction imbalance |
|
|
Term
| the final process in glycolysis |
|
Definition
| the regeneration of NAD+ thru the metabolism of pyruvate |
|
|
Term
| 3 rxns of pyruvate that can occur in living things |
|
Definition
| -conversion into ethanol
-conversion into lactate
-conversion into CO2 and water |
|
|
Term
| types of fermentation that can occur with pyruvate in the absence of O |
|
Definition
-conversion into ethanol
-conversion into lactate |
|
|
Term
|
Definition
| ATP-generating process in which organic compounds act as both donors and acceptors of electrons |
|
|
Term
| what happens to pyruvate in the presence of O? |
|
Definition
| gets metabolized to CO2 and water thru the citric acid cycle and the electron transport chain |
|
|
Term
| depiction of the possible fates of pyruvate |
|
Definition
|
|
Term
|
Definition
| catalyzes the decarboxylation of pyruvate |
|
|
Term
| depiction of the function of pyruvate decarboxylase |
|
Definition
|
|
Term
|
Definition
| catalyzes the reduction of acetaldehyde to ethanol by NADH |
|
|
Term
| depiction of the function of alcohol dehydrogenase |
|
Definition
|
|
Term
|
Definition
| converting glucose into alcohol |
|
|
Term
| the net result of the anaerobic conversion of glucose into ethanol |
|
Definition
| glucose + 2Pi + 2 ADP + 2 H+ --> 2 ethanol 2 CO2 + 2 ATP + 2 H2O |
|
|
Term
| how redox balance is maintained in alcohol fermentation |
|
Definition
| production and later consumption of NADH; no net proiduction of NADH or NAD+ |
|
|
Term
| depiction of how redox balance is maintained in alcoholic fermentation |
|
Definition
|
|
Term
|
Definition
| converting glucose into lactate |
|
|
Term
|
Definition
| catalyzes the conversion of pyruvate to lactate |
|
|
Term
| depiction of the function of lactate dehydrogenase |
|
Definition
|
|
Term
| overall rxn in the conversion of glucose to lactate |
|
Definition
| glucose + 2Pi + 2 ADP --> 2 lactate + 2 ATP + 2 H2O |
|
|
Term
| how redox balance is maintained in lactate fermentation |
|
Definition
| production and later consumption of NADH; no net proiduction of NADH or NAD+ |
|
|
Term
| this sustains glycolysis under anaerobic conditions |
|
Definition
| the regeneration of NAD+ from NADH; using the NAD+ that's produced and using the NADH that's produced |
|
|
Term
| depiction of how redox balance is maintained in lactic acid fermentation |
|
Definition
|
|
Term
| type of cell in animals that can function anaerobically for a short time |
|
Definition
| fast twitch, or type IIb, muscle |
|
|
Term
| which type of glycolysis releases more energy? aerobic or anaerobic? |
|
Definition
|
|
Term
| how energy is extracted aerobically |
|
Definition
| by means of the citric acid cycle and the electron transport chain, which combust, or oxidize, glucose into H2O and CO2 |
|
|
Term
| the entry point to the oxidative pathway in aerobic glycolysis |
|
Definition
| acetyl coenzyme A (acetyl CoA) |
|
|
Term
|
Definition
| formed from pyruvate inside mitochondria |
|
|
Term
| the process by which mitochondria form acetyl CoA |
|
Definition
| pyruvate + NAD+ + CoA --> acetyl CoA + CO2 + NADH |
|
|
Term
| how the NAD+ needed for aerobic glycolysis is regenerated |
|
Definition
| regenerated by the electron transport chain in mitochondria |
|
|
Term
| some recurring motifs in biochemistry |
|
Definition
1: the use of activated carriers
2: the existence of a recurring set of activated characters in all organisms |
|
|
Term
| why ATP is an activated carrier of phosphoryl groups |
|
Definition
| because phosphoryl transfer from ATP is energetically favorable |
|
|
Term
| a recurring motif in biochem |
|
Definition
| the use of activated carriers |
|
|
Term
|
Definition
| small molecule carrying activate functional groups that can be donated to another molecule |
|
|
Term
| examples of activated carriers |
|
Definition
-ATP carries activated phosphoryl groups
-coenzyme A carries activated acyl groups
-activated carriers of electrons for fuel oxidation
-activated carriers of electrons for the synthesis of biomolecules
-an activated carrier of 2-Carbon fragments |
|
|
Term
| many activated carriers function as... |
|
Definition
|
|
Term
|
Definition
| small organic molecules that serve as cofactors for enzymes |
|
|
Term
| the ultimate electron acceptor in the oxidation of fuel molecules |
|
Definition
|
|
Term
| the flow of electrons from fuel molecules to O2 |
|
Definition
| fuel molecules --> pyridine nucleotides or flavins --> O2 |
|
|
Term
| an example of a pyridine nucleotide |
|
Definition
|
|
Term
|
Definition
| a pyridine nucleotide that is a major electron carrier in the oxidation of fuel molecules |
|
|
Term
|
Definition
|
|
Term
| depiction of NAD+ reduction |
|
Definition
|
|
Term
| depiction of redox rxn involving NAD+ |
|
Definition
|
|
Term
| major electron carriers in the oxidation of fuel molecules |
|
Definition
| -NAD+
-FAD
these are both oxidized forms |
|
|
Term
|
Definition
|
|
Term
| depiction of redox rxn involving FAD |
|
Definition
|
|
Term
| oxidized and reduced forms of FAD/FADH2 |
|
Definition
|
|
Term
|
Definition
| synthesizing something from precursors that are more oxidized than the products |
|
|
Term
| most biosynthesis is this type of biosynthesis |
|
Definition
|
|
Term
| the electron donor in most biosynthesis |
|
Definition
|
|
Term
|
Definition
|
|
Term
| key difference between NADH and NADPH |
|
Definition
| NADPH contains one more phosphate group |
|
|
Term
| key difference between the uses of NADH and NADPH |
|
Definition
| NADPH used almost exclusively for reductive biosynthesis while NADH is used primarily for the generation of ATP |
|
|
Term
|
Definition
| almost exclusively for reductive biosynthesis while NADH is used primarily for the generation of ATP |
