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54 Cards in this Set
- Front
- Back
stage 1 - 2nd step
isomeration of glucose 6 phosphate to? (changing from an aldose to?) this step is catalyzed by? |
fructose 6 phosphate
ketose phosphoglucose isomerase |
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why bother ismerizing g6p to f6p?
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glucose does not break down into a three carbon as easily as fructose
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stage 1 - 3rd step
----- of f6p to form ? catalyzed by? this is the --- step |
phosphorylation, f16bp
pfk (phosphofructokinase) commited |
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PFK is a key ------- ------- enzyme
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regulatory allosteric
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Splitting stage
what cleaves f16bp? what are the two molecules that result? is this process reversible or irreversible? |
aldolase
DHAP - dihydroxy acetone GAP - glyceraldehyde 3 phosphate reversiblec |
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conversion of DHAP to GAP is -----
achieved through what ensyme? |
reversible
triose phosphate isomerase |
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Stage 2 - Energy Capture Reaction 1
GAPDH creates ---- and ----- this is ----- and requires ----+ |
NADH, 1,3-BPG
reversibe, NAD+ |
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when GAP is turned into 1,3-BPG by GAPDH... there is a ----- intermediate which is more/less stable than the reactants and hence, its formation is spontaneous or nonspontaneous?
the thioester intermediate is less/more stable than the product, which forms ------ there is a coupling of two reaction with GAPDH in which it lowers a large activation barrier (page 258) |
thioester, more, spontaneously
less, spontaneously |
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Energy Capture 2 - Atp
what converts ADP to ATP using phosphate from ? this is ---- level phosphorylation all invest atp is ----- rxn is rev or irrev 1,3-BPG is transformed to 3-phosphoglycerate by ------ ----- to generate ----- |
phosphoglycerate kinase, 1,3-BPG
substrate recovered reversible phosphoglycerate kinase, ATP |
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Preparing for another energy capture
------- ------- rearranges a phosphoryl group from 3-phosphoglyceratte to --------- as a preparatory step this run is freely rev or irrev? |
phosphoglycerate mutase
2-phosphoglycerate freely reversible |
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------ converts 2 phosphoglycerate to ------- via a ---- rxn
the energy of hydrolysis change is ----- kcal/mol for 2-phosphoglycerate and ---- for PEP PEP has a high ------ transfer potential |
ENOLASE, PEP (phosphoenolpyruvate), dehydration
-4.2 -14.8 phosphoryl |
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Second energy capture
--------- converts PEP to ----- this captures ----- this rxn is rev or irrev? |
pyruvate kinase, pyruvate (TCA)
ATP irreversible under cell conditions |
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Glycolysis net reaction?
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glucose + 2 Pi + 2 ADP + 2 NAD+ -->
2 pyruvate +2 ATP + 2 NADH + 2H + 2 H2o |
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Under ----- conditions, ---- is shuttle into the ------
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aerobic, NADH, mito
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What three things can pyruvate be turned into?
