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BIO-430 Exam 3
| Question | Answer |
|---|---|
| key cofactor for alcohol dehydrogenase | Zn+2 |
| key residue for G3P dehydrogenase | Cys |
| key cofactor for pyruvate decarboxylase | TPP, Mg+2 |
| role of TPP | decarboxylation of a-keto acids, acts as an electron sink |
| pyruvate is the terminal e- acceptor in _____________ | lactic acid fermentation |
| how does TPP act as an e- sink? | thiazolium ring stabilizes carbanion intermediates by providing electrophilic structure into which the carbanion e- can be delocalized by resonance |
| ethanol is the ______ product in __________ | reduced, ethanol fermentation |
| functions of lipids (9) | -storage of energy, -insulation from environment, water repellant, buoyancy control and acoustics in marine mammals, membrane structure, |
| lipids that do not contain FA | isoprenoids |
| lipids that contain FA | complex lipids |
| as chain length increases, solubility ____ and melting point _____ | decreases, increases |
| FA are usually found as _____ | esters |
| majority of FA is found as ____ | triacylglycerols (TAGs) |
| solid TAGs are ______, liquid TAGs are _______ | fats, oils |
| advantages of fats over polysaccharides | -more energy/carbon because more reduced, carry less water because nonpolar |
| glucose and glycogen are for ________ needs | short-term |
| fats are for _______ needs | long-term |
| esters of long-chain FA with long chain alcohols | waxes |
| three categories of membrane lipids | phospholipids, glycolipids, archaebacterial ether lipids |
| the primary constituent of cell membranes | glycerophospholipids |
| phosphatidylcholine is _____________ of most eukaryotic cell membranes | the major component |
| plasmalogen is a __________ analog of phosphatidylethanolamine that is common in vertebrae _________, as well as protozoa and anaerobic bacteria | vinyl ether, heart tissue |
| platelet-activating factor is an ___________ analog of phosphatidylcholine in which acetic acid has __________ position C2 | alipathic ether, esterified |
| second most abundant type of phospholipid | sphingolipids |
| backbone of sphingolipids | long-chain amino alcohol sphingosine |
| sphingomyelin is __________ to phosphatidylcholine | structurally similar |
| sterols have a common core structure of _________ | four fused rings: three with 6C, one with 5C |
| structural role of sterols | - modulate fluidity and permeability of the membrane, thicken regions of the plasma membrane |
| mammals obtain cholesterol from _____ and ______ in the liver | food, synthesize |
| lipoproteins | biochemical assemblies containing both proteins and lipids, transport water-insoluble lipids in the bloodstream |
| steroid are ____________ of sterols and are more ________ than cholesterol | oxidized derivatives, polar |
| steroids are synthesized in which glands? | gonads and adrenal glands, from cholesterol |
| vitamin D3 | regulates metabolism of Ca+2 |
| Vitamin A | eyesight and healthy skin |
| Vitamin E | antioxidant |
| vitamin K | blood clotting cofactor |
| prostaglandins | inflammation and fever, smooth muscle contraction in uterus |
| thromboxane | formation of blood clots |
| leukotrienes | smooth muscle contraction in lungs |
| NSAIDS block _______ and _______ | prostaglandins and thromboxane |
| catabolism results in products that are _____ and is accompanied by the release of _______ | oxidized, free energy |
| ways reaction pathways can be regulated | - compartmentalized, allosterically, hormonally, genetically |
| hydrolysis reactions tend to be ___________ | strongly favorable (spontaneous) |
| isomerization tends to be ___________ | readily reversible |
| oxidation is often __________ | strongly favorable |
| coupled reactions allow for ______ | unfavorable reactions to be driven by a favorable reaction |
| favorable reactions _____ the concentration of reactants or ________ products, thus driving the reaction in the ________ direction | increase, decrease, forward |
