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Biochem Exam III

Terms in this set (293)

The TCA cycle is a series of organic reactions that oxidizes an acetyl group to ___ CO2 molecules producing ___ NADHs, __ FADH2, and __ GTP.
2; 3; 1; 1
This means to operate in both catabolic and anabolic modes (make or break molecules)
amphibolic
Pyruvate is similar to which amino acid?
alanine
Alpha-ketoglutarate is similar to which amino acid?
glutamate
Oxaloacetate is similar to which amino acid?
aspartate
FADH converts an alkane to an ____.
alkene
NADH oxidizes alcohols to ____.
ketones
The two carbons that you react with to make citrate in the TCA cycle shows that the CO2's that come off in the cycle ARE or AREN'T from acetyl-CoA.
aren't
When you convert oxaloacetate to citrate, what is the key intermediate?
acetyl-CoA enolate
Does the acetyl-CoA that enters the TCA cycle immediately get oxidized to CO2?
no (it reacts with oxaloacetate to make a 6 carbon citrate. the co2 that comes from acetyl CoA actually gets recycled)
How many ATPs are made in one turn of the TCA cycle?
1
Is oxaloacetate used up in the TCA cycle?
no (good for gluconeogenesis, keeps the cycle going, and helps with biosynthesis)
Is the oxaloacetate that is regenerated after one turn of the cycle, the same one that went in?
no (lost two molecules of carbon dioxide and had many reactions take place, so the carbons aren't the original carbons)
Is a thiol ester HIGH or LOW energy?
high
Is citryl-CoA high energy?
yes (it's a thiol ester)
How many carbons does oxaloacetate have?
4
How many carbons does citrate have?
6
What is the kind of reaction between an enol and condensed with a carbonyl?
ester-aldol condensation
Is Citrate chiral or prochiral?
prochiral
What is the name of the enzyme that converts oxaloacetate to citrate?
citrate synthase
Iron sulfur centers are generally used for ____ transport.
electron
With converting citrate to isocitrate, what is the overall transformation that takes place?
isomerization
What is the enzyme used to convert citrate to isocitrate?
aconitase
Is isocitrate chiral?
yes (has 2 chiral centers)
The iron-sulfur cluster behaves as a ___ acid with citrate and helps dehydrate ____ to cis-Aconitate intermediate. It then mediates the addition of the ____ in the other direction to get isocitrate.
lewis; citrate; water
How many carbons does isocitrate have?
6
NAD+ function in the isocitrate to alpha-ketoglutarate reaction is to oxidize the SECONDARY or TERTIARY alcohol to a ketone?
secondary
What is the name of the enzyme that converts isocitrate to alpha-ketoglutarate?
isocitrate dehydrogenase
The Mn in the isocitrate dehydrogenase reaction facilitates decarboxylation of the _____ acid - acts as a lewis acid.
beta-keto
Alpha-keto acid needs coenzyme ____ to decarboxylate while beta-keto acids decarboxylate spontaneously.
TPP
What is the key intermediate of the isocitrate dehydrogenase reaction?
oxalosuccinate
How many carbons does alpha-ketoglutarate have?
5
With the isocitrate dehydrogenase reaction, the two isoforms of oxalosuccinate both catalyze the same reaction, but one participates in the ___ ___, is located in the mitochondria, and uses NAD+ as a cofactor. The other occurs in the mitochondria and the ___, utilizes NADP+ as a cofactor and generates NADPH for reductive biosynthesis.
TCA cycle; cytosol
Is a CO2 released in the isocitrate dehydrogenase reaction? Is NADH?
yes (1 of each)
In the reaction of alpha-ketoglutrate to succinyl CoA reaction, NAD+ is involved to reoxidize ____.
FADH2
What is the enzyme that converts alpha-ketoglutarate to succinyl CoA?
alpha-ketoglutarate dehydrogenase
How many CO2 are produced in the alpha-ketoglutarate dehydrogenase reaction?
2
How many NADH are produced in the alpha-ketoglutarate dehydrogenase reaction?