|
|
Term
|
Definition
| primarily the generation of ATP |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| why acetyl CoA has high acetyl group transfer potential |
|
Definition
| because transfer of the acetyl group is exergonic (i.e., thermodynamically favorable) |
|
|
Term
| why the kinetic stability of NADH, NADPH, FADH2, ATP, and acetyl CoA in the absence of specific catalysts is essential foor their biological function |
|
Definition
| because it allows enzymes to control the flow of free energy and reducing power |
|
|
Term
| one of the unifying motifs in biochem |
|
Definition
| the existence of a recurring set of activated characters in all organisms |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| many activated carriers are derived from... |
|
Definition
|
|
Term
|
Definition
| organic molecules needed in small amounts in the diets of many higher animals |
|
|
Term
| the dual role of the glycolytic pathway |
|
Definition
-degrades glucose to generate ATP
-provides building blocks for biosynthetic rxns |
|
|
Term
| potential sites of control in metabolic pathways |
|
Definition
| enzymes catalyzing irreversible rxns |
|
|
Term
| the control sites (i.e., enzymes tat catalyze irreversible rxns) in glycolysis |
|
Definition
-hexokinase
-phosphofructokinase
-pyruvate kinase |
|
|
Term
| the type of enzymes that regulate glycolysis |
|
Definition
|
|
Term
| what glycolysis in muscle does |
|
Definition
| primarily provides power for muscle contraction |
|
|
Term
| the primary control of muscle glycolysis |
|
Definition
| energy charge of the cell- ratio of ATP to AMP |
|
|
Term
| energy charge of the cell |
|
Definition
|
|
Term
| glycolysis in muscle is regulated by... |
|
Definition
| feedback inhibition to meet the need for ATP |
|
|
Term
| the most important control site in the mammalian glycolytic pathway |
|
Definition
|
|
Term
| how phosphofructokinase is inhibited in muscle |
|
Definition
ATP binds with phosphofructokinase at a distinct site to lower its affinity for fructose 6-phosphate
can also be inhibited by declining pH |
|
|
Term
| how phosphofructokinase is stimulated in muscle |
|
Definition
| AMP binds with phosphofructokinase at the same site to increase its affinity for fructose 6-phosphate |
|
|
Term
| how muscle cells are protected from excess acidity |
|
Definition
| lactic acid lowers the pH, augmenting the inhibitory effect of ATP on phosphofructokinase |
|
|
Term
| why AMP, not ADP, stimulates phosphofructokinase activity |
|
Definition
| because while ATP is being used, aldenylate kinase can convert ADP into ATP |
|
|
Term
|
Definition
|
|
Term
| the rxn aldenylate kinase is involved in |
|
Definition
|
|
Term
| the primary regulatory enzyme in glycolysis |
|
Definition
|
|
Term
| how hexokinase is regulated in muscle |
|
Definition
| it is inhibited by accumulation of glucose 6-phosphate |
|
|
Term
| how inhibition of phosphofructokinase leads to inhibition of hexokinase |
|
Definition
| inhibition of PFK leads to accumulation of fructose 6-phosphate, leading to accumulation of glucose 6-phosphate, leading to inhibition of hexokinase |
|
|
Term
| why hexokinase is not the committed step in glycolysis |
|
Definition
| because glucose 6-phosphate can also be converted into glycogen |
|
|
Term
| why PFK is the committed step in glycolysis |
|
Definition
| because it's the first step unique to glycolysis |
|
|
Term
| why the committed step is the most important controlled element in a biochemical pathway |
|
Definition
| because it regulates flux down the pathway |
|
|
Term
| how pyruvate kinase is inhibited in muscle |
|
Definition
| ATP binds to pyruvate kinase to decrease its affinity for phosphoenolpyruvate |
|
|
Term
| how pyruvate kinase is stimulated in muscle |
|
Definition
| fructose 1,6-bisphosphate activates the kinase to enable it to keep pace with the oncoming flux of intermediates |
|
|
Term
| depiction of glycolysis being inhibited in muscle (at rest) |
|
Definition
|
|
Term
| depiction of glycolysis being stimulated in muscle (during exercise) |
|
Definition
|
|
Term
| the regulation of glycolysis in the liver corresponds to... |
|
Definition
| the biochemical versatility of the liver |
|
|
Term
| how the liver regulates blood glucose |
|
Definition
-stores it as glycogen when high
-releases glucose when low |
|
|
Term
| some things the liver does with glucose |
|
Definition
-stores it as glycogen when high
-releases glucose when low
-uses glucose to generate reducing power for biosynthesis
-synthesize a host of building blocks for other biomolecules |
|
|
Term
| how PFK in the liver is inhibited |
|
Definition
| citrate, since citrate accumulation indicates that there's already enough biosynthetic precursors |
|
|
Term
| the key means by which PFK in the liver responds to changes in blood glucose |
|
Definition
| thru the signal molecule fructose 2,6-bisphosphate (F-2,6-BP) |
|
|
Term
| how PFK in the liver is stimulated |
|
Definition
| fructose 2,6-bisphosphate stimulates PFK by increasing its affinity for fructose 6-phosphate |
|
|
Term
| the enzyme primarily responsible for phosphorylating glucose in the liver |
|
Definition
| glucokinase (hexokinase IV) |
|
|
Term
| glucokinase (hexokinase IV) |
|
Definition
| isozyme of hexokinase; this is what's primarily responsible for phosphorylating glucose in the liver |
|
|
Term
|
Definition
| enzymes encoded by different genes with different amino acid sequences, but catalyze the same rxns |
|
|
Term
| how isozymes/isoenzymes differ |
|
Definition
| usually by kinetic or regulatory properties |
|
|
Term
| some differences between hexokinase and glucokinase |
|
Definition
| glucokinase has a higher KM value and is not inhibited by its product, glucose 6-phosphate |
