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145 Cards in this Set
- Front
- Back
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What does Pentose pathway produce is it oxidatitve?
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YES---produces Ribose-5-phosphate--the pentoses are used in nuleotide synthsis of RNA, DNA, and NADH is used to coutner the damagin effets of oxygen radicals
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What happens in Glucose-6-phosphate dehydrogenase deficiency
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NADPH production is is dimished, and detoxification of H2O2 is inhibited and superoxide free radials form
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Why Glucose 6-phosphate dehyrdogenase deficiency favored for malaria
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b/c the parasite is very senstive to oxidative damage
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What does the nonoxidative phase of pentose phosphates do and why
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recycles pentose phosphate to glucose 6-phosphate--wants to generate more NADPH
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How amyn NADPH are formed in pentose phosphate pathway
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2
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What controls entry of glucose 6-phosphate inot the pentose phosphate pathway
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determined by the relative concentrations of NADP+ and NADPH
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What are 3 stages of Celluar respiration?
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1. oxidation of carbs, fatty acids, adn aa to produce AcylCoA
2. the acetyl groups are fed in CAC for oxidation to CO2, oxidation relased electrons carried by NADH, adn FADH 3. Electrons are transferred to electron carring molecues (respiratory chain, to reduce O2 to H20 |
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What is oxidative phosphrolation
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the energy released is used to produce ATP
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Fatty acids and Amino acids are directly oxidized to form acetyl CoA, but how is Glucose converted to Acetyl CoA
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by pyruvate dehydrongenase complex
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What is MOA for pyruvate being oxidated to acetylCOA
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a carboxyl group is removed from pyruvate, releasing CO2--then the 2 carbon fragment joing with CoA to form actyl COA
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Why does Coenzyme A have a reactive thiol group
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thiols have high strandards of free energy--get more energy from thiol group--as b/c pyruvate has 2 oxygen which can under resonance,--which means more stablized--so releases less energy
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What are the 3 enzymes that compose the Pyruvate dehydrogenase complex
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Pyruvate dehydrongenase (e1), dihydrolipoyl tranacetylase, and dihydrolipoyl dehydrogenase
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What are 5 cofactors and locations
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Thiamine pyrophosphate, lioaamide, FAD, NAD+, and CoA---located in mitochondrial maxtrix
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What is unique about pyruvate
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penetrates the mitochondrial membrane
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What is 1st stage of Citric acid cycle
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Actyl-CoA undergoes oxidation by a condensation reaction removing water--then 2 carbon fragment binds with OAA- to form Citrate
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Where 2 stages form stuff in Citric acid cycle
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oxidation of isocitrate to alpha ketoglutatrate, and alphs ketoglutarate to succinyl-CoA, and NADH formed here as well
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NADH is primarly formed, but also can NADPH be formed
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YES, usually not
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Where is ATP or GTP is equilalent generated in Ctirtic acid cycle
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Succinyl-CoA to Succinate
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Where is FADH2 generated
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succinate to fumarate
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Where is final NADH formed
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conversion of Malate to OAA
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What are final products formed in CAC
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3 NADH, 1 FADH2, and ATP equialavent
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What are 2 reasons citric acid cycle is so complicated
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1. 4 & 5 carbon end products of many catabolic process feed into the cycle to serve as fuel
2. intermidates of this are drawn out to be used as precuroses in a variety of biosythetic pathways |
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WHat are anaplerotic reactions
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reaction that replace the various intermediates that have been drawn out--helps keeps the concentrations of citric acid cycle intermediates constant
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What is most anaploertic reaction
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occur in liver and kidney when OAA is low in the Citric acid cycle--, pyruvate is carboxoclized to form more OAA
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What 2 levels control regulation of the citric acid cycle
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converions of pyruvate to acetyl CoA (pyruvate dyhyondase complex), and entry of Acetyl-CoA into citrate by citrate synthase
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What do AMP, CoA, NAD+ adn ADP do
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up regulate citric acid--make it run
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What does ATP, acetyl-CoA, and NADH, adn fatty acids to
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inhibit citric acid cycle
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What happens when aspartate and glutamate proteins are degraded?
