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77 Cards in this Set

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What are the 2 major goals of metabolism
1)extract energy and reducing power from environment
2)synthesize building blocks needed to make more complex polymeric macromolecules
What are the characteristics of catabolic pathways
1)generally oxidative
2)breaking covalent bonds
3)result in release of energy
What are the characteristics of anabolic pathways
1)generally redective
2)bond formation
3)consume energy
What are some examples of oxidative catabolic pathways
glycolysis, FA oxidation
What are some examples of non-oxidative catabolic pathways
glycogenolysis, hydrolysis of TGs to FAs
What is the universal carrier of acyl groups
Coenzyme A
What is the major function of skeletal muscle
mechanical work
Describe white muscle fibers in terms of their contraction speed, duration, capacity, aerobic oxidation and what they use as fuel
high contraction speed, limited duration, high capacity, limited aerobic oxidation (low mitochondrial content), use glycogen and glucose with lactate formation
Describe red muscle fibers in terms of their contraction speed and oxidative capacity
slow contraction speed, high oxidative capacity
Describe the heart in terms of contraction and oxidative capactiy
continuous contraction, high oxidative capacity
Rank white, red, and heart muscle fibers in terms of mitochondrial content from lowest to highest
white<red<heart
What is the main general role of the liver?
biosynthetic and detoxifying organ
Is the liver rich in mitochondria and poor in microsomal systems?
No, it is rich in both
Name 6 specific functions of the liver
stores glucose as glycogen, de novo glucose synthesis, urea synthesis, ketone synthesis, assembles lipoproteins, coordinator of fuel homeostasis
What are is the major work done by the brain and nerve?
ion pumping to maintain membrane potential for electrical activity
Describe the brain and nerve in terms of glycolytic and oxidative capacity?
High capacity of both.
What is the major and minor fuel source of the brain and nerve? What can they not use as a fuel source?
glucose, ketone bodies, FAs
What is the function of adipose tissue?
Storage, mobilization and synthesis of TGs
What is the major precursor of alpha-glycerol phosphate for tryglyceride synthesis?
glucose
What is the major function of the kidney?
fluid homeostasis: osmotic work, high rate of active transport, acid and base balace
What does the kidney use as fuel?
FAs, lactate, ketones
What are 2 minor functions of the kidney?
ammonia synthesis, gluconeogenesis
What is the main pathway of energy in RBCs and why?
anaerobic glycolysis b/c no mitochondria
Why do RBCs make 2,3 BPG?
regulate O2 affinity of hb
Rank the order of fat, protein, and glucose stores in the tissue of a normal adult.
glucose<protein<fat
Rank the order of fat and glucose stores in the extracellular fluid of a normal adult.
glucose<fat
What is more important in the body in terms of fuel metabolism after a meal? Replenishing glycogen stores or making fat
repleneshing glycogen stores
What are the 3 stages of energy extraction? How much energy is gained in each stage?
1)degrade macromolecule into building blocks, no useful energy gained
2)convert building blocks into common inermediate (Acetyl-CoA), small energy gained
3) terminal oxidation of acetyla-coA to CO2 and H2O, most energy gained
What 5 pathways occur in the cytosol?
glycolysis, PPP, FA synthesis, Nucleotide synthesis, protein synthesis
What 4 pathways occur in the mitochondria?
CAC, Oxidative phosphorylation, B-oxidation of FA, ketogenesis/ketone oxidation
What 3 pathways use both cytosolic and mitochondrial enzymes?
gluconeogenesis, urea synthesis, steroid hormone synthesis
What 4 pathways take place on SER?
TG synthesis, phospho/glycolipd synthesis, cholesterol synthesis, hydroxylation/detoxification reactions (p450)
One or more of what 3 properties is usually true for a highly regulated enzyme?
1)catalyze irreversible rxns
2)catalyze rate limiting step
3)catalyze committed step
What is a committed step?
first step that is committed solely to the formation of the product
What are 7 ways to regulate enzymes?
1)change abundance
2)alter pool size of sustrate
3)cooperativity
4)organization of enzymes into larger catalytic units
5)isoenzymes
6)altering kinetic properties of Enzymes with allosteric effectors
6)Regulation by covalent modification
What are 2 ways to change the abundance of an enzyme?
