midterm 3 (metabolic pathways)

pyruvate, HETPP, acetyl-CoA

pyruvate dehydrogenase rxn: TPP (thiamine) decarboxylates ____ and interacts w remainder of molec to form _____ (E2), which then becomes _______, before the E2 swinging arm is oxidized/regenerated

flavin, N

pyruvate dehydrogenase: FAD is an electron carrier with its business end being a _______ (3-ring structure w 2 ____'s as reactive sites)

lipoamide, E3

pyruvate dehydrogenase: ______ has a 5-membered ring w 2 S's and can carry/pass along an acetyl group. Different swinging arms can pass acetyl groups to each other until they reach ____ units

substrate, futile, amplifies

reciprocal regulation of the catabolic and anabolic enzymes in a ______ cycle 1) helps prevent _____ cycles AND 2) _____ the magnitude of the changes in metabolic flux produced by such regulation

iron sulfur clusters

these are found in electron transport complexes; they can accept and then give up one electron at a time

coupled rxns

these are reactions that are forced by the enzymatic mechs of metabolism to occur together — one cannot occur w/o the other also occurring

slow, enzyme

under biol conditions, rxns are ____ (slow/fast); cells control which rxns occur and how fast via ______ catalysis

biotin

a coenzyme that carries activated carboxyl groups, often used by carboxylase enzymes

thiamine

a coenzyme used to decarboxylate a molecule and then transfer the remainder of the molecule onto an acceptor

aldol cleavage

a common rxn type in metabolism that breaks a C-C bond to generate alcohol and aldehyde groups at the two new ends generated from the cleaved bond

coenzyme Q

a lipid-soluble small molecule dissolved in the hydrophobic core of the inner mitochondrial membrane that ferries electrons from complexes I and II to complex III.

reduction potential

a measure (in units of volts) of the affinity of various molecules for electrons. Oxidation/reduction reactions have a negative free energy when electrons pass from a molecule with a more negative reduction potential to one with a more positive reduction potential

energy charge

a measure of current ability of the cell to supply ATP. Decrease in this is typically sensed by an increase of [ADP] and/or [AMP], as these quantities inc substantially before large decreases in [ATP] occur

glyoxylate cycle

a modified citric acid cycle that can occur in plants and bacteria and allows them to carry out a net conversion of fatty acids to carbohydrates, something mammalian metabolism cannot do

pyruvate dehydrogenase

a multi-enzyme complex found in mitochondria that catalyzes a 5-step reaction that bridges btw glycolysis and the citric acid cycle

enzymatic, series

a pathway is a set of _______ reactions that function in a _______ to do something, such as convert a starting molecule into a product

7.3

a phosphoanhydride bond is occurs btw two adjacent phosphate groups. ATP has two of these bonds. These bonds have a relatively high standard free energy of hydrolysis (~_____ kcal/mol)

regulation

mechs that control an individual metabolic pathway

integration

mechs that coordinate the regulation of different metabolic pathways

3, AMP, fats, carbohydrates

ATP consists of adenine plus a sugar and _____ phosphates. _____ has only 1 phosphate. ATP is only for immediate energy exchange (short half-life), whereas long-term energy storage is left to ____ (e.g. triacylglycerols) or ____ (glycogen)

antiporter, electrical, negative, symport, chemical

ATP made in the mitochondria gets out via an _______ (antiporter/symporter) that is driven by the ______ (chemical/electrical) component of the electrochem gradient due to the matrix and ATP being more _____ in charge than the intermembrane space and ADP, respectively. Protons and phosphate enter the matrix via _____ (symport/antiport) and are driven by the ______ (chemical/electrical) component due to low conc within the matrix

3, conformations, H+

ATP synthase, binding change model: in the lollipop head there are ____ alpha beta pairs, with each in slightly different _____. ______ passage makes gamma spin within the alpha beta head. There is rotation thru conformations allowing synthesis and release of ATP.

rotor, alpha, inside

ATP synthase: a _____ (power from the bottom of the molec) causes spinning of ____ helices inside the synthase head. In mitochondria, the head points (inside/outside) the intermembrane space

transition

ATP synthase: after binding ADP and Pi, the _____ state is stabilized for phosphoanhydride bond formation; then ATP is released

1, IV, +2

Cu ions carry only ____ electron and are located in complex ____. These alternate between the +1 and ______ ox states