1
Is succinyl CoA a thiol ester or a mixed anhydride?
thiol ester
The alpha-ketoglutarate to succinyl CoA reaction is similar to which reaction in glycolysis?
pyruvate dehydrogenase (identical meachanism to PDC)
Succinyl phosphate is a high energy mixed anhydride made from ___ acid and ___ acid.
phosphoric; succinic
What is the name of the enzyme that converts succinyl CoA to succinate?
succinyl CoA synthetase
How many carbons does succinate have?
4
Does the succinyl CoA synthetase reaction produce 1 GTP?
yes
In the succinyl CoA synthetase reaction, phosphohistidine is regenerated by ___ ____.
succinyl phosphate
What is the free energy change of succinyl CoA to succinyl phosphate?
zero
What is the free energy change of succinyl phosphate to 3-Phospho-His?
zero
What is the free energy change of 3-Phospho-His to GTP?
zero
What is the business end of FAD that gets reduced if an alkane gets oxidized? It's a prosthetic group, a heterocycle, and it's a good electron sink.
flavin
What is the name of the enzyme that converts succinate to fumarate?
succinate dehydrogenase
Is succinyl dehydrogenase part of the mitochondrial inner membrane?
yes
Can malonate inhibit the reaction of succinate dehydrogenase?
yes
How many FADH2 are made in the succinate dehydrogenase reaction?
1
Having succinate dehydrogenase being part of the mitochondrial inner membrane allows the funneling of electrons directly in the ____. It takes the electrons from succinate via ____.
ETC; FAD
Is malate chiral?
yes
What is the type of reaction catalyzed by fumarase?
hydration
What is the name of the enzyme that converts fumarate to malate?
fumarase
Hydrotase step of ___ ___ of lipids is similar to the fumarase reaction.
beta oxidation
The TCA cycle operates when the malate/oxaloacetate equilibrium lies mostly on the side of malate because the energy of the hydrolysis of the ___ ___ bond formed in the next reaction drives this reaction forward.
thiol ester
What is the enzyme that converts Malate to Oxaloacetate?
malate dehydrogenase
After the malate dehydrogenase reaction occurs, how many NADs have been used in the TCA cycle?
3
In aerobic conditions, we can create ___ ATP per glucose when considering glycolysis, PDC, and the TCA cycle.
38
How many ATP molecules are made per NADH in the ETC?
3
How many ATP molecules are made per FADH2 in the ETC?
2
The decarboxylation of pyruvate by PDC is ____, thus regulated.
irreversible
NADH and ____ are competitive inhibitors of pyruvate dehydrogenase.
acetyl-CoA
Pyruvate dehydrogenase makes the ___ ___ so it's a primer regulating step in PDC.
acetyl-CoA
In covalent modification, is the active form of an enzyme always the dephosphorylated form?
no (the phosphorylation state isn't tied to active or inactive)
NADH and acetyl CoA activates the kinases in PDC because the energy charge is ___.
high
Which hormone reverses inactivation of pyruvate dehydrogenase kinase by activating the phosphatase?
insulin
Citrate synthase in the TCA cycle can be inhibited by ____ and ____.
Citrate; ATP
Isocitrate dehydrogenase can be inhibited by ___ energy charge and high [NADH/NAD+]. In this case ___ accumulates, leaves mitochondrion, and acts as an allosteric effector in glycolysis, gluconeogenesis, and fatty acid biosynthesis.
high; citrate
alpha-Ketoglutarate dehydrogenase is inhibited by high energy charge, NADH, and ____.
succinyl CoA
Per glucose molecule, how many NADH are made?
10
Per glucose molecule, how many FADH2 are made?
2
The ETC is located in the inner ____ membrane.
mitochondrial
In the ETC, electrons are passed along through sequential redox centers in 4 enzyme complexes ultimately reducing 02 to H20. During this process, ___ are expelled from the mitochondrion, producing a gradient across the membrane. Therefore the inside will get more negatively charged (more ___) and the outside will be positively charged (more ___).
protons; basic; acidic
The free energy of the electrochemical gradient in the ETC drives the ___ of ATP.
synthesis
Glycolytically produced NADH must gain access to ETC for aerobic ____. - neither NAD+ or NADH is transported across the inner membrane of the mitochondrion.
oxidation
Mitochondrially produced ATP needs to get to the ___ where most ATP-utilizing reactions take place.