1)induction/repression of enzyme synthesis (transription level mostly)
2)degradation rate
What is the difference amongy a macromolecular complex, multifunctional protein, and metabolon? Give an example of each.
metabolon are a group of enzymes in a pathway located in close proximity but not tightly organized like macromolecular complex. CAD protein in pyrimidine synthesis is used for multifxnal complex.
What are the types of covalent modifications of enzymes?
phosphorylation(reversible), proteolytic cleave(irreversible)
what products are usually allosteric effectors?
end productos of pathways, metabolites that reflect energy status
Does proteolytic cleavage of an enzyme usually activate or inactivate cascade systems?
activate
What rxn does the enzyme myokinase/adenylate catalyze? Where is it most found?
ADP-->ATP+AMP...muscle myfibril
What is the reaction for energy charge?
(ATP+0.5ADP)/(ATP+ADP+AMP)
When E.C. begins to fall, what happens?
catabolic pathways are activated and anabolic pathways are inhibited.
T or F, the more negative the redox potential, the greater the tendency to lose electrons?
True.
T or F, the more negative the redox potential, the greater the tendency to gain electrons?
False.
T or F. A positive value for delta Eo indicates an exergonic reaction.
True.
T or F. A positive value for delta Eo indicates an endergonic reaction.
False.
NAD/NADH pair participate in the transfer of what?
H:-...hydride ion
FAD/FADH2 pair participate in the transfer of what?
2 hydrogen atoms
Describe in general dehydrogenases?
catalyze the transfer of H from substrate to coenzyme acceptor.
What are the 2 major classes of dehydrogenases?
Those requiring nicotinamide coenzymes and those requiring flavin coenzymes.
What are nicotinamide coenzymes made from?
niacin and tryptophan
what is the difference between NAD+ and NADP+
NAD+ is mainly in catabolic pathways that are mainly oxidative, NADPH is mainly in biosynthetic anabolic pathways usually reductive in nature. NAD/NADH concentrated in mitochondria while NADP/NADPH is in the cytosol
NAD-->NADH +H+ reactions help what types of reactions?
oxidation of alcohol to aldehyde or keto- groups
What is pellegra and how do you get it?
niacin deficiency, dermititis, diarrhea, and dementia
Where does flavin come from?
riboflavin
where is the semiquinone intermediate found?
Before transfer of second hydrogen in FAD/FADH2 rxns.
FAD-->FADH2 rxns help what types of reactions?
oxidation that creates carbon-carbon double bonds
what are oxidases?
catalyze transfer of electrons from an organic substrate to molecular oxygen via an intermediate carrier bound to the enzye tightly which is usually either metal ions or flavin nucleotides
oxidases using metal ions usally end up with what product? what about those using flavin nucleotides?
H2, H2O2
What are the major ROS?
O2-,H2O2,OH*
what does superoxide dismutase do?
2O2- + 2H+ -->H2O2+O2
what are the three SOD isozymes and where are they located?
Cu/Zn SOD(cytosolic), MnSOD (mitochondrial), ec SOD (extracellular)
What are two sources of H2O2?
formation by SOD, formation of H2O2 via oxidase-catalyzed ractions (fad dependent oxidases)
What does peroxidase do?
H2O2 + AH2-->2H2O+O2
What does catalase do?
2H2O2-->2H20+O2
how is most H2O2 destroyed in the body?
localized and destroyed in peroxisomes
why is H2O2 dangerous and where does it cause the most damage?
strong oxidizing agent...membranes
What enzyme in the citric acid cycle is not in the matrix?
succinate dehydrogenase
What is succinyl-CoA used in?
heme synthesis
What is OAA used in?
glucose synthesis.
What is citrate used in?
FA synthesis
What are ketoacids (OAA,alpha ketoglutarate) used in?
nonessential amino acid synthesis
what is malate used in?
gluconeogenesis
What does the accumulation of ATP, which indicates an energy rich state, do to the citric acid cycle?
Inhibits the cycle distal of citrate synthesis...accumulatation of citrate gets used in FA synthesis
What part of the CAC effects PFK-1, acetyl-CoA carboxylase, pyruvate carboxylase...and how does it effect these parts?
citrate inhibits PFK-1 and activates acetyl-CoA carboxylase (first step fatty acid synthesis. acetyl-coA activates pyruvate carboxylase (inital step for gluconeogenesis)
What's the overall reaction for the CAC?
Acetyl~CoA + 3 NAD+ + FAD + GDP + Pi + 2H2O -->
2CO2 + 3NADH + FADH2 + GTP + 2H+ + CoASH