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Gluatmate--forms alpha ketogluatrate, and asparate forms oxaloactate--both which are fed into the cycle
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What does oxidative phosphortylation involve
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the reduction of O2 to H20, with electrson donated by NADH and FADH2
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In euks were does electrons transport and oxidative phosphorylation occur
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in mitochondria
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Which memembrane is more permable in mitochondria
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outer---
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The inner membrane is IMpermeable to most small mocleules, what does it bears
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componeents of the respiratory chain, and ATP synthase
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What is enclosed in mitochondrial maxtrix
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pyruvate dehydronase complex and its cofactors, and NADPH, NADH
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What are dehydrongeanses and what do they do, and specific foe
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dehydronases collect electrons from catabolic pathway---and specifically funnel them into NAD+ the electron acceptor
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Where is NAD+ located
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cytosol, and mitochonrdia
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NADH and NADPH are water soluble--and how to do they associate with dehydrogenases
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reversibly
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Where does NADH carry electrons from and to
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from catbolic reactions---to respiratory chain
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What type of reactions does NADPH supply electrson to
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anabolic reactions
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Can NADH of NADPH penetrate the miochondrial membranes
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NO--cannot escape
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What makes the outer memebrane relatively permeable to a nubmer of different orgainic molecule
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the trans-membrane protein called porin
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What is the inner membrane impereable to
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most ions and polar moceules
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What is benefit of imperabillity of inner membrane
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establishes steep chemical gradients between the maxtrix and the intermembrane space
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The oxidation of carbohydrates, fatty acids and amino acids results in production of
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acetyl coA
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NADH generate how much ATP, and how much ATP from FADH2
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2.5=NADH, and 1.5 from FADH2
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What happens when NADH gives up its electron to Complex I
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1. a hydride ion( 2 electrons are given to Ubiquione (Q)( a mobile carrier, and transfer of 4 protons from the matrix to inermembrane space
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What part of Complex I is endergonic, and what is exergonic
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exergonic--transfer of hydride
endergonic is hydrogen transfer |
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What gives up its electrons to Complex II and where does it send
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FADH2---from the conversion of succinate to fumerate--sends to Ubuquione (Q) a mobile carrier transfer electrons to complex III
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WHat happens in Complex III
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Q transfer electons to complex III--one at a time transfer to cytochrome C (helps make swich between 2 electron carrier ubuquione and one electron carrier cytochrome C
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What happens in Complex IV
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cytochrome C transports one electron at a time to IV--then tranfers electrons into maxtrix, binds with O2 and forms water.. and 2 H+ pumped into intermembrane space
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What Complexes pump Hydrogen
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I, III, IV
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How much total Hydrogen is pumped in intermembrane space
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10 protons, 4 from I and III, and 2 from IV
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What prostheic grops composed complex IV
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hema alpha and heme alpha 3
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Is complex IV very effecticent in FULLY reducing O2
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YES
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02 +e- to 02- is an example of
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a superoxide anion (higly reactive
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What is equation for full reduction of oxygen
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02 + 2e- = H20
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What is complex I equation
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NADH + H+Q---NAD+ QH2
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What is summary equation for respiratory chain
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NADH +H + 1/2 02--NAD+ + H20
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What complexes make up ATP synthase
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F1 and F0
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What is F0,
and what is F1 |
FO-the proton pore
F1-catalyzes ATP syntheisis |
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What 2 things drive ATP syntheisis
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pH gradient H+, and transmembrane potential
electrical gradient |
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What is pH in intermembrane space vs inside (matrix
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intermembrane (ACIDIC)
inside (alkaline, basic) |
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What is electrial potietnal in intermembrane space vs inside maxtrixx
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intermembrane--+
maxtrix---(negative) |
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Can ATP and ADP freely cross the inner membrane
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NO they are HIGHLY charged
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How do ATP and ADP cross inner membrane
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adeneine translocase
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What does adeneine transport do
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antiport---it allows ADP into the mxtrix--and allows ATP to leave the maxtrix
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What type of transporter is phosphate translocase
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symport (2 in) one H+ into matrix, and one phosphate (H2PO4)
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IS ADP/ATP translocator an abundant proteint in the membrane
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YES
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What does ADP/ATP translocater depend on for function
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25% of energy from electron transport
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What also drives ADP/ATP translocater
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(electrochemical gradient as ATP has one more negative charge, then ADP, so ATP is pulled out, and ADP pulled in
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If NADH cannot penetrate mitochondria--how does NADH generated from glycolsis in cytosol be reoxidized?