cytosol
With the ATP-ADP translocater in innner membrane of the mitochondria, the ___ gradient drives ATP leaving the mitochondrion and ADP entering.
electrostatic
The phosphate ____ is a symporter where H2PO4 (inorganic phosphate) and a proton go into the matrix of the mitochondrion.
translocase
The malate-aspartate shuttle is reversible and driven by concentration gradients. It's the most active shuttle, occurs in the kidney, ___, and heart mitochondria.
liver
In the Malate-Aspartate shuttle, oxaloacetate is converted to malate using NADH and ___ ____. Then the malate uses the malate alpha-ketoglutarate transporter to go into the matrix only to be broken back down into oxaloacetate using ___ and malate dehydrogenase. The oxaloacetate is then converted into ___ with aspartate aminotransferase. (It does this by taking an amino group from glutamate and sticking it onto oxaloacetate). The glutamate molecule gets converted to alpha-ketoglutarate which gets pumped out so malate can come in while the aspartate leaves the matrix through the __-___ transporter.
malate dehydrogenase; NAD+; aspartate; glutamate-aspartate
This complex passes electrons from NADH to CoQ.
complex 1
This complex passes electrons from reduced CoQ to cytochrome C.
complex 3
This complex is the terminal enzyme of the ETC and it catalyzes the one-electron oxidations of 4 consecutively reduced cytochrome C molecules and the concomitant four-electron reduction of one O2 molecule to yield H20.
complex 4
The TCA cycle interacts with the ETC at complex __.
2
The flow of electrons of the ETC is from 1 to 3 to ? OR it is from 2 to 3 to 4, but 1 doesn't interact with 2.
4
Which complexes in the ETC pump out protons?
1, 3, and 4.
Does complex 2 of the ETC have enough thermodynamic power to make ATP on its own?
no
The respiratory complexes of the ETC exist in the inner membrane because a ___ is set up and they need to directly interact with matrix components.
gradient
Does the proton gradient drive ATP synthesis?
yes
The ___ membrane of the mitochondrion is exposed to the cytosol
inner
Is the intermembrane space exposed to the cytosol?
yes
In which subunit is ATP made?
alpha3-beta3
Does F1 synthesize ATP?
yes
Conformation changes of the alpha3-beta3 protomer is the role of the ?
rotary
The proton gradient entering through __ subunit and F_ fragment drives the rotary action.
c; 0
This is a disconnection of electron transport through complex 1, 3, and 4 and oxygen reduction.
uncoupling
This molecule uncouples ATP synthesis (oxidative phosphorylation) from the ETC. It works by upsetting the proton gradient - shuttles protons into the intermembrane space. It can uncouple complex V from the ETC.
DNP (2,4-Dinitrophenol)
Having DNP shuttle protons into the intermembrane space upsets the proton gradient. The ETC would still be running and the energy couldn't be used to make a proton gradient, so ____ would be generated because the energy has no place to go.
heat
When complex V is inhibited by _____, nothing happens to the ETC but there's no ATP synthesis.
oligomycin
When complex I is inhibited by ____, the electron transport rate is reduced because you only have complexes 3 and 4 pumping electrons.
rotenone
Glycogen functions to _____ glucose for later metabolic use.
stockpile
Constant supply of glucose is needed for _____ and ______ because other tissues can use fatty acids for energy and these cannot.
brain; red blood cells
Glucose is the only _____ under non-starving conditions that the brain and red blood cells can use.
fuel
The _____ and muscles have glycogen stores.
liver
The _______ keep glycogen for themselves while the liver supplies it to the rest of the body.
muscles
Mobilization of glucose to ______ (primarily in liver) affords a constant supply of glucose (~5 mM in blood) to all tissues.
glycogen
____% of the liver's weight is glycogen.
8
Muscle mass has around less than ____% of glycogen.
1
Is there more glycogen in the muscles or liver?
muscles
_____ levels spike after you eat a meal.
insulin
This promotes all glucose utilization pathways.
insulin
_____ levels are high before a meal because it stimulates the body to make glucose from non-carbohydrate starting materials.
Glycogen
The liver's capacity to store glycogen is sufficient to supply the brain with glucose for ____ hrs.