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to ACETALDEHYDE which then turns to ETHANOL
LACTATE ACETYL CoA - this can further undergo oxidation |
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Regeneration of NAD+ is need for glycolysis to proceed
------ reaction produces NADH under anearobic conditions ---- production is proceeded to produce NAD+ under aerobic conditions the ---- ---- ---- is utilized to make NAD+ |
GAPDH
lactate electron transport chain |
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Pyruvate destination
1) Ethanol fermentation done only by ---- and other microorganisms pyruvate is first turned into ----- by ------. this enzymes requires vitamin ------ ----- is then turned into ----- by ------. this uses NADH and regenerates ----` |
yeast,
acetaldehyde, pyruvate decarboxylate thiamin/B1 acetaldehyde, ethanol, alcohol dehydrogenase, NAD+ |
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Lactic acid fermentation is the reduction of ----- to ----
this regenerates ------ the enzyme used is ------ |
pyruvate, lactate,
NAD+ lactate dehydrogenase |
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Lactic Acidosis is an emergency state- increase production of --- and decrease use of ----
lactate comes from anaerobic ----- standard blood lactate is approx --- mM acidosis levels at --- |
lactate, lactate,
glycolysis 1.2, 5 |
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other sugars such as ---- and ---- are metabolized into glycolysis intermediates
most ingested ---- is metabolized by the ---- |
fructose, galactose
fructose, liver |
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Fructose is turned into fructose 1 phosphate by ------
fructose 1 phosphate is then split into ---- and ---- ---- can then enter glycolysis this allows Glyceraldehyde to be phosphorylated by ----- kinase to form ------ Another way: fructose in the ----- tissue can be phosphorylated to ----- fructose in the ---- can be converted to -- and -- as well. |
fructokinase
glyceraldehyde, DHAP DHAP triose, glyceraldehyde 3-phosphate liver adipose, fructose 6 phosphate (F6P) liver,DHAP, GAP |
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Galactose can also be phosphorylated to ----- and then that intermediate can enter glycolysis
Step 1: Galactose is phosphorylate to ------ by ----kinase Step 2: Together with galactose 1-phosphate, replace glucose on UDP------ to become UDP-galactose which releases a ----- |
G6P
Galactose 1-phosphate, galactokinase UDP-glucose, glucose 1-phosphate |
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Step 3: UDP ----- is converted to UDP ----
Step 4: convert glucose 1-phosphate to ----------- by what enzyme? hint: enzyme has the word "mutase" |
galactose, glucose,
glucose 6-phosphate, phosphoglucomutaste |
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key concept:
enzymes catalyzing ------ reactions in metabolic pathways are points of ---- |
irreversible, reguation
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What are the regulated enzymes for glycolysis?
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hexokinase, phosphofructokinase (PK1),Pyruvate kinase
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Enzymes that are not regulatory often control "----- ----" rxns.
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near eqilibrium
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Regulation of glycolysis in the muscle
PFK - irreversible rxn , COMMITED STEP it is ----- regulated by ATP, ----- binding of ATP incr/decr affinity for F6P it is ---- regulated by AMP. it competes with ___ for the allosteric binding site it is ----- regulated by ---pH. need protection from excessive lactic acid fermentation reaction velocity is high/low with low levels of ATP. |
negatively, allosteric, decreases
positively, ATP negatively, low high |
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Hexokinase is inhibited by?
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Its own product: glucose 6-phosphate
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high concentration of glucose 6-phosphate indicate energy charge is ----
hexokinase also becomes inhibited by another regulatory enzyme: ---- |
high
PFK1 (phosphofructokinase) |
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IF PFK1 is inactive then it cannot convert F6P to ?
this leads to high levels of ---- which in turn raises levels of ----. Rising levels of ---- would thus inhibit hexokinase |
F 1,6-bisphosphate
F6P, G6P G6P |
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Regulation of glycolysis in muscle through pyruvate kinase
Pyruvate Kinase is negatively regulated by --- and --- Positively regulated by ? |
atp and alanine
fructose 1,6 bisphosphate |
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Regulation of glycolysis in liver
PFK is inhibited by ----- and activated by ----- through increasing PFK's affinity for --- |
citrate
F-2,6-BP (fructose 2,6 bisphosphate) -->(made from F6P, catalyzed by PFK to make F-1,6-BP) increas PFK affintiy for F -6P |
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The liver uses an isozyme of hexokinase called ------.
it has a much lower/higher affinity for glucose. (when glucose is low the liver does/doesn't use it, so it is preserved for the brain and other tissues) |
glucokinase, lower
doesn't |
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Glucokinase is/isnt inhibited by G6P
Glucokinase generates G6P for ---- and ----- synthesis |
isnt
glycogen, fatty acid synthesis |
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In the liver, pyruvate kinase is inhibited by -----
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phosphorylation
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When blood glucose level is high/low the phosphorylated pyruvate kinase is -------- by -----triggered protein phosphatase. The dephosphorylated pyruvate kinase is now more/less active and able to make ----.