|
|
Term
|
Definition
| to provide glucose 6-phosphate for the synthesis of glycogen and for the formation of fatty acids |
|
|
Term
|
Definition
| the need to remove glucose from thew blood for storage as glycogen or conversion into fat |
|
|
Term
| some important forms of pyruvate kinase |
|
Definition
|
|
Term
| the form of pyruvate kinase that predominates in the liver |
|
Definition
|
|
Term
| the form of pyruvate kinase that predominates in the muscle and brain |
|
Definition
|
|
Term
| which form of pyruvate kinase is inhibited by alanine? |
|
Definition
| the L form (liver enzyme) |
|
|
Term
| reversible phosphorylation regulates the catalytic properties of which form of pyruvate kinase? |
|
Definition
| the L form (liver enzyme) |
|
|
Term
| the importance of reversible phosphorylation regulating the catalytic properties of the L form of pyruvate kinase (liver enzyme) |
|
Definition
| prevents the liver from consuming glucose when it is more urgently needed by brain and muscle |
|
|
Term
| the function of the GLUT1 to GLUT5 proteins |
|
Definition
| enable glucose to enter and leave animal cells |
|
|
Term
| where the GLUT1 protein is found |
|
Definition
| nearly all mammalian cells |
|
|
Term
| where the GLUT3 protein is found |
|
Definition
| nearly all mammalian cells |
|
|
Term
| the GLUT proteins that essentially continuously transport glucose into cells at a constant rate (function in basal glucose uptake) |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| where the GLUT2 protein is found |
|
Definition
| liver and pancreatic β cells |
|
|
Term
| when glucose enters through the GLUT2 protein at a significant rate |
|
Definition
| when there is much glucose in the blood |
|
|
Term
|
Definition
in pancreas: helps regulate insulin
in liver: removes excess glucose from the blood |
|
|
Term
| where the GLUT4 protein is found |
|
Definition
|
|
Term
| how the number of GLUT4 proteins increases |
|
Definition
-increased insulin, which signals the presence of glucose
-endurance exercise |
|
|
Term
| where the GLUT5 protein is found |
|
Definition
|
|
Term
|
Definition
| primarily as fructose transporter |
|
|
Term
|
Definition
| the synthesis of glucose from noncarboydrate precursors |
|
|
Term
| why it's important to maintain glucose levels |
|
Definition
| because red blood cells need it and the brain uses it as its only fuel source |
|
|
Term
| the part of the body that needs most of the glucose |
|
Definition
|
|
Term
| when gng is especially important |
|
Definition
| during fasting or starvation |
|
|
Term
|
Definition
| mostly liver with small amount occurring in kidney |
|
|
Term
|
Definition
| helps maintain blood glucose so tissues that need it can access it |
|
|
Term
| the gng pathway converts ______ into ______ |
|
Definition
|
|
Term
| the major noncarbohydrate precursors that get involved in gng |
|
Definition
-lactate
-amino acids
-glycerol |
|
|
Term
| how glycerol may enter the gng pathway |
|
Definition
| by conversion of glycerol to dihydroxyacetone phosphate |
|
|
Term
| depiction of the conversion of glycerol to dihydroxyacetone phosphate |
|
Definition
|
|
Term
| is gng a complete reversal of glycolysis? |
|
Definition
|
|
Term
| why is gng not a complete reversal of glycolysis? |
|
Definition
| because the free energy of glycolysis is -90 kJ/mol, making it irreversible and necessary for gng to bypass the irreversible steps |
|
|
Term
|
Definition
|
|
Term
| the conversion of pyruvate into phosphoenolpyruvate begins with... |
|
Definition
| the formation of oxaloacetate |
|
|
Term
|
Definition
| carboxylation of pyruvate to form oxaloacetate |
|
|
Term
|
Definition
| enyme that catalyzes the carboxylation of pyruvate to form oxaloacetate |
|
|
Term
| where the carboxylation of pyruvate to form oxaloacetate occurs |
|
Definition
|
|
Term
| depiction of the carboxylation of pyruvate to form oxaloacetate |
|
Definition
|
|
Term
| importance of biotin to pyruvate carboxylase |
|
Definition
| biotin is a covalently attached prosthetic group that serves as the carrier of activated CO2 |
|
|
Term
| the 3 stages of pyruvate carboxylation |
|
Definition
|
|
Term
| how oxaloacetate is processed in the mitochondria |
|
Definition
in matrix: pyruvate --> oxaloacetate --> malate
in cytoplasm: malate --> oxaloacetate |
|
|
Term
| depiction of how oxaloacetate is processed in the mitochondria |
|
Definition
|
|
Term
| phosphoenolpyruvate carboxykinase (PEPCK) |
|
Definition
| catalyzes the decarboxylation and phosphorylation of of oxaloiacetate |
|
|
Term
| depiction of the function of phosphoenolpyruvate carboxykinase (PEPCK) |
|
Definition
|
|
Term
| the sum of the rxns catalyzed by pyruvate carboxylase and phosphoenolpyruvate carboxylase |
|
Definition
| pyruvate + ATP + GTP + H2O --> phosphoenolpyruvate + ADP + GDP + Pi + 2 H+ |
|
|
Term
| importance of decarboxylation |
|
Definition
| often drives rxns that are otherwise highly endergonic |
|
|
Term
| fructose 1,6-bisphosphotase |
|
Definition
| catalyzes conversion of fructose 1,6-bisphosphate to fructose 6-phosphate |
|
|
Term
| depiction of the function of fructose 1,6-bisphosphotase |
|
Definition
|
|
Term
| where gng ends in most tissues |
|
Definition
| conversion of fructose 6-phosphate into glucose 6-phosphate, which is often stored as glycogen |
|
|
Term
| where the final step in the generation of free glucose occurs |
|
Definition
|
|
Term
| metabolic duty of the liver |
|
Definition
| to maintain adequate levels of glucose in the blood for use by other organs |
|
|
Term
| how glucose 6-phosphate gets converted to free glucose |
|
Definition
| transported into lumen of endoplasmic reticulum, where it is hydrolyzed to glucose by glucose 6-phosphatase, which is bound to the ER membrane.