ADP, AMP

Decrease in energy charge is typically sensed by an increase of [_____] and/or [_____], as these quantities inc substantially before large decreases in [ATP] occur

flavin

FMN, located in complex _____ of the electron transport chain has a _____ as its business end and is stable enough to carry either 1 (despite the radical) or 2 electrons

cofactors

In citric acid cycle, 1 GTP is made, but more imp lots of reduced ______ are produced, which can be converted into lots of ATP

nucleotides, hydride, transfer

NAD+ consists of 2 _______ with the one that has a (+) charge as the reactive site. NAD+ accepts a ____ ion (2 electrons and a proton). NAD+ can accept 2 electrons from compounds that have a higher electron _____ potential

ethanol, co2, lactate, o2

NAD+ regeneration: in anaerobic conditions, NAD+ is regenerated and _____ + _____ (gas) are produced in yeast AND _______ is produced in humans; in aerobic conditions, NADH reduces ____, which regenerates NAD+

feedback, feed-forward

_____ inhibition and _____ activation are typically used to coordinate the regulation of non-equil rxns in a metabolic pathway so that flux can be regulated while maintaining homeostasis

intermembrane, Fe-S, c, bL, bH, Q

Q cycle: a QH2 is oxidized near the _______ (intermembrane/matrix) side of complex III. This allows for release of protons to that side. One electron released goes to _____ then cyt ____. The other goes to ____ then ____ (near the matrix side) until it finally ends up on _____. The oxidation of a second QH2 is the same, except the final electron acceptor on the matrix side is the Q radical from step 1. The final acceptor also picks up 2 protons

substrate, ox

______-level phosphorylation and ______ phosphorylation are 2 diff ways that energy captured from catabolism is used to synthesize ATP

lipoamide

a coenzyme in pyruvate dehydrogenase that accepts an acetyl group, and then transfers it to coenzyme A.

iron-sulfur, I-III, +3

_______ clusters carry only 1 electron and are located in complexes _____. ____ atoms are coordinated by S atoms (Cys side chains or free sulfide) and are btw the +2 and ____ state in a conjugated system

enzyme

a coenzyme is a small molecule that helps an _____ work

electrochemical gradient

a proton gradient across the inner mitochondrial membrane that stores energy in both an electrical voltage (0.14 V more positive outside) across the membrane and in a chemical concentration gradient of protons (pH is 1.4 units lower outside) across the membrane

feed-forward activation

a regulatory strategy in which a metabolite activates activity of a non-equilibrium enzyme that acts somewhere downstream in a pathway that consumes that metabolite, thus helping to hold [metabolite] at a constant homeostatic concentration

feedback inhibition

a regulatory strategy in which a metabolite inhibits activity of a non-equil enzyme that acts somewhere upstream in a pathway that produces that metabolite, thus helping to hold the [metabolite] at a constant homeostatic conc

pathway

a set of enzymatic reactions that function in a series to do something, such as convert a starting molecule into a product

futile cycle

a set of metabolic rxns that send molecules thru a series of intermediates and finally back to the original molecules, consuming energy in the process w/o producing anything useful

substrate cycle

a set of rxns that use one set of enzymes to convert metabolite A to metabolite B, and different enzymes to convert B back to A

thioester bond

a single bond from a carbonyl C to a S atom, as found fo example in acetyl coenzyme A. Has a relatively high standard free energy of hydrolysis (~7.5 kcal/mol)

vitamin

a small molecule needed for life that we cannot synthesize and thus require it in our diet. These are often coenzymes or components of coenzymes

coenzyme

a small molecule that helps an enzyme work

Schiff, electron, second

aldolase aldol cleavage involves a _____ base that acts as an _____ sink to assist C-C bond cleavage, which is why it's important to have the carbonyl on the ____ C so it can interact with the base

synthesis

an H+ gradient is sufficient to drive ATP _____ (the lollipop head side is the side where ATP is produced)

dehydrogenase

an enzyme that catalyzes an ox/red rxn

isomerase

an enzyme that rearranges a molec without adding or removing any atoms

mitochondrion, matrix, O2

an organelle found in eukaryotic cells that carries the machinery of ox phosphorylation in a series of multienzyme complexes embedded in the inner of its two membranes. The citric acid cycle occurs in its _______. The inner membrane is only permeable to _____

prochiral, 3

citrate has a previously unrecognized type of symmetry. It has a _____ C — as long as the enzyme contacts at ____ sites of the substrate, the molec is distinguishable (only doing rxn on pro-R group)

catalytically

citric acid cycle intermediates act ________ (they're regenerated and stay at the same conc)

substrates, pyruvate dehydrogenase, O2

citric acid cycle regulation: flux mainly det by availability of _____ (acetyl CoA, NAD+, FAD). Acetyl CoA comes from ________; NAD+ and FAD avail depends on their regeneration by ox phosphorylation, which requires ____. Within cycle regulation occurs at the three non-equil rxns

sulfhydryl, acetyl, thioester, hydrolysis

coenzyme A has a long handle with a ______ at its reactive site where it can pick up an _____ unit and attach to it via a _____ bond, which has a large energy of ____ (-7.5 kcal/mol). The group can be transferred to other molec