12
Under fasting conditions, most of the body's needs for glucose are met by _________.
gluconeogenesis
90% of glycogen is made directly into ?
glucose-6-phosphate
This pathway makes riboses and is a source for NADPH.
pentose phosphate pathway
Glycogen synthesis/degradation and gluconeogenesis/glycolysis are _________ regulated.
reciprocally
Alpha 1-4 linked polymer of glucose describes what?
glycogen
Glycogen _______ contain enzymes that catalyze glycogen synthesis and degredation (and enzymes which regulate these processes)
granules
Glucose units are mobilized by sequential ______ from the glucan chain's non-reducing ends
removal
Glycogens' highly branched structure is optimized for ________ release of glucose units from every branch point.
simultaneous
Muscles CAN or CANNOT mobilize fat as rapidly as they can glycogen?
cannot
The fatty acid residues of fat CAN or CANNOT be metabolized anaerobicallly?
cannot
Animals CAN or CANNOT convert fatty acids to glucose.
cannot
In the muscle, the need for ATP results in the conversion of glycogen to ______ for entry into glycolysis.
glucose-6-phosphate
In the liver, _____ blood glucose triggers glycogen breakdown to glucose-6-phosphate, which is hydrolyzed to glucose and released into the bloodstream.
low
Glycogen phosphorylase, glycogen debranching enzyme, and phosphoglucomutase are enzymes that are required for glycogen ______.
breakdown
This enzyme catalzyes glucogen phosphorolysis to give glucose-1-phosphate and glycogen minus one glucose (only releases glucose if more than 5 units from a branch).
glycogen phosphorylase
This enzyme removes glycogen's branches (makes additional glucose residues accessible to phosphorylase)
glycogen debranching enzyme
This enzyme converts glucose-1-phosphate to glucose-6-phosphate.
phosphoglucomutase
This is a phosphorylase cofactor that is covalently linked to the enzyme as a Schiff base (imine). It's primary use is transamination reactions.
PLP (Pyridoxal-5-phosphate)
In the glycogen phosphorylase mechanism, what is the key intermediate?
oxonium ion
In the glycogen phosphorylase mechanism, there IS or ISN'T retention of configuration overall? (this means the same sterochemistry or not?)
is
Glycogen debranching enzyme acts as an alpha 1-4 transglycosylase by transferring a 3-4 residue unit from the ____ branch to the non-reducing end of another branch.
limit
Phosphorolysis proceeds along glycogen branch until it gets within 4-5 residues of an alpha 1-6 branch - leaving a _____ branch
limit
Glycogen debranching enzyme has two activities: hydrolyase and transferase. It takes the ___ branch, all but the last unit, and transports that branch onto the longer strand. The last unit, ___, is hydrolyzed to form free glucose.
limit; glycosyl
What key amino acid is found with phosphoglucomutase?
serine
UDP-glucose pyrophosphorylase, Glycogen synthase, and glycogen branching enzyme are all a part of glycogen _______.
synthesis
This enzyme catalyzes the reaction of UTP and glucose-1-phosphate to form UDP-glucose.
UDP-glucose pyrophosphorylase
The ______ oxygen of glucose-1-phosphate attacks phosphorous atom of UTP to form UDPG.
phosphoryl
The inorganic pyrophosphate that forms with UTP + G1P = UDPG is a highly ______ reaction.
exergonic
In the glycogen _____ reaction, the glucose unit of UDPG is transferred to the C4-OH group on one of glycogen's nonreducing ends.
synthase
The delta G is ______ in glycogen synthase, making this reaction SPONTANEOUS or NON-SPONTANEOUS?
negative; spontaneous
UTP is replenished by nucleoside ______ _______.
phosphate kinase
Are UTP and ATP energy equivalent?
yes
Glycogen branching is accomplished by what?
amylo-(1,4-1,6)-transglycosylase
Glycogen branches are created by transfer of terminal chain segments consisting of _____ glucosyl residues to the C6-OH groups.
7
Each transferred segment, when dealing with glycogen branching, must come from a chain of at least _____ residues and the new branch point must be at least ___ residues away from other branch points.