glucose and Pi are then shuttled out into the cytoplasm by transporters |
|
|
Term
| depiction of generation of glucose from glucose 6-phosphate |
|
Definition
|
|
Term
| the NTP difference between glycolysis and gng |
|
Definition
| glycolysis yields 2 ATP while gng requires 4 ATP and 2 GTP (6 NTP) |
|
|
Term
| when glycolysis predominates |
|
Definition
|
|
Term
|
Definition
|
|
Term
| what determines whether glycolysis or gng will be more active? |
|
Definition
|
|
Term
| the key regulation site in the gng pathway |
|
Definition
| the interconversion of fructose 6-phosphate and fructose 1,6-bisphosphate |
|
|
Term
|
Definition
| seems to be ratio of ATP/AMP |
|
|
Term
| something indicated by high AMP concentration |
|
Definition
| energy is needed, thus stimulating glycolysis and inhibiting gng |
|
|
Term
| something indicated by high ATP concentration |
|
Definition
| the energy charge is high and biosynthetic intermediates are abundant, thus inhibiting glycolysis |
|
|
Term
| something indicated by high citrate concentration |
|
Definition
| reports the status of the citric acid cycle; high citrate indicates energy rich situation and precursors for biosynthesis, inhibiting glycolysis and stimulating gng |
|
|
Term
| where the interconversion of phosphoenolpyruvate and pyruvate occurs |
|
Definition
|
|
Term
| something indicated by high alanine concentration |
|
Definition
| energy charge is hidh and building blocks are abundant, inhibiting pyruvate kinase in glycolysis |
|
|
Term
| depiction of the reciprocal regulation of glycolysis and gng in the liver |
|
Definition
|
|
Term
| phosphofructokinase 2 (PFK2) |
|
Definition
| catalyzes the conversion of fructose 6-phosphate to fructose 2,6-bisphosphate |
|
|
Term
| fructose bisphosphatase 2 (FBPase2) |
|
Definition
| catalyzes conversion of fructose 2,6-bisphosphate to frucose 6-phosphate |
|
|
Term
| something striking about PFK2 and FBPase2 |
|
Definition
| they're both in a single 55-kDa polypeptide chain; it's a bifunctional enzyme |
|
|
Term
| composition of the bifunctional PFK2/FBPase2 enzyme |
|
Definition
| N-terminal regulatory domain followed by a kinase domain and a phosphatase domain |
|
|
Term
| how it is determined whether a bifunctional PFK2/FBPase2 enzyme functions as PFK2 or FBPase2 |
|
Definition
| the activities of PFK2 and FBPase2 are reciprocally controlled by the phosphorylation of a single serine residue |
|
|
Term
| when the bifunctional PFK2/FBPase2 enzyme functions as FBPase2 |
|
Definition
when blood glucose is low
gng predominates |
|
|
Term
| how low blood glucose causes the bifunctional PFK2/FBPase2 enzyme to act as FBPase2 |
|
Definition
| when glucose in scarce, blood glucagon rises and triggers a cyclic AMP signal cascade, leading to the phospkorylation of this enzyme by protein kinase A; this activates FBPase2 and inhibits PFK2 |
|
|
Term
| when the bifunctional PFK2/FBPase2 enzyme functions as PFK2 |
|
Definition
when blood glucose is high
glycolysis predominates |
|
|
Term
| how high blood glucose causes the bifunctional PFK2/FBPase2 enzyme to act as PFK2 |
|
Definition
| glucagon falls and insulin rises, causing the phosphoryl group to be removed; this activates PFK2 and inhibits FBPase2 |
|
|
Term
|
Definition
|
|
Term
| depiction of the bifunctional PFK2/FBPase2 enzyme |
|
Definition
|
|
Term
| depiction of the control of the synthesis and degradation of fructose 2,6-bisphosphate |
|
Definition
|
|
Term
| what lets contracting skeletal muscle generate ATP in the absence of oxygen? |
|
Definition
| the formation and release of lactate |
|
|
Term
| 2 possible fates of lactate |
|
Definition
1: diffuses into cardiac and slow-twitch (type 1) muscle to be reverted to pyruvate to be metabolized thru the citric acid cycle and oxidative phosphorylation to generate ATP
2: excess lactate enters the liver to be converted into pyruvate, then to glucose by the gng pathway |
|
|
Term
| what the liver does for active muscles |
|
Definition
| restores the levels of glucose needed for active muscle cells, which derive ATP from the conversion of glucose into lactate |
|
|
Term
| depiction of a substrate cycle |
|
Definition
|
|
Term
| depiction of the Cori cycle |
|
Definition
|
|
Term
|
Definition
|
|
Term
| the one way link between glycolysis and cellular respiration |
|
Definition
|
|
Term
| what happens to pyruvate in anaerobic conditions? |
|
Definition
| converted to lactic acid or ethanol |
|
|
Term
| what happens to pyruvate in aerobic conditions |
|
Definition
| converted into acetyl coenzyme A (acetyl CoA), which enters the citric acid cycle |
|
|
Term
| what happens to pyruvate when a cell's oxygen supply is insufficient? |
|
Definition
| gets converted to lactate |
|
|
Term
| simplified overview of the citric acid cycle |
|
Definition
|
|
Term
| pyruvate dehydrogenase complex |
|
Definition
| oxidatively decarboxylates pyruvate to form acetyl CoA |
|
|
Term
| the chemical rxn of the pyruvate dehydrogenase complex |
|
Definition
| pyruvate + CoA + NAD+ --> acetyl CoA + CO2 NADH + H+ |
|
|
Term
| where oxidative decarboxylation of pyruvate occurs |
|
Definition
|
|
Term
| where citric acid cycle occurs |
|
Definition
|
|
Term
| the rxn E1 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| oxidative decarboxylation of pyruvate |
|
|
Term
| the rxn E2 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| transfer of acetyl group to CoA |
|
|
Term
| the rxn E3 in the pyruvate dehydrogenase complex catalyzes |
|
Definition
| regeneration of the oxidized form of lipoamide |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| the link between glycolysis and the citric acid cycle |
|
Definition
| the irreversible conversion of pyruvate into acetyl CoA |
|
|
Term
| depiction of the link between glycolysis and the citric acid cycle |
|
Definition
|
|
Term
|
Definition
| function as enzymes; not permanently altered by participation in rxn |
|
|
Term
|
Definition
| they function as substrates |
|
|
Term
| the 3 steps of the conversion of pyruvate into acetyl CoA |
|
Definition
1: decarboxylation
2: oxidation
3: the transfer of the resultant acetyl group to CoA |
|
|
Term
| depiction of the conversion of pyruvate into acetyl CoA |
|
Definition
|
|
Term
|
Definition
| proteins tightly associated with FAD |
|
|
Term
| what allows lipoamide to move between different active sites? |
|
Definition
|
|
Term