QH2, I, II, III

coenzyme Q and _____ can float free in the lipid bilayer and ferry electrons from complexes ____ and _____ to complex ______. Q can carry either 1 or 2 electrons (tho 1 electrons gives a radical and a negative charge). Q has a ring with 2 carbonyls attached to a long hydrophobic tail

electrons, O2, synthesis

control of ox phosphorylation (limiting flux) occurs via having a source of ______ (NADH); having a sink for electrons (____); and having substrates for ATP _____

reciprocally

corresponding catabolic and anabolic pathways are typically _______ regulated to prevent futile cycles

intermediate, transfer, thermodynamically

coupling of two reactions (as occurs in the glyceraldehyde 3-phosphate reaction in glycolysis) often involves using the first reaction to generate an _____ with a high group-______ potential, and then using this potential to ______ drive the second reaction

peripheral, III, IV, don't

cytochrome c is a _______ membrane protein that shuttles electrons btw complexes ____ and _____. Fe is liganded by His and Met side chains. Importantly, electron carriers ____ (do/don't) need to contact to transfer electrons

1, III and IV, cytochrome c

cytochromes carry ____ electron and are located in complexes ____ and _____, and are small proteins with bound heme. Hemes differ in side-chain structure, being covalently bound to protein, and the protein environment

glycerol phosphate, FAD, Q, III

cytosolic NADH made by glycolysis donates electrons to the mitochondrial electron transport chain via a _______ shuttle that passes electrons to _____, which gives 2 electrons to _____, which then passes the electrons to complex ______

amphibolic

describes a pathway (such as the citric acid cycle) that is used for both catabolic and anabolic purposes

prochiral

describes asymmetry of a C atom that makes single bonds to four substituent chemical groups, two of which are identical. Enzymes have the ability to distinguish btw the 2 identical substituents by recognizing subtle asymmetry of such an arrangement

catabolic

describes metabolic rxns that break larger molecs down to smaller ones

anabolic

describes metabolic rxns that build larger molecules from smaller ones

ox

electron transfer potential is the energy released when a molecule is ______ (ox/red)

dissipation, DNP

electron transport and ATP synthesis are coupled. You can't have transport without ATP bc ATP allows for _______ of the proton gradient, which would otherwise be very unfavorable for proton pushing into an already stark gradient. When one adds _______, it creates a leaky membrane, allowing protons to flow

coupled

electron transport and ATP synthesis in the mitochondria are ______, meaning one cannot occur without the other

thioester, cysteine

energy coupling of glyceraldehyde 3-phosphate dehydrogenase involves a ____ bond forming with a _____ (name aa). This high energy bond is later captured in a bond with a high energy phosphoryl group

kinase

enzyme that catalyzes transfer of a phosphoryl group btw ATP and another molec

FAD

flavin adenine dinucleotide, an electron carrier that functions similarly to NAD+

supply, insulin, enzymes, allosteric, phosphorylation, amount

flux thru glycolysis can be limited via ____ of accessible glucose (this can happen via ____ which regulates the amount of transporter on the cell surface that allows glucose entry) and capacity of glycolytic _____ to process glucose — coordinately increasing activity of all 3 in glycolysis leads to a large effect (this can be done quickly via ______ effectors or slowly via modifications like ______ or altering the _____ of protein)

regulation

gluconeogenesis regulation: outside the liver with substrate cycles, strong regulation of _____ possible (no gluconeogenesis tho)

energy, 6, 2

gluconeogenesis: reversing glycolysis requires _____ to pump the non-equil steps backwards. ____ ATP equivalents required to drive gluconeogenesis, while glycolysis nets _____ ATP

mitochondria, pyruvate carboxylase, oxaloacetate, biotin, lys, cytosol, PEP carboxykinase