11; 4
This enzyme generates glucose in the liver.
glucose-6-phosphatase
Although glucose-6-phosphate is produced in the ______, G6Pase resides in the ____ membrane of cells.
cytosol; ER
These are inherited disorders affecting glycogen metabolism - produce glycogen that is abnormal in quantity or quality.
glycogen storage diseases
Glycogen storage diseases that affect the liver generally produce _______ and ________.
hepatomegaly; hypoglycemia
Glycogen storage diseases that affect the muscles cause ____ ____ and _______.
muscle cramps; weakness
There are _____ major glycogen storage disease known and many of them are inherited disorders.
12
This is type I glycogen storage disease that has an increase of intracellular G6P - large accumulation of glycogen in liver and kidney - hepatomegaly, hypoglycemia, failure to thrive.
von Gierke's disease
This is a type II glycogen storage disease that is the most devastating of them. There's a large build up of normal glycogen in lysosomes, causes death by cardiorespiratory failure usually by 1 year.
Pompe's disease
This type II glycogen storage disease is when glycogen with very short outer chains accululate in the liver and muscle - results in hypoglycemia. A high protein diet can offset the loss of amino acids from gluconeogenesis.
Cori's disease
This type IV glycogen storage disease is one of the most severe glycogen storage diseases where people rarely survive past 4 years due to liver dysfunction. It's where liver glycogen has long unbranched chains - reduced solubility.
Andersen's disease
This type V glycogen storage disease where there's painful muscle cramps on exertion. It affects glycogen metabolism in the muscle but not the liver.
McArdle's disease
This type VI glycogen storage disease has symptoms similar to mild type I disease. Hypoglycemia in this case results from liver's inability to respond to need for circulating glucose.
Her's disease
This type of glycogen storage disease is the only disease with a deficiency rather than overabundance of glycogen. Activity of glycogen synthase is very low - get hyperglycemia after meals and hypo inbetween.
Type O
Both glycogen synthesis and breakdown are ______ under the same physiological conditions.
exergonic
Which form of glycogen phosphorylase is the active form?
a
Which form of glycogen phosphorylase is the less active form?
b
Which kinase is the most important for glycogen synthesis?
glycogen synthase kinase 3
This enzyme phosphorylates 3 serines on glycogen synthesis per subunit.
glycogen synthase kinase 3
This enzyme "activates" glycogen phosphorylase with the help of ATP.
Phosphoylase kinase b
Both GSK3 and PKB need to be _______ to be active.
phosphorylated
All regulated enzymes of glycogen metabolism become phosphorylated by the _____-induced phosphorylation cascade.
cAMP
Myocytes receive epinephrine and are coupled with G__ receptors. This activates ____ cyclase and increases levels of cAMP. cAMP then ______ PKA. PKA then activates _______ _ kinase and calcium levels increase. This then _______ glycogen phosphorylase a. This converts glucose to glucose __-phosphate. Therefore glycolysis occurs along with muscle _____.
s; adenylyl; activates; phoshporylase b; activates; 1; contraction
Glucagon binds to a receptor on the liver cells and [cAMP] INCREASES or DECREASES?
increases
This adrenergic receptor is linked with adenylate cyclase on muscle and liver cells.
beta
This adrenergic receptor is linked to increasing calcium levels in the liver cell.
alpha
Insulin is largely a ___-phosphorylator.
de
Insulin DOES or DOESN'T promote glycogen synthesis.
does
GLUT _ is in the liver and pancreatic cells and it's not insulin/hormone dependent. It's always on and it's bidirectional.
2
GLUT _ takes glucose in and goes purely for glycolysis.
4
Which adrenergic receptors are found on hepatocytes?
beta 2, beta 3, and alpha 1
Muscle cells, which have beta receptors respond to _____ by breaking down glycogen for glycolysis generating ATP and helping muscles cope.
epinephrine
Mostly _____ __ receptors are on the muscle.
beta 2
Epinephrine promotes the ____ of glycagon from the pancreas.
release
Epinephrine binds to beta receptors on the liver cells and promotes glycogen _____ and also binds to alpha receptors on hepatocytes that increase ____ levels.
breakdown; calcium
Insulin binds to it's receptor on the myocytes and hepatocytes and signals through the ____ cascade to stimulate glycogen synthesis.