| depiction of the structure of the pyruvate dehydrogenase complex |
|
Definition
| [image]
-has 8 E2 (α3) trimers at the core to make a hollow cube
-the cube is surrounded by 12 E3 (αβ) dimers and 24 E1 (α2β2) |
|
|
Term
| depiction of the structure of the E2 within the pyruvate dehydrogenase complex |
|
Definition
[image]
contains 8 trimers |
|
|
Term
| depiction of the domains within each E2 (α3) trimer |
|
Definition
|
|
Term
| how the pyruvate dehydrogenase (PDH) complex differs in mammals |
|
Definition
| the core contains another protein, E3-binding protein (E3-BP) |
|
|
Term
| depiction of the reactions of the pyruvate dehydrogenase (PDH) complex |
|
Definition
|
|
Term
| what happens when the pyruvate dehydrogenase (PDH) complex is missing the E3-binding protein (E3-BP)? |
|
Definition
| the PDH complex has greatly reduced activity |
|
|
Term
| how do the 3 distinct active sites of the PDH complex work in concert? |
|
Definition
| the flexible lipoamide arm of the E2 subunit carries substrate from active site to active site |
|
|
Term
|
Definition
| oxidative decarboxylation of pyruvate to acetyl CoA |
|
|
Term
| 2 principal fates of the carbons in acetyl CoA |
|
Definition
| 1: oxidation to CO2 by the citric acid cycle with the concomitant generation of energy
2: incorporation into lipid, because acetyl CoA is an essential precursor for lipid synthesis |
|
|
Term
| simple depiction of the conversion of glucose to pyruvate to acetyl CoA to CO2 and fatty acids |
|
Definition
|
|
Term
| the key means of regulation of the PDH complex in eukaryotes |
|
Definition
| covalent modification in the form of phosphorylation |
|
|
Term
| what phosphorylation does to the PDH complex |
|
Definition
|
|
Term
| what dephosphorylation does to the PDH complex |
|
Definition
|
|
Term
|
Definition
| catalyzes phoisphorylation of PDH complex to deactivate it |
|
|
Term
|
Definition
| catalyzes dephosphorylation of PDH complex to reactivate it |
|
|
Term
| depiction of the regulation of the PDH complex |
|
Definition
|
|
Term
| PDH phosphatase is activated by... |
|
Definition
|
|
Term
| depiction of PDH regulation under high energy charge |
|
Definition
|
|
Term
| depiction of PDH regulation under low energy charge |
|
Definition
|
|
Term
|
Definition
| carbon compounds capable of being oxidized |
|
|
Term
| the function of the citric acid cycle |
|
Definition
| the harvesting of high energy electrons from carbon fuels |
|
|
Term
| how the citric acid cycle begins |
|
Definition
| the 2-carbon acetyl unit condenses with a 4-carbon oxaloacetate to yield the 6-Carbon tricarboxylic acid citrate |
|
|
Term
| simple depiction of an overview of the citric acid cycle |
|
Definition
|
|
Term
| oxidative phosphorylation |
|
Definition
| forming ATP by by the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers |
|
|
Term
|
Definition
| series of membrane proteins electrons from NADH or FADH2 floe thru to generate proton gradient |
|
|
Term
| what proton gradient is used for |
|
Definition
| to generate ATP from ADP and inorganic phosphate |
|
|
Term
| the stagers of cellular respiration |
|
Definition
1: citric acid cycle
2: oxidative phosphorylation |
|
|
Term
| depiction of cellular respiration |
|
Definition
|
|
Term
| the 2 stages of the citric acid cycle |
|
Definition
1: oxidizing 2 carbon atoms to gather energy rich electrons
2: regenerating oxaloacetate and harvesting energy rich electrons |
|
|
Term
| oxidative decarboxylation |
|
Definition
| citrate being oxidized by releasing 2 CO2 to yield a 4-carbon molecule and high transfer potential electrons captured as 2 molecules of NADH |
|
|
Term
| how the citric acid cycle begins |
|
Definition
| joining of 4-Carbon oxaloacetate with the 2-carbon acetyl group acetyl CoA to form citryl CoA, which gets hydrolyzed to form citrate |
|
|
Term
| depiction of the formation of citrate |
|
Definition
[image]
citrate synthase involved in both steps |
|
|
Term
|
Definition
| catalyzes the merging of 4-carbon oxaloacetate to the 2-carbon acetyl group to form citrate |
|
|
Term
|
Definition
| enzyme that catalyzes a synthetic rxn in which 2 subunits are joined usually without the direct participation of ATP or another nucleoside triphosphate |
|
|
Term
| this powers the synthesis of citrate |
|
Definition
| the hydrolysis of the thioester in citryl CoA |
|
|
Term
| composition of mammalian citrate synthase |
|
Definition
| dimer of identical 49-kDa subunitswith a cleft present between the large and small domains of the subunits, adjacent to the subunit interface |
|
|
Term
| the reason for ordered binding in citrate synthase |
|
Definition
| because oxaloacetate induces a major structural rearrangement leading to the creation of a binding site for acetyl CoA |
|
|
Term
| depiction of the structure of citrate synthase |
|
Definition
|
|
Term
| how the wasteful hydrolysis of acetyl CoA is prevented |
|
Definition
| because citrate synthase is well suited for the hydrolysis of citryl CoA but not acetyl CoA |
|
|
Term
| why citrate is isomerized into isocitrate |
|
Definition
| because the hydroxyl (-OH) group in citrate is not properly located in the molecuule for the oxidative decarboxylations that follow |
|
|
Term
| how citrate is isomerized into isocitrate |
|
Definition
| dehydrateion, then hydration |
|
|
Term
|
Definition
| catalyzes isomerization of citrate into isocitrate |
|
|
Term
| depiction of how citrate is isomerized into isocitrate |
|
Definition
[image]
aconitase involved in both steps |
|
|
Term
|
Definition
| catalyzes the oxidative decarboxylation of isocitrate to α-ketoglutarate |
|
|
Term
| net rxn that oxidizes and decarboxylates isocitrate to α-ketoglutarate |
|
Definition
| isocitrate + NAD+ --> α-ketoglutarate + CO2 + NADH |
|
|
Term
| depiction of the oxidative decarboxylation of isocitrate to α-ketoglutarate |
|
Definition
[image]
catalyzed by isocitrate dehydrogenase |
|
|
Term
| depiction of the oxidative decarboxylation of α-ketoglutarate |
|
Definition
|
|
Term
| α-ketoglutarate dehydrogenase complex |
|
Definition
catalyzes the oxidative decarboxylation of α-ketoglutarate
structurally similar to PDH |
|
|
Term
| how the citric acid cycle produces ATP |
|
Definition
| the cleavage of the thioester of succinyl CoA is coupled with the phosphorylation of ADP |
|
|
Term
| succinyl CoA synthetase (succinate thiokinase) |
|
Definition