gluconeogenesis: reversing pyruvate kinase entails pyruvate entering the ______, which is where ________ exclusively catalyzes the formation of ______ using ATP. Carboxylases use the coenzyme ______ to carry activated carboxyl groups. This coenzyme is covalently attached to a ____ residue of pyruvate carboxylase with the ring structure as the business end. Its long flexible arm allows for swinging btw two active sites. Oxaloacetate/malate is produced and shuttled back to the ______ (cytosolic NADH also maintained via this shuttle). ______ catalyzes transformation into PEP

oxaloacetate, oxaloacetate

glucose can be formed from ____ in the citric acid cycle. Fatty acids alone cannot be used to achieve net synthesis of carbohydrates, as ______ cannot be sent out of the cycle without something to replenish it

passive, phosphorylated

glucose enters the cell via ______ (passive/active) transporter. When ______, the glucose is no longer the correct substrate

PFK, inhibited, glucose 6-phosphate, activated, fructose 1,6-bisphosphate, ATP

glycolysis homeostasis is maintained bc hexokinase and pyruvate kinase are regulated to match _____. Hexokinase is feedback _____ by _______. Pyruvate kinase is feed-forward _______ by ______, which relieves inhibition by physiological [______].

coordinately, osmotic, intermediates

glycolysis homeostasis: this requires _____ regulating all nonequil rxns at the same time. Intermediates must be maintained at constant levels so as not to cause _____ problems if [metabolites] fluctuates and so as not to affect _____ in other pathways

citrate, PFK-1, accumulation

glycolysis regulation: _____, a citric acid cycle intermediate, feeds back to allosterically inhibit ______. This is an example of metabolites being fed faster than can be processed, leading to _____ of intermediates, which feedback inhibit to slow down glycolysis and maintain homeostasis

glucagon, kinase, PFK-2, fructose 2,6-bisphosphate, PFK-1, PFK-2

glycolysis regulation: in the liver only, _____ (mammalian hormone signaling low blood [Glc]) can regulate glycolysis via binding to cell surface, activating a protein ____ that phosphorylates and inactivates ______, inhibiting synthesis of ______, a molec that activates _____. Conc levels of the activating molec are dependent on balance btw ____ and phosphatase

PFK, ATP, AMP

glycolysis: ATP and AMP allosterically regulate ________. ______ inhibits, while ______ negates the inhibition. Therefore, the ratio of [AMP]/[ATP] controls this enzyme's activity

allosteric, cooperative, allosteric effectors, lower

glycolysis: PFK is an ______ enzyme and is a tetramer w ______ binding. _______ bind remote from active site, shift equil btw high and low-affinity conformations. When [AMP]/[ATP] is high, _____ (higher/lower) [substrate] is needed to reach 1/2 Vmax of the rxn

committed

glycolysis: PFK regulated bc it's the first _____ step (first non-equil enzyme not also in other pathways). Thus it is also the step regulated by factors besides energy charge

ox, dehydrogenase

glycolysis: energy to generate ATP comes from ______ (ox/red) catalyzed by glyceraldehyde 3-phosphate ______

hydrolyzed, higher, lower

group transfer potential is the energy released when a bond to a chemical group is _____. A chemical group can be transferred from a molecule that has a _____ potential to one with a ______ potential to give a reaction negative standard delta G

metabolites, constant, flux

homeostasis is the concept that living organisms tend to maintain themselves in a constant state. As applied to metabolism, the term is used to mean that _______ tend to be maintained at a ________ concentration despite large changes in metabolic _____

decarboxylated, reduced

in alcoholic fermentation, pyruvate is ______ then _______

anapleurotic, acetyl CoA, pyruvate carboxylase, oxaloacetate

in citric acid cycle, it's necessary to replenish intermediates via ______ rxns. These rxns are activated when there is a build up of _______, which leads to allosteric activation of _______, which in turn generates more _______, allowing replenishing of intermediates

glucose, lactate, ethanol, CO2, NAD+

in fermentation, _____ is anaerobically converted to _____ or _______+_______ (gas) via glycolysis plus add'l steps that allow for recovery of ______ to continue generating energy under anaerobic conditions

glucose, pyruvate

in gluconeogenesis, _____ is generated from _______

glucose, anaerobically, pyruvate, acetyl CoA

in glycolysis, ______ is _____ (aerobically/anaerobically) converted to ______, which is one step short of conversion to ______