PKB (protein kinase B)
Insulin stimulates glycogen synthesis by ____ levels of cAMP through activation of phosphodiesterase; ______ of glycogen synthase kinase 3; and stimulatin of ____ ____ _ which reverse cAMP-induced phosphorylations.
reducing; inhibition; protein phosphatase-1
Rates at which glycogen is synthesized by glycogen synthase and degraded by phosphorylase are controlled by levels of what allosteric controllers?
AMP, ATP, G6P, and glucose
AMP, ATP, G6P, and glucose control the _____/_____ of glycogen synthase and glycogen phosphorylase.
phosphorylation/dephosphorylation
The _____ and ____ which catalyze the phosphorylation/dephosphorylation of glycogen synthase and glycogen phosphorylase are part of amplifying cascades that are ultimately controlled by hormones glucagon, insulin, epinephrine, and by Ca levels.
kinases; phosphatases
Glycogen phosphorylase of liver is a glucose _____.
sensor
Beta cells in the pancreas are ____ metabolism centers - they sense the flux of glucose in the TCA cycle of the mitochondria
oxidative
Can lactate, pyruvate, and glycerol be converted to glucose?
yes
Gluconeogenesis occurs in the ____ and to a smaller extent, in the kidney.
liver
The only amino acids that cannot be converted to oxaloacetate in animals are ___ and ____ because their breakdown yields only acetyl CoA.
leucine; lysine
All precursors must be converted to ______, the starting material for gluconeogenesis.
oxaloacetate
Oxaloacetate is similar to what amino acid?
aspartate
Pyruvate is similar to what amino acid?
alanine
Alpha-ketoglutarate is similar to what amino acid?
glutamate
Which steps of glycolysis have to be bypassed because they are physiologically irreversible, so gluconeogenesis can occur?
hexokinase, PFK, and pyruvate kinase
This molecules is used anytime that you use a CO2 as a starting material.
Biotin
Which enzyme helps stick a CO2 back on pyruvate?
pyruvate carboxylase
Oxaloacetate uses _____ to add a phosphoryl group to make phosphoenolpyruvate.
PEPCK
Can muscles go through gluconeogenesis?
no
When pyruvate is converted into PEP (phosphoenolpyruvate), what is the high-energy intermediate?
oxaloacetate
____ _____ catalyzes the ATP driven formation of oxaloacetate.
pyruvate carboxylase
_____ _____ (PEPCK) converts oxaloacetate to PEP.
PEP carboxykinase
What is your source of carbon dioxide when pyruvate is converted to PEP?
bicarbonate
Pyruvate carboxylase DOES or DOESN'T have a biotin prosthetic group?
does
Biotin is covalently bound to enzyme by amide linkage - often called a _____ residue.
biocytin
Carboxyphosphate is a ___ _____, so it's a higher energy molecule. It CAN or CAN'T spontaneously decarboxylate in the presence of biotin.
mixed anhydride; can
What is the intermediate in phase I of the pyruvate carboxylase reaction?
carboxyphosphate
What are the key intermediates in phase II of the pyruvate carboxylase reaction?
aza-enolate and pyruvate enolate
In which phase of the pyruvate carboxylase reaction is where the activated carboxyl group of carboxybiotin is transferred to pyruvate in a 3-step reaction to form oxaloacetate?
phase II
Does phase I and phase II of the pyruvate carboxylase reaction occur on the same enzyme?
Yes (just different subsites)
What serves to transfer the biotin ring between phase I and phase II of the pyruvate carboxylase reaction?
arm of biocytin
PEPCK catalyzes GTP-driven decarboxylation of ______ to form PEP and GDP.
oxaloacetate
Oxaloacetate can be considered to be ______ pyruvate - CO2 and biotin facilitating the activation at the expense of ATP.
activated
Can oxaloacetate beta eliminate?
yes
Gluconeogensis requires metabolite transport between _____ and cytosol.
mitochondria
Formation of oxaloacetate from pyruvate or TCA cycle occurs only in the _____.
mitochondria
The enzymes that convert PEP to glucose are _______.
cytosolic
PEPCK is distributed equally between the ______ and ______.
mitochondria; cytosol
Is there a transport system for oxaloacetate?