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indirect shuttle
1. Malate-aspartate shuttle 2. Glycerol-3-phosphate shuttle |
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What is the most ACTIVE shuttle in the liver, kidney, and heart mitochonrdia
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Malate-aspartate shuttle
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How does Malate-asprate shuttle work
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NADH gives up a H+ to OAA to form malate by malate dehydrogenase
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The malate forms then pass though the inner membrane via what transporter
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Malate-alpha ketogluatarate transporter
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What is point of Glutamate-aspartate transporter
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after Malate enters Maxtrix-NADH recovered, reforming OAA-OAA can't leave maxtrix--so converted to aspartate--which exits the maxtrix
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How much energy does Malate shuttle produce for one NADPH
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2.5 ATP
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What organ use the Glycerol 3-phosphate shuttle
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skeletal muscle and brain
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How does Glycerol-3-phosphate shuttle work
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NADH b/c NAD, to FAD to FADH2-then FADH2 electrons are donated to Q--then complex III
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How much ATP does Glycerol-3-phosphate prodcue
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1.5
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What shuttle does not require a specific transporter
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Glycerol-3-phosphate
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What is electon acceptor in Glycerol-3-phosphate shuttle
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FAD--from NADH b/c NAD
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Why does Glycolsis produce either 3 or 5 ATP
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depends on shuttle that was used for NADH+
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How much ATP is yielded per glycose
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30-32
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What happens in Cyanide poisoning of inhalation of HCN or KCN
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CN binds to Fe+2 of complex 4, shuts down ETC
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Why must Cyanide poisonig be treated with converting Fe+2 to Fe+3
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convert to Fe+3---CN cannot bind
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Glycogen is the primary storyage form of
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glucose in mammals
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Where are the main depots of glycogen stroage are found in
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liver, and msucle (highest is liver per gram--(but more muscle so overall more glycogen in muscle
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Where does Glycogen degradation being at
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non-reducing end of glycogen
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What enzyme breaks down glycogen, and product
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glycogen phoshorylase--to form glucose-1-phosphate
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The released sugar from glycogen breaked down is phosphorlated what pay for this
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the energy release from breaking the glyosidic bond
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Glycogen phosphorylase acts repetiviely on the nonreducing ends on glycogen branches until it reach
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4 residues away from 1-6 branch point
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What does debranching enzyme do
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transfer 4 terminal residues to the adjacent branch exposes 1-6 linkage
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What enzyme breaks the 1-6 linakage
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alpha 1-6 glycosidase
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What happens after 1-6 linkage is broken
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branched structure is converted into a linear sturcutre, which can further degrage by glycogen phosphorylase
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What is end product of glycogen degredation
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Glucose 1-phosphate
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Where can Glucose 1-Phosphate make
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Glucose-6-phosphate
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What enzyme makes Glucose-1-phosphate to Glucose-6-phosphate
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phosphoGLUCOmutase
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Glycogen makes Glucose-6-phosphate for 2 reasons
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enter glycosis, or in liver replenishes blood glucose
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What enzyme allows glucose-6-phosphate to become glucose in liver
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glucose-6-phosphatase
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Does Glycogen synttheis occur by reversal of glycogen degrradation
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NO
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What is the precursor for glycogen synthesis and form
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UDP-glucose--ACTIVATED FORM of glucose
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How does a Sugar Neuleotide form
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Sugar phosphate bind to NTP, this releases Pyrophosphate--which release lots of energy
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How is a new gluocgen moecule initaited and what does it require
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the protein glycogenin--primer --the glycogenin is enzyme and primer
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What enzyme adds glucose reisdues to glycogenis primer
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glycogen synthase
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How does glycogens syntthase do
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promotes transfer glucose reisdure from UDP glucose
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To iniatie glycogen synthesis, the glucose-6-phosphate is converted to glucose-1-phosphate, glucose-1-phosphate is converted to
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UDP-Glucose
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What does UDP-Glucose do
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donates its glucose residue to end of glycogen molecule
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What limits the size of the glycogen granules
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glycogen synthase recognizes the primer, and can only add glucose when it is in contact with primer (glyycogenin)
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Glycogen synthase catlyzes only the synthesis of what type of linkage
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alpha 1-4
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What does branching enzyme do