2, 4, 2

in glycolysis, the goal is to make ATP. In the process, ____ ATP are invested, _____ are made, and ____ are netted

pyruvate, lactate

in homolactic fermentation, ______ is reduced to _______

reduction, positive, respiratory, reduced, oxidized

in the electron transport chain, electrons flow thru carriers w progressively higher ________ potential (affinity for electrons), meaning the potential becomes more ______ along the chain. The order of the electron chain can be determined via _______ inhibitors, which block the chain, leaving upstream carriers ______ and downstream carriers ______ (ox vs red form can be seen via spectrophotometer as diff colored light)

non-equil, regulated

metabolic pathways have 2 types of reactions 1) equil rxns with delta G near 0 2) non-equil rxns with (-) delta G Flux is limited almost exclusively by the ______ (equil/non-equil) rxns, and the enzymes that cat these rxns are thus ______ to control metabolism

extract, synthesize, far from, intermediates, side, mild

metabolism is a set of chemical rxns that 1) ______ energy from the environment and 2) _____ the molecules necessary for life. Hundreds of rxns occur simult; the system is maintained _____ (far from/near to) equilibrium; rxns are efficient w the accumulation of ______ or _____ products not tolerated; rxns are stereospecific and everything occurs under constant _____ conditions

currencies, coenzyme a, NAD+, ATP

metabolism principles: a few important molecules carry "_______" of metabolism. This facilitates energy exchange. _____ carries acetyl units. ______ carries electrons. _____ carries energy in general.

degradative, futile, enzymes, active

metabolism principles: biosynthetic and _____ pathways are distinct in that they always differ at at least one step to prevent a ______ cycle. At the differing step are distinct _____ that can be separately controlled and are never highly _____ at the same time

requiring, enzymes, thermodynamically, enzyme, speed

metabolism principles: coupled rxns drive energy-______ processes. Importantly, ________ allows all substrates to come together for coupling and therefore makes the net reaction ______ feasible. It follows that regulating the ____ regulates the rxn (_____ control comes from how effective the enzyme is at its job)

regulated, integrated, accessibility, catalytic

metabolism principles: metabolic pathways are ______ (dictates flux) and _______ (coordination of pathways) through varying _____ of substrates, enzymes, enzyme ______ efficiency (via modifications like phosphorylation or allostery)

small, series, captured, one, integration

metabolism principles: metabolic rxns occur in many _____ steps "pathways". 1) the many steps allow for use of many enzymes in ___ for complex transformation 2) energy released at a small step can be _____ efficiently (in ATP) 3) energy can only use _____ energy packet to fuel any small step; but multiple steps can create large transformation 4) many steps allows for ____ of metabolic processes

kinetically

metabolism principles: metabolism is _______ controlled by enzymes

high, rate

metabolism: for equil rxns, enzymes are present at ______ activity, so subtrates and products stay at at equil despite changes in flux. With flux increase and inc in substrate conc, there's also a large _____ inc (usually Km>[substrate]) — same with vice versa: if decrease in flux, dec in [substrate] and rate

can

molecules ______ (can/can't) have a diff red potential depending on the context

complex, intermediates, active, reactive, speed, side

multienzyme complexes can carry out a _____ series of rxns; _____ are channeled from one _____ site to another, which is imp for _____ intermediates (preventing diffusion); these complexes increase _____ and minimize _____ rxns

the Q cycle

name of the mechanism used by complex III to transfer electrons from coenzyme Q to cytochrome c while using the free energy liberated to pump protons out of the mitochondrial matrix.

huge

phosphoenolpyruvate has a ______ (huge/small) phosphoryl group transfer potential (-14.8 kcal/mol)

glyoxylate, acetyl CoA

plants use the ____ cycle to synthesize carbohydrates from ______. Low [AMP] (high energy charge) activates a kinase that _____ and inactivates isocitrate dehydrogenase, blocking the citric acid cycle and shunting into the glyoxylate cycle to store sugar.

dehydrogenase, E1, E3, NAD+

pyruvate ______ is the huge enzyme protein complex ("soccer ball"; similar to alpha-ketoglutarate dehydrogenase, but different E1/E2) btw glycolysis and the citric acid cycle. It has 60 E1, 60 E2, and 12 E3, with E2 having a swinging arm that picks up a substrate from ___ and moves it to _____. Regeneration of the oxidized (lys) swinging arm is thru reduction ____

endproduct, active, phosphorylation, E2, E1

pyruvate dehydrogenase regulation: 1) ________ inhibition at the ____ site (non-allosteric) 2) ______ via NADH and acetyl CoA activating a kinase that inactivates the enzyme. The kinase and phosphatase are bound to ____ core and act on specific Ser residue of ____ (active vs inactive dependent on balance of phosphatase vs kinase rxn)