| catalyzes the cleavage of the thioester of succinyl CoA that gets coupled with the phosphorylation of ADP |
|
|
Term
| depiction of the cleavage of the thioester of succinyl CoA that gets coupled with the phosphorylation of ADP to yield ATP |
|
Definition
[image]
catalyzed by succinyl CoA synthetase (succinate thiokinase) |
|
|
Term
| the 2 forms of succinyl CoA synthetase (succinate thiokinase) in mammals |
|
Definition
1: ADP acceptor
2: GDP acceptor |
|
|
Term
| tissue where the ADP accepting version of succinyl CoA synthetase (succinate thiokinase) dominates in mammals |
|
Definition
| tissues that perform lost of cellular respiration, such as skeletal and heart muscle |
|
|
Term
| tissue where the GDP accepting version of succinyl CoA synthetase (succinate thiokinase) dominates in mammals |
|
Definition
| tissues that perform lost of anabolic rxns, such as liver |
|
|
Term
| how the GDP-requiring form of succinyl CoA synthetase (succinate thiokinase) is believed to work |
|
Definition
| in reverse of the direction observed in the citric acid cycle; that is, GTP is used to power the synthesis of succinyl CoA, which is a precursor for heme synthesis |
|
|
Term
| substrate-level phosphorylation |
|
Definition
| generation of ATP a rxn in which a high-phosphoryl-transfer-potential compound (succinyl phosphate) transfers the phosphate to ADP to generate ATP |
|
|
Term
| types of rxns glycolysis uses to form ATP |
|
Definition
| substrate-level phosphorylation rxns |
|
|
Term
| depiction of the rxn mechanism of succinyl CoA synthetase |
|
Definition
|
|
Term
| how oxaloacetate is regenerated |
|
Definition
| by the oxidation of succinate |
|
|
Term
| depiction of the oxidation of succinate |
|
Definition
|
|
Term
| how succinate is oxidized to regenerate oxaloacetate |
|
Definition
1: oxidation
2: hydration
3: 2nd oxidation |
|
|
Term
|
Definition
| catalyzes the oxidation of succinate to fumarate |
|
|
Term
| depiction of the function of succinate dehydrogenase |
|
Definition
|
|
Term
| how succinate dehydrogenase differs from other enzymes in the citric acid cycle |
|
Definition
| it is embedded in the inner mitochondrial membrane in association with the electron transport chain, which is also set in the inner mitochondrial membrane |
|
|
Term
| the link between the citric acid cycle and ATP formation |
|
Definition
| the electron transport chain |
|
|
Term
|
Definition
| catalyzes hydration of fumarate to form L-malate |
|
|
Term
| depiction of the function of fumarase |
|
Definition
|
|
Term
|
Definition
| catalyzes oxidation of malate to form oxaloacetate |
|
|
Term
| depiction of the function of malate dehydrogenase |
|
Definition
|
|
Term
| how the energetically unfavorable oxidation of malate is driven |
|
Definition
| driven by the use of the products; oxaloacetate by citrate synthase and NADH by the electron-transport chain |
|
|
Term
| the net rxn of the citric acid cycle |
|
Definition
| acetyl CoA + 3 NAD+ + FAD + ADP + pi + 2 H2O --> 2 CO2 + 3 NADH + FADH2 + ATP + 2 H+ + CoA |
|
|
Term
| depiction of the complete citric acid cycle |
|
Definition
|
|
Term
|
Definition
| rxn products passing directly from one active site to the nest thru connecting channels |
|
|
Term
| the key catabolic function of the citric acid cycle |
|
Definition
| the production of high energy electrons in the form of NADH and FADH2 |
|
|
Term
| does molecular oxygen participate directly in the citric acid cycle? |
|
Definition
|
|
Term
| why the citric acid cycle operates only under aerobic conditions |
|
Definition
| because NAD+ and FAD can be regenerated in mitochondria only by the transfer of electrons to molecular oxygen |
|
|
Term
| how NAD+ and FAD can be regenerated in mitochondria |
|
Definition
| only by the transfer of electrons to molecular oxygen |
|
|
Term
| why glycolysis can proceed under anaerobic conditions |
|
Definition
| because NAD+ is regenerated in the conversion of pyruvate into lactate or ethanol |
|
|
Term
| depiction of the control of the citric acid cycle |
|
Definition
|
|
Term
| the primary control points to control the rate of the citric acid cycle |
|
Definition
-isocitrate dehydrogenase
-α-ketoglutarate dehydrogenase |
|
|
Term
| the citric acid cycle is regulated primarily by the concentrations of... |
|
Definition
|
|
Term
| something succinyl CoA from the citric acid cycle is used to make |
|
Definition
| the heme groups of hemoglobin and myoglobin |
|
|
Term
| something α-ketoglutarate from the citric acid cycle is used to make |
|
Definition
|
|
Term
| something oxaloacetate from the citric acid cycle is used to make |
|
Definition
|
|
Term
| depiction of the biosynthetic roles of the citric acid cycle |
|
Definition
|
|
Term
| when the citric acid cycle creates intermediates for biosynthesis |
|
Definition
| when the energy needs of the cell are met |
|
|
Term
| how are citric acid cycle intermediates replenished when they are drawn out for biosynthesis |
|
Definition
| conversion of pyruvate to oxaloacetate |
|
|
Term
|
Definition
| catalyzes the conversion of pyruvate to oxaloacetate |
|
|
Term
| rxn that converts pyruvate to oxaloacetate |
|
Definition
| pyruvate + CO?2 + ATP + H2O --> oxaloacetate + ADP + Pi + 2 H+ |
|
|
Term
| depiction of pyruvate carboxylase replenishing the citric acid cycle |
|
Definition
|
|
Term
| when pyruvate carboxylase is active |
|
Definition
| only in the presence of acetyl CoA |
|
|
Term
| what happens to oxaloacetate when the energy charge is high? |
|
Definition
| oxaloacetate gets converted into glucose |
|
|
Term
| what happens to oxaloacetate when the energy charge is low? |
|
Definition
| oxaloacetate replenishes the citric acid cycle |
|
|
Term
|
Definition
| rxn that leads to the net synthesis, or replenishment, of pathway components |
|
|
Term
| example of an anaplerotic rxn |
|
Definition
| synthesis of oxaloacetate by the carboxylation of pyruvate |
|
|
Term
| the fate of acetyl CoA that enters the citric acid cycle |
|
Definition
|
|
Term
| what the glyoxylate cycle enables plants and bacteria to do |
|
Definition
| convert fats into carbohydrates |
|
|
Term
| some ways the glyoxylate cycle differs from the citric acid cycle |
|
Definition
-bypasses the 2 decarboxylation steps of the cycle
-2 acetyl CoA's enter the cycle instead of just 1 |
|
|
Term
|
Definition
| cleaves isocitrate into succinate and glyoxylate |
|
|
Term
|
Definition