No
Gluconeogenesis DOES or DOESN'T use the reverse of malate-asparate shuttle?
does
Since oxaloacetate doesn't have a transport system for itself, it must be converted into either ______ or ______ for transport.
aspartate; malate
The malate dehydrogenase route of oxaloacetate results in transport of reducing equivalents to ______.
cytosol
The aspartate aminotransferase route of oxaloacetate DOES or DOESN't involve NADH?
doesn't
Which route is usually operational for oxalacetate to leave the mitochondria during gluconeogenesis because cytoslic NADH is required?
malate dehydrogenase
We ______ glucose in the muscle in order to trap it in the muscle.
phosphorylate
_______ reactions bypass PFK and hexokinase.
hydrolytic
The hexokinase reaction is bypassed by the hydrolytic cleavage of the _______ phosphate ester, catalyzed by glucose-6-phosphatase.
glucose-6-phosphate
The irreversible PFK reaction is bypassed by ________ which catalyzes the hydrolysis of FBP carbon 1 phosphate.
fructose-1,6-bisphosphatase
PEP is processed to ______ through the reversible reactions of glycolysis.
fructose-1,6-bisphosphate
Net energy cost of converting 2 pyruvates to 1 glucose is __ ATP.
6
Energetic cost of futile cycle in which glucose is converted to pyruvate and then resynthesized is __ ATP.
4
Do the pathways of gluconeogenesis and glycolysis proceed simultaneously in vivo?
no
The flux through the substrate cycle created by the opposing actions of PFK and FBPase is determine by the concentration of _____.
fructose-2,6-bisphosphate
This molecule is an extremely potent allosteric activator of PFK and inhibitor of FBPase. It activates glycolysis if its levels are low and stops gluconeogenesis. If levels are high, the it deactivates glycolysis and activates gluconeogenesis.
fructose-2,6-bisphosphate
F6P dephosphorylates to F2,6P with the help of what?
ATP (and liver PFK-2)
F2,6P phosphorylates to F6P with the help of what?
water (and liver FBPase-2)
Balance of the interconversions of F6P and F2, 6P are under ______ control.
hormone
When [glucose] is low, glucogon stimulates cAMP in _____ cells.
liver
Increase cAMP in liver cells activates PKA to phosphorylate, the bifunction enzyme (Ser) which inactivates ____-activity and activates _____ activity.
PFK-2; FBPase-2
When PFK-2 activity decreases and FBPase -2 activity increases, the net result is a decrease in F2, 6P concentration, shifting the balance between PFK and FBPase activity in favor of _____ hydrolysis. Therefore Gluconeogenic flux is increased.
FBP
Pyruvate kinase is allosterically inhibited in the liver by _____, a major gluconeogenic precursor.
alanine
Liver pyruvate kinase is inhibited by alanine and by _______.
phosphorylation
Since phosphorylation activates glycogen phosphorylase, glycogen break down and gluconeogenesis both flow toward ____, which is converted to glucose for export from the liver.
glucose-6-phosphate
_____ and adrenal hormones influce rates of transcription and stabilities of mRNAs encoding many regulatory proteins of glucose metabolism.
pancreatic
Insulin _____ the transcription of the gene for PEPCK.
inhibits
_____ [cAMP] promotes the transcription of genes for PEPCK, FBPase, and G6P, and represses transcription of genes for glucokinase, PFK, and the PFK-2/FBPase-2 bifunctional enzyme.
high
Glycerol enters gluconeogenesis at the level of the _____ phosphates.
triose
Acetyl CoA CAN or CANNOT be converted to glucose?
cannot
Gluconeogenesis primarily depends on what?
amino acids
What glycolytic enzyme is similar to phosphoglucomutase?
phosphoglycerate mutase
When phosphoglucomutase interconverts G1P and G6P, it goes through the _____ intermediate to regenerate the enzyme.
bisphosphate
What is the key metabolite for glycogen synthesis and glycogenolysis?
glucose 1 phosphate
What is the regulated enzyme of glucogen breakdown?
glycogen phosphorylase
What is the regulated enzyme of glycogen synthesis?
glycogen synthase
What is an allosteric activator of glycogen synthase-b?
glucose 6 phosphate (binds the enzyme and converts it to a conformation that stabilizes the inactive form)
Glucose 6 phosphate ____ glycogen phosphorylase.
inactivates
Kinases effect phosphorylation of glycogen synthase and glycogen. ____ for synthase a that turns it off and ___ ___ _ for phosphoylase b that turns it on.