When blood glucose level is low/high, the dephosphorylated pyruvate kinase is phosphorylated by --- and enters a less/more active form. |
high, dephos, insulin, more, pyruvate
low, ATP, less |
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PFK1 is the first/second commited step in glycolysis
What are the neg and pos allosteric regulators? |
first
NEGATIVE : low pH (in muscle), ATP, cirate (liver) POSITIVE : AMP, F 2,6 BP |
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AMP and ATP signal ---- state
pH signals info about the --- environment citrate signals the availability of --- ---- F 2,6-BP signals the ratio of ----/---- in the blood |
energy
internal alternative fuels insulin/glucose |
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Why is alanine an inhibitor of pyruvate kinase?
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Alanine is most commonly made by transfer of an amine group to pyruvate. Because transamination reactions are readily reversible, alanine can be easily formed from pyruvate and thus has close links to metabolic pathways such as glycolysis, gluconeogenesis, and the citric acid cycle.
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Tissue specific regulation - LIVER
The isozyme of hexokinase in liver is glucokinase or hecxokinase IV. it has a higher/lower km for glucose G 6-P is also used for ----- synthesis in liver through the ---- ---- pathway |
higher Km, because lower affinity
glycogen, pentose phosphate |
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continued...
is pfk negative regulation in liver significant? PFK is ----- by F 2,6BP in liver |
ATP and low pH regulation not as significant in liver
activated |
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Pyruvate kinase in liver is known as ---- ---- ----.
it is regulated by -------. Prevents liver from consuming glucose when blood-glucoes levels are low ----induced ---- pathway |
pyruvate kinase L
phosphorylation glucagon, cAMP |
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Glycolysis inhibition by -----
----- is a pancreatic hormone and activates ------. this raises/lowers blood glucose levels |
glucagon
glucagon,gluceogenesis, raises |
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Glucose transporters
Glut1? Glut3? Glut4? Glut2? |
Red Blood Cell 1
Brain 3 Muscle and Fat Cells 4 Liver and pancreatic beta cells 3 |
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Which glucose transporter(s) has a Km of ~1 mM, that is lower than blood glucose levels, AND continually uptake glucose?
Intermediate km? High km? which transporters are insulin dependent? |
Glut 1 and Glut 3 (rbc and brain)
glut 4 (muscle and fat cells) glut3 (liver and pancreatic beta cells) glut 4 and glut 3 are insulin dependent |
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insulin stimulates glucose uptake by adipos tissue and muscle by increasing the number of --- --- in the ---- ---.
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glucose transporters (GLUT4), plasma membrane.
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There is an overexpression of ---- enyzmes in cancer cells.
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glycolytic
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Cancer cells grow more rapidly than the blood vessels to nourish them; thus, as solid tumors grow, they are unable to obtain oxygen efficiently. In other words, they begin to experience -----, a deficiency of oxygen.
Under this condition, glycolysis leading to lactic acid fermentation becomes the primary source of -----. Glycolysis is made more efficient in hypoxic tumors by the action of a transcription factor, _____-______ _______ tractor. In the absence of oxygen, ----- increases the expression of most ----- enzymes and the glucose transporters ---- and -----. |
hypoxia
ATP hypoxia-inducible transcription factor (HIF-1) HIF-1, glycolytic, GLUT1, GLUT3 |
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Process of glycogen to glucose?
glucose to lactate? lactate to glucose? glucose to glycogen? |
glycogenolysis
glycolysis gluceoneogenesis gluconeogenesis glycogenesis |
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when oxygen is present how much atp per glucose molecule?
when oxygen isnt present? |
32 ATP
2 ATP |
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Stage 1 - priming of glucose
requires ---- ATP what is the end result? |
2
two 3-carbon fragments |
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stage 2 - harvesting ATP
oxidation of what? and substrate level ----. |
3 carbon fragment
phosphorylation |
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Stage 1 - 1st step
glucose is converted to --- by ---- this rxn is rev or irrev? |
G3P - glucose 3 phosphate
hexokinase irrev |
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Hexokinase phosphorylation of glucose ---- it inside the cell. it is no longer a ---- for the membrane glucose transporters
when glucose binds hexokinase via an ----- fit, it causes a ------ change in hexokinase. ----- then surround the glucose molecule, expelling --- for the environment --- then binds for ------- group transfer the removal of water from the active site protects --- from being hydrolyzed by the water |
traps, ligand
induced, conformational hydrophobic groups, h2o atp, phosphoryl ATP |