acetyl, co2, NADH

pyruvate dehydrogenase rxn produces _______ CoA + ____ (gas) + _____

energy charge, ATP, energy charge, low, low

regulating glycolysis: This can occur via cellular __________. Flux increases when [____] is needed. In cell, [ATP] varies very little, but [AMP] and [ADP] can vary a lot and indicate ______. Low ATP means _____ energy charge. High ADP/AMP mean ______ energy charge

electron transport chain (aka respiratory chain)

rxns carried out by complexes I-IV of ox phosphorylation in which electrons from NADH and succinate pass thru a series of electron carriers to ultimately reduce O2 to H2O, with the free energy released by these oxidation/reduction rxns used to pump protons out of the mitochondrial matrix

cytochromes

small proteins found in electron transport complexes, or existing as a separate protein (e.g. in the case of cytochrome c) that carry a heme group. They can carry on electron by reducing the iron ion at the center of the heme, and can then give up the electron when the iron is reoxidized

delta G = std delta G + RTlog([B]/[A])

std delta G and actual delta G equation

gluconeogenesis, lactate, fermentation, glucose

the Cori cycle allows muscles in an animal to carry out a sprint for longer. ______ in the liver recycles the ______ from anaerobic homolactic _______ in the muscle back to ______ that is then returned to the muscle

Cori

the _____ cycle allows muscles in an animal to carry out a sprint for longer. Gluconeogenesis in the liver recycles the lactate from anaerobic homolactic fermentation in the muscle back to glucose that is then returned to the muscle

chemiosmotic

the ______ hypothesis is that energy released by electron transport is stored in a proton gradient across the inner mitochondrial membrane, and is then used to make ATP

binding change

the ________ model explains how ATP synthase uses energy from the mitochondrial proton gradient to synthesize phosphoanhydride bonds to make ATP

gluconeogenesis

the anabolic pathway that generate glucose from pyruvate

phosphoanhydride bond

the chemical bond between two adjacent phosphate groups. ATP has two of these bonds. These bonds have a relatively high standard free energy of hydrolysis (~7.3 kcal/mol)

homeostasis

the concept that living organisms tend to maintain themselves in a constant state. As applied to metabolism, the term is used to mean that metabolites tend to be maintained at a constant concentration despite large changes in metabolic flux

ATP, o2, glucose

the cori cycle allows muscle to continue making ____ as _____ (gas) and _____ run low

group transfer potential

the energy released when a bond to a chemical group is hydrolyzed. A chemical group can be transferred from a molecule that has a higher potential to one with a lower potential to give a reaction negative standard delta G

electron transfer potential

the energy released when a molecule is oxidized (i.e. transfers electrons to another molecule)

reciprocal, 0, regulated

the enzyme for an equil rxn is often used in both a catabolic pathway and its ______ anabolic pathway (catalyzes rxn in both directions). At non-equil steps, these pathways must use diff enzymes that cat rxns not exactly opposite of each other so that 1) delta G <= _____ in each direction AND 2) the enzymes can be reciprocally _______

first committed step

the first non-equilibrium reaction unique to a metabolic pathway. Usually used as the control point to regulate flux through the pathway.

proton motive force, 3

the force pushing protons down (0.224 V) their electrochemical gradient. _____ H+ transported drives 1 ATP synthesis

glucose, gluconeogenesis

the human brain runs almost entirely on energy from blood _____, which is why _______ in the liver is imp

coordinately, intermediates, share

the non-equil rxns of a metabolic pathway are ______ regulated to alter flux thru the pathway while keeping the ______ at approx constant conc. This allows large changes in flux of the pathway without affected flux thru any other pathways that _____ the same intermediates

citric acid cycle

the pathway that oxidizes the acetyl group of acetyl CoA to 2 CO2, conserving the liberated free energy for ATP production. This pathway oxidizes breakdown products of glucose, fats, and aa's. Intermediates are also a source for many biosynthetic pathways

ox phosphorylation

the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 via a series of electron carriers. Two components of the process are electron transport (which pumps protons across the membrane) and ATP synthesis (which is driven by energy stored in the proton gradient)

substrate-level phosphorylation

the process in which enzymes directly transfer phosphoryl groups from substrates with high phosphoryl group transfer potential to ADP to generate ATP

flux

the rate (amt metabolites per unit time) at which metabolites flow thru a pathway. This rate thru glycolysis varies by >100-fold in muscle depending on ATP need