| catalyzes the condensation of acetyl CoA with glyoxylate to form malate |
|
|
Term
| depiction of the glyoxylate pathway |
|
Definition
|
|
Term
|
Definition
| organelles in plants where the glyoxylate pathway takes place |
|
|
Term
| electron transport chain aka respiratory chain |
|
Definition
| 4 large protein complexes that are embedded in the inner mitochondrial membrane |
|
|
Term
| where the electron transport chain is located |
|
Definition
| inner mitochondrial membrane |
|
|
Term
|
Definition
| generation of high-transfer-potential electrons by the citric acid cycle, the respiratory chain, and the accompanying synthesis of ATP |
|
|
Term
| depiction of a simple overview of oxidative phosphorylation |
|
Definition
|
|
Term
| where the flow of electrons thru the electron transport chain takes place |
|
Definition
| inner mitochondrial membrane |
|
|
Term
|
Definition
| folds in the mitochondrion's inner membrane |
|
|
Term
| the 2 compartments of the mitochondrion |
|
Definition
1: intermembrane space
2: matrix |
|
|
Term
| permeability of the mitochondrion's outer membrane |
|
Definition
|
|
Term
| why the mitochondrion's outer membrane is very permeable |
|
Definition
| because it contains many mitochondrial porins, which create pores |
|
|
Term
| function of mitochondrial porin |
|
Definition
| regulates flux of molecules crucial to the function of cellular respiration |
|
|
Term
| permeability of mitochondrion's inner membrane |
|
Definition
| intrinsically permeable to nearly all ions and polar molecules |
|
|
Term
|
Definition
| inside mitochondrion's inner membrane |
|
|
Term
|
Definition
| intermembrane space in mitochondrion; called this because it is freely accessible to most small molecules in the cytoplasm cytoplasm |
|
|
Term
| simple depiction of the anatomy of a mitochondrion |
|
Definition
|
|
Term
| what oxidative phosphorylation does to O2 |
|
Definition
|
|
Term
| how oxidative phosphorylation reduces O2 to water |
|
Definition
| using electrons from NADH and FADH2 |
|
|
Term
|
Definition
| set of membrane proteins in which the transfer of electrons to reduce O2 to water takes place |
|
|
Term
| a conversion of potential that occurs in oxidative phosphorylation |
|
Definition
| the electron-transfer potential of NADH or FADH2 being converted into the phosphoryl-transfer potential of ATP |
|
|
Term
| how phosphoryl-transfer potential is expressed |
|
Definition
|
|
Term
|
Definition
| expression for electron transfer potential |
|
|
Term
| how reduction potential is expressed |
|
Definition
|
|
Term
|
Definition
| substance that exists as oxidized and reduced forms |
|
|
Term
| how the reduction potential of a redox couple is determined |
|
Definition
| by measuring the electromotive force generated by a sample half cell connected to a standard reference half cell |
|
|
Term
| depiction of how redox potential is measured |
|
Definition
[image]
electrons flow thru the wire and ions flow thru the agar bridge |
|
|
Term
| the reduction potential of the X:X- couple |
|
Definition
| the observed voltage at the start of the experiment |
|
|
Term
| the reduction potential of the H+:H2 couple |
|
Definition
|
|
Term
| what a positive reduction potential (ΔE0') indicates |
|
Definition
|
|
Term
| what a negative reduction potential (ΔE0') indicates |
|
Definition
|
|
Term
|
Definition
| faraday proportionality constant (96.48 kJ mol-1 V-1, or 23.06 kcal mol-1 V-1) |
|
|
Term
| relationship between ΔE0' and ΔG°' |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| the driving force of oxidative phosphorylation |
|
Definition
| the electron-transfer potential of NADH or FADH2 relative to that of O2 |
|
|
Term
| where does the energy that produces the proton gradient to make ATP come from? |
|
Definition
| the energy released by the reduction of each electron carrier |
|
|
Term
|
Definition
| supramolecular complex composed of complexes that carries electrons down the electron transport chain |
|
|
Term
| depiction of the components of the electron transport chain |
|
Definition
|
|
Term
| why FADh2 derived electrons pump fewer protons and ATP than NADH derived electrons |
|
Definition
| electrons from FADH2 feed into the chain downstream from those from NADH because those from FADH2 have lower reduction potential |
|
|
Term
| why electrons from FADH2 feed into the chain downstream from those from NADH |
|
Definition
| because those from FADH2 have lower reduction potential |
|
|
Term
| the 2 types of Fe proteins in the electron transport chain |
|
Definition
1: iron-sulfur proteins aka nonheme-iron proteins
2: cytochromes, which are components of heme prothetic groups |
|
|
Term
|
Definition
| Fe containing protein that is a component of a heme prosthetic group |
|
|
Term
| another metal that can participate in the electron transport chain |
|
Definition
|
|
Term
| how electron transfer works for quinones |
|
Definition
| for quinones, electron-transfer rxns are coupled to proton binding and release |
|
|
Term
| how the electron transport chain creates a proton gradient |
|
Definition
| electron flow within it leads to the transport of protons accross the inner membrane |
|
|
Term
| a protein complex that does not pump electrons |
|
Definition
|
|
Term
| where the electrons from NADH enter the electron transport chain |
|
Definition
| at NADH-Q oxidoreductase (complex 1) |
|
|
Term
| depiction of the electron transport chain's complexes |
|
Definition
|
|
Term
| depiction of coupled electron-proton transfer rxns thru NADH-Q oxidoreductase |
|
Definition
|
|
Term
|
Definition
| funnels electrons from a 2 electron carrier to a 1 electron carrier and pumps protons |
|
|
Term
|
Definition
| the mechanism for the coupling of electron transfer from Q to cytochrome C to transmembrane proton transport |
|
|
Term
|
Definition
|
|
Term
| depiction of the cytochrome oxidase mechanism |
|
Definition
|
|
Term
| depiction of proton transport by cytochrome c oxidase |
|
Definition
|
|
Term
| depiction of the electron-transport chain |
|
Definition
|
|
Term
| some dangerous radicals that can form from O2 |
|
Definition
| -superoxide (O2-)
-peroxide (O22-) |
|
|
Term
|
Definition
| -superoxide (O2-)
-peroxide (O22-)
-hydroxyl radical (OH•) |
|
|
Term
| some things reactive oxygen species can cause |
|
Definition
-aging
-some other diseases |
|
|
Term
|
Definition