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BREAKS exisitng alpha 1-4 linakage and forms alpha 1-6 linakages
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What are the 2 benefits of branch of glycogen
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1. increase the solubility of glycogen and the number of site accesible to glycogen phosphorylase and glycogen synthase-(both as non-reducing ends)
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What does glycogen phospharylase do, what does glycogen synthase do
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BREAKS down GLYCOGEN
SYNTHASE--MAKES GLYCOGEN |
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What forms does allosterically regulated glycogen phosphorylase exists in, what form is more active
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phosphorlase A (more active)
phsophorlase B (less active |
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How can glycogen phosphorylase convert between a and b, which is active
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porphorylation of a single serine reside in each subunit--removed a serine makes ACTIVE
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What does does phosphorlase kinase do
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cause conversion from B(non-active) to A--which breaks down glycogen
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What regulates Glycogen phosphrylase phosphatase do
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Converts Phosphorylase A (active) to B (inactive)--for resting muscle (don't need glycogen breakdown)
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Explain regulation by of Glycogen Phosphorylase in Liver with phosphrylase a
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acts a glucose sensor, 2 allosteric binding sites for glucose as blood glucose increases, causes conformation change of glycogen phosphorlase a, to b (less active) (don't need to break down glyogen when glucose is present)
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The phosphorylase kinase is controlled by and lead to
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CAMP via adenylate cyclase--leads to breakdown of glycogen
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When glyocgen is broken down in liver where is it release vs muscle
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liver--realease glucose in blood, muscle glucose enters glycolsis
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What is different about phosphorlyation of glycogen SYNTHASE
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when phosphorlated, it is inactivated!!!
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WHat is glyconeogensis?
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glucose is made from non-carb precursors
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Gluconeogensis is what type of pathway, as does it require energy
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anabolic pathway REQUIRES energy input
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Can both gluconeogensis and glycolsis occur at same time
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NO, stimulation of one, other is inhibited
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The energy requireing steps of gluconeogensis are coupled to ATP utlizatoin, and thus made
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irrerversible
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Are regulatory step reversible
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NO---IRREVERSIBLE
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What are 2 fates of pyruvate
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converted to actyl co-A or be converted OAA to start gluconeogensis
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What inhibits glycosis, and stimulates gluconeogensis
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acetyl-CoA inhibtis glycosis, and stimulate gluconeogensis
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What is the first bypass reaction of gluconeogenesis
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conversion of pyruvate to phosphoenolpyruvate PEP
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The first bypass of Gluconeogenesis is the predominat pathway when what is present
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pyruvate or alanine
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What parts of the cell does Gluconeogensis occur
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cytosol and mitochondria
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Are alternative pathways at the first bypass
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YES
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What is the second bypass
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conversion of fructose 1,6 bisphopahte to fructose 6-phosphate by fructose 1,6 bisphosphatase
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What is fructose 2,6 biphosphates role in gluconeogensis
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ftucutose 2,6 bisphophate--activates glycolysis, and inhibit gluconeogensis
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What catalyzes third bypass
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glucose-6-phosphatase
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Why isnt 3rd bypass regulated by hexokinase like glycolsis
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cost energy, b/c wpi;d meed to form ATP
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Is Gluconeogensis expensive? How much energy is consumed
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4 ATP, and 2 NADH
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What makes Gluconeogensis favorable?
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energy released from converting 4 ATP to 4 ADP--makes G <0
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What is Gluconeogenesis reaction?
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2 Pyruvate + 4ATP +2NADH----Glucose
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What other things are gluconeogenic
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many amino acids are gluconeogenic---can be converted to glucose
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Are fatty acids gluconeogenic
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NO--cannot convert to Glucose
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Are glycolsis and gluconeogensis co-regulated and example
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YES, AMP activates glycolsis,and inhibit gluconeogensis
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What happens after vigrous expercise in muscle, and glycogen is depleted
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No O2--so lactate is produce
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What is benefit of generating lactate
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NADH cannot be reduced without oxygen---so NADH is converted back to NAD+
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What happens after lactate is produced
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returns to liver and is converted into glucose by gluconeogensis
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What happens after glucose is reproduced in liver
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relased back to muscle--and stored as glycogne
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What is the Cori Cycle
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recycling of lactate--back to glucose
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