| the flow of ________ can do biological _______ | electrons, work (reduced to oxidized) |
| NAD+ is a strong ________ | oxidizing agent ( C-OH to C=O, becomes NADH) |
| NADH is a strong ________ | reducing agent ( C=O to C-OH, becomes NAD+ and H+) |
| hydrolysis of ATP is favorable because of: | - better charge separation, increased resonance stabilization, immediate ionization of the product, better solvation of products |
| acteyl-CoA is an important _____ of _____ groups | donor, acyl |
| hydrolysis of thioesters is highly _______ | favorable |
| acetyl-CoA feeds _______ units into __________ pathways | two-carbon, metabolic |
| four major pathways of glucose utilization | storage, glycolysis, pentose phosphate pathway, synthesis of structural polysaccharides |
| net reaction of glycolysis | glucose + 2ADP + 2Pi + 2NAD+ -> |
| 2 pyruvate + 2 ATP + 2 NADH + 2H+ + 2 H2O | strongly favorable |
| net reaction of gluconeogenesis | 2 pyruvate + 4 ATP + 2 GTP + 2NADH + 2H+ + 6H2O -> glucose + 4ADP + 2GDP + 6Pi + 2NAD+ |
| phosphohexose isomerase is catalyzed by an active site _____ , does a _________ mechanism | glutamate, general acid/base |
| aldolase utilizes an active site _____ and forms a ______ intermediate | Lys, Schiff base |
| G3P dehydrogenase utilizes an active site ______ and forms a _________ intermediate | Cys, thioester |
| for PG mutase, ______ is post-translationally modified to _____ | His, phosphohistidine |
| TPP is derived from vitamin _______ | B1 |
| fermentation is a general term for a process that _______ energy but does not ______ O2 or _________ of NAD+ or NADH | extracts, consume, change concentration |
| mammals ______ convert fatty acids to sugars | cannot |
| gluconeogenesis is primarily used for: | - cori cycle to provide glucose to muscles, provide brain with glucose |
| pyruvate decarboxylase involves ______ and _____ | biotin and Lys residue |
| If glycolysis and gluconeogenesis were simultaneously operating at high rates, this would: | consume ATP and produce heat (useless energy), a futile cycle |
| factors that determine the activity of enzymes regulate the ______ of enzyme and the _________ | amount, effective activity |
| isozymes are different ______ that catalyze ___________ reaction | enzymes, the same |
| living systems thrive by keeping some metabolic reactions ___________ | far from equilibrium |
| hexokinase I-III are inhibited by their product, _______ | glucose 6-phosphate |
| hexokinase IV is inhibited by a _________ that binds tighter in the presence of _______ | liver regulatory protein, fructose 6-phosphate |
| at low glucose levels, hexokinase IV is _______ so that the liver does not compete for the glucose | inhibited |
| PFK-1 is inhibited by _____, and is activated by _____ | ATP and citrate, AMP |
| F26BP _______ PFK-1, inhibits ______ | activates, F16BPase-1 |
| PFK-2 and FBPase-2 are catalyzed by ______, and reciprocally regulated by _______ | the same polypeptide chain, insulin and glucagon |
| xylulose 5-phosphate ______ PFK-2, ______ FBPase-2, which results in an ________ in F26BP levels, stimulating glycolysis | activates, inhibits, increase |
| ATP _______ pyruvate kinase | inhibits |
| the ________ of pyruvate kinase is ________ by the level of Mg+2 | activity, limited |
| F16BP ________ pryuvate kinase, guaranteeing completion of glycolysis | activates |
| alternative fates of pyruvate include: | - source of new glucose, source of acetyl-CoA |
| acetyl-CoA _____ glucose synthesis by activating pyruvate _______ | stimulates, carboxylase |
| acetyl-CoA is a ________ modulator of pyruvate dehydrogenase | negative |
| glucagon turns on ________ of glucose 6-phosphate and PEP carboxykinase | synthesis |
| insulin ____ several gluconeogenic enzymes in the _____ | turns off, liver |
| main goals of pentose phosphate pathway | - produce NADPH for anabolic reactions, produce ribose 5-phosphate for nucleotides |
| the oxidative phase of PPP contains ____ steps | 4 |
| net reaction of oxidative phase of pentose phosphate pathway | G6P + 2NADP+ + H2O --> R5P + CO2 + 2 NADPH + 2H+ |