GSK3; phosphorylase kinase b
These ultimately control the phosphorylation state of glycogen synthase and glycogen phosphorylase.
hormone
Does ATP INACTIVATE or ACTIVATE glycogen phosphorylase b?
inactivate
A high concentration of glucose makes it an allosteric ____ of glycogen phosphorylase a.
inactivator
Insulin activates ___, which takes the phosphate groups off to counteract the actions of phosphorylase kinase b.
phosphorylase a
This molecule activates PFK1 and inhibits FBPase gluconeogenesis. It's role is to activate glycolysis and inactivate gluconeogenesis.
fructose-2,6-bisphosphate
Are there glucagon receptors on muscles cells?
no
This enzyme degrades triacylglycerides to free fatty acid and monoacylglyceride so they can get through the intestinal mucosa.
intestinal lipase
This enzyme degrades triacylglycerides to free fatty acid and monoacylglyceride to go through the capillaries that feed the adipocytes.
lipoprotein lipase
These enzymes mobilize fat in the form of free fatty acids in the times of energetic needs.
hormone sensitive lipase
This surrounds fat droplets in adipose tissue to keep them intact and from being mobilized too soon.
perilipin
When perilipin is phosphorylated, it allows access to ___ ___ ___ to chip off the fatty acid.
hormone sensitive lipase
In the ____ state, through cAMP and PKA, hormone sensitive lipase is most active.
phosphorylated
This hormone induces dephosphorylation of hormone sensitive lipase and signals that there's plenty of fuel.
insulin
Fatty acids are activated by attachment to ____.
CoA
When fatty acids are activated by CoA (acyl CoA synthetase), what is the key intermediate?
Acyladenylate mixed anhydride
Once the fatty acid attacks ATP, PPi is released. This drives the reaction because it is highly ___ and ___.
exergonis; irreversible
This enzyme catalyzes the reaction of fatty acid to fatty acyl-CoA.
acyl coA synthetase
There are 3 different acyl CoA synthetases because their chain ___ of fatty acids differ.
length
This shuttle allows fatty acyl CoA to get into the mitochondria for beta oxidation.
carnitine shuttle
At what point does the acyl CoA dehydrogenase interact with the ETC?
coenzyme Q
What reaction in the beta oxidation pathway of fatty acyl CoA is catalyzed by a hydratase?
second reaction
With the four steps of the beta-oxidation pathway of fatty acyl CoA, the first step is an oxidation of fatty acyl CoA to trans Enoyl CoA (an alkane to ___). The second step is a hydration of trans Enoyl CoA to 3-L-Hydroxyacyl-CoA (forms the hydroxyl on the __ position). The third step is an oxidation of 3-L-Hydroxyacyl-CoA to beta-Ketoacyl-CoA (gives a ketone). The fourth step is a cleavage of beta-ketoacyl-CoA into fatty acyl-CoA and ____.
alkene; beta; acetyl CoA
Water soluble fatty acids that can get into the brain are called ?
ketone bodies
Ketone bodies are important during times of ____ because they give food to the brain.
fasting
HMG-CoA is used in Ketogenesis as well as ___ synthesis.
cholesterol
____ in the cell influence the relative amount of acetoacetate and D-beta-hydroxybutryate in the cell?
NADH
Because the 3-keto-CoA transferase is already high energy (due to borrowing succinyl CoA from TCA cycle), when they break the ketone bodies back down they don't require the use of ___.
ATP
In the conversion of ketone bodies to acetyl CoA, the thiolase reaction is a retro-claisen and makes __ acetyl CoA.
2
Can the liver produce ketone bodies?
yes
Can the liver use ketone bodies?
no (it doesn't have the enzyme, 3-ketoacyl CoA transferase, to process them)
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