| catalyzes the conversion of 2 superoxides into hydrogen peroxide and molecular oxygen |
|
|
Term
| depiction of the function of superoxide dismutase |
|
Definition
|
|
Term
|
Definition
| catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen |
|
|
Term
| depiction of the function of catalase |
|
Definition
|
|
Term
|
Definition
| rxn in which a single reactant is converted into 2 different products |
|
|
Term
|
Definition
| protein protons move thru to generate ATP |
|
|
Term
|
Definition
proposes that electron transport and ATP synthesis are coupled by a proton gradient across the inner mitochondrial membrane
basically says that flow of protons drives production of ATP by ATP synthase |
|
|
Term
| how electron transport and ATP synthesis are coupled |
|
Definition
| by a proton gradient across the inner mitochondrial membrane |
|
|
Term
| depiction of the chemostatic hypothesis |
|
Definition
|
|
Term
|
Definition
| the energy rich, unequal distribution of protons across the inner mitochondrial membrane |
|
|
Term
| the 2 components of the proton motive force |
|
Definition
1: chemical gradient
2: charge gradient |
|
|
Term
| chemical gradient for protons |
|
Definition
| can be represented as a pH gradient |
|
|
Term
|
Definition
| created by the positive charge on the unequally distributed protons forming the chemical gradient |
|
|
Term
| how protons are transported out of the matrix into the intermembrane space |
|
Definition
| electron transfer thru the respiratory chain leads to the pumping of protons |
|
|
Term
| how to calculate proton-motive force |
|
Definition
| proton-motive force (Δp) = chemical gradient (ΔH) + charge gradient (Δψ) |
|
|
Term
| the respiratory chain and ATP synthase are biochemically separate. what links them? |
|
Definition
| only the proton-motive force |
|
|
Term
| depiction of the link between the respiratory chain and ATP synthase |
|
Definition
|
|
Term
| how NADH oxidation is coupled to ATP synthesis |
|
Definition
1: electron transport generates a proton-motive force
2: ATP synthesis by ATP synthase is powered by a proton-motive force |
|
|
Term
| depiction of ATP synthase |
|
Definition
|
|
Term
| what makes each of the 3 β subunits different? |
|
Definition
| they each interact with a different face of the γ subunit |
|
|
Term
| how formation of cristae makes ATP synthesis more efficient |
|
Definition
| localizing the proton gradient to where the ATP synthases are |
|
|
Term
| depiction of how ATP synthase assists in the formation of cristae |
|
Definition
|
|
Term
| the rxn ATP synthase catalyzes |
|
Definition
| formation of ATP from ADP and orthophosphate
ADP3- + HPO42- + H+ <--> ATP4- + H2O |
|
|
Term
| the 3 different functions performed by the 3 active sites in ATP synthase |
|
Definition
| 1: trapping of ADP and Pi
2: ATP synthesis
3: ATP release and ADP and Pi binding |
|
|
Term
| the 2 parts of ATP synthase |
|
Definition
1: moving unit (rotor) consisting of c ring and γε stalk
2: the stationary unit (stator) consisting of the remainder of the molecule |
|
|
Term
| depiction of the distinct ATP synthase nucleotide-binding sites |
|
Definition
|
|
Term
| order in which subunits of ATP synthase change state |
|
Definition
T --> O --> L
repeatedly rotates counterclockwise |
|
|
Term
| depiction of a binding-change mechanism for ATP synthase |
|
Definition
|
|
Term
| what drives the rotation of the γ subunit in ATP synthase? |
|
Definition
|
|
Term
| depiction of the components of the proton-conducting unit of ATP synthase |
|
Definition
|
|
Term
| what powers the rtation of the c ring in ATP synthase? |
|
Definition
| movement of protons thru the half channels from high proton c'tration of intermembrane space to low proton c'tration of matrix |
|
|
Term
| depiction of proton motion across the membrane |
|
Definition
|
|
Term
| depiction of the proton path thru the membrane |
|
Definition
|
|
Term
| number of c subunits in ring vs. efficiency of ATP synthase |
|
Definition
| the more subunits in the ring, the less efficient, that is, the more protons needed to synthesize 1 ATP |
|
|
Term
| depiction of an overview of oxidative phosphorylation |
|
Definition
|
|
Term
| how electrons from intermembrane space enter matrix |
|
Definition
|
|
Term
| how NADH is reoxidized to NAD+ |
|
Definition
| electrons from NADH, rather than NADH itself, are carried across the mitochondrial membrane |
|
|
Term
| the glycerol 3-phosphate shuttle |
|
Definition
| introduces electrons from NADH into the electron transport chain |
|
|
Term
| depiction of the glycerol 3-phosphate shuttle |
|
Definition
|
|
Term
|
Definition
| transfers electrons from NADH to oxaloacetate, forming malate |
|
|
Term
| depiction of the malate-aspartate shuttle |
|
Definition
|
|
Term
| the major function of oxidative phosphorylation |
|
Definition
|
|
Term
|
Definition
| transports ATP out of matrix and ADP into matrix |
|
|
Term
| when ATP enters the mitochondrial matrix |
|
Definition
|
|
Term
| when ADP enters the mitochondrial matrix |
|
Definition
|
|
Term
| depiction of the mechanism of ATP-ADP translocase |
|
Definition
|
|
Term
|
Definition
| large complex of proteins that provide the substrates needed for ATP synthesis |
|
|
Term
| depiction of the mitochondrial transporters |
|
Definition
|
|
Term
| cellular respiration is regulated by... |
|
Definition
| the need for ATP, since it's the ultimate and product of cellular respiration |
|
|
Term
| how many molecules of ATP are formed when glucose is completely oxidzed to co2? |
|
Definition
|
|
Term
| which step of cellular respiration generates most of the ATP? |
|
Definition
| oxidative phosphorylation (26 of 30) |
|
|
Term
| how many ATP does anaerobic glycolysis yield? |
|
Definition
|
|
Term
| the rate of oxidative phosphorylation is determined by... |
|
Definition
|
|
Term
| when electrons flow thru the electron transport chain to O2 |
|
Definition
| they usually do this only when ADP is simultaneously phosphorylated to ATP |
|
|
Term
| respiratory control or acceptor control |
|
Definition
| regulation of the rate of oxidative phosphorylation by the ADP level |
|
|
Term
| when electrons flow from fuel molecules to O2 |
|
Definition
| only when ATP needs to be synthesized |
|
|
Term
| depiction of how energy charge regulates the use of fuels |
|
Definition
|
|
Term
| depiction of some things proton gradient can be used for |
|
Definition
|
|