| the nonoxidative phase of PPP converts ______ phosphates to ______ phosphates | pentose, hexose |
| transketolase and transaldolase are specific to _____ | the nonoxidative phase of PPP |
| transaldolase mechanism involves a ______ base between a _____ and substrate | Schiff, Lys residue |
| transketolase mechanism involved a _____ ring that stabilizes the carbanion | TPP |
| the image provides an example of a | transketolase reaction |
| the image provides an example of a | transaldolase reaction |
| NADPH _______ glucose 6-phosphate dehydrogenase | inhibits |
| when more NADPH than R5P is required, _______ | complete oxidation occurs, multiple passes through the entire PPP to generate 12 NADPH |
| when both NADPH and R5P are required, ______ | oxidative phase only to generate R5P and 2 NADPH |
| when more R5P than NADPH is required, _______ | nonoxidative phase only to produce 6 R5P, fatty acids aren't needed |
| when both NADPH and ATP are required, ________ | oxidative phase with products sent through glycolysis |
| glucose enters the glycotic pathway through what three enzymes? | - glycogen phosphorylase, glycogen debranching enzyme , phosphoglucomutase |
| glycogen phosphorylase works by catalyzing the attack of _______ at a glycosidic linkage | inorganic phosphate |
| glycogen debranching enzyme _____ and _____ | transfers, cleaves |
| the catalytic site of glucose 6-phosphatase in located | in the lumen of the ER |
| glycogen synthase promotes transfer of glucose from ____ to a nonreducing end of branched glycogen molecule | UDP-glucose |
| glycogen branching enzyme promotes transfer of fragment ______ residues away from nonreducing end of a glycogen branch having at least _____ residues | 6 or 7, 11 |
| ______ is the protein that catalyzes initial assembly of primer chain | glycogenin |
| glycogen phosphorylase exists in two forms: _______ | pentose, hexose |
| which is the active form? | a and b, a |
| insulin signaling pathways | - increases glucose import into muscles, stimulates the activity of muscle kinase, activates glycogen synthase |
| if glycogen phosphorylase is phosphorylated, then ____ is activated | gluconeogenesis |
| the image provides an example of a | transketolase reaction |
| the image provides an example of a | transaldolase reaction |
| NADPH _______ glucose 6-phosphate dehydrogenase | inhibits |
| when more NADPH than R5P is required, _______ | complete oxidation occurs, multiple passes through the entire PPP to generate 12 NADPH |
| when both NADPH and R5P are required, ______ | oxidative phase only to generate R5P and 2 NADPH |
| when more R5P than NADPH is required, _______ | nonoxidative phase only to produce 6 R5P, fatty acids aren't needed |
| when both NADPH and ATP are required, ________ | oxidative phase with products sent through glycolysis |
| glucose enters the glycotic pathway through what three enzymes? | - glycogen phosphorylase, - glycogen debranching enzyme, - phosphoglucomutase |
| glycogen phosphorylase works by catalyzing the attack of _______ at a glycosidic linkage | inorganic phosphate |
| glycogen debranching enzyme _____ and _____ | transfers, cleaves |
| the catalytic site of glucose 6-phosphatase in located | in the lumen of the ER |
| glycogen synthase promotes transfer of glucose from ____ to a nonreducing end of branched glycogen molecule | UDP-glucose |
| glycogen branching enzyme promotes transfer of fragment ______ residues away from nonreducing end of a glycogen branch having at least _____ residues | 6 or 7, 11 |
| ______ is the protein that catalyzes initial assembly of primer chain | glycogenin |
| glycogen phosphorylase exists in two forms: _______ which is the active form? | a and b a |
| insulin signaling pathways | - increases glucose import into muscles - stimulates the activity of muscle kinase - activates glycogen synthase |
| if glycogen phosphorylase is phosphorylated, then ____ is activated | gluconeogenesis |
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daniellajoseph
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