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80 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Blood glucose can come from the (name 2 locations) |
intestines or the liver |
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Describe the phosphate grps of ATP (its composition & the significance of its hydrolysis)
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Contains phosphoanhydride bonds (phosphate acids linked together by a oxygen atom); hydrolysis of this bond (which is spontaneous & exothermic) can provide E required to less favorable rxn -rxn coupling. Cells must constantly maintain functional levels of ATP to power metabolic rxns |
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How does cytosolic NADH transfer its electrons? |
cystolic NADH can't cross the inner mitochondrial membrane. Thus one of two available shuttle mechanism to transfer electrons in the mitochondrial matrix must be used: 1.glycerol-3-phosphate shuttle: electrons are transferred from NADH-->G3P. These electrons can then be transferred to mitochondrial FAD, forming FADH2; FADH2 transfers its electrons to ETC via complex II, thus generating 1.5 ATP 2. malate-aspartate shuttle: electrons are transferred from NADH-->malate. Malate can then cross the inner mitochondrial membrane and transfer the electrons to mitochondiral NAD+, forming NADH; NADH transfers its electrons to ETC via complex 1, thus generating 2.5 ATP |
G3P & NADH; malatate & FADH2 |
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Ketone: What is it made from; what is it a transportable form of; what happens when there is a significant increase in ketone levels in the blood |
-Acetyl-CoA typically used to produce ketones when PDC is inhibited. (the reverse can happen, as well) -Ketone bodies are essentially transportable forms of acetyl CoA. -can lead to ketoacidosis (a potentially dangerous medical condition, occuring mostly with fatty acid breakdown in type 1 (insulin dependent) diabetes mellitus. |
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The glycogen in the liver and the skeletal muscle serve 2 different roles. What are they? |
1. Liver glycogen is broken down to maintain a constant level of glucose in blood 2. Muscle glycogen is broken down to provide glucose to the muscle during vigorous exercise
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The __1__ maintains glucose levels in blood during fasting through either __2__ or __3__.The __4__ can also carry out __5__ ,although it's a much __6___ contribution.These pathways are __7__ & __8__, which act to raise blood sugar levels,and are inhibited by __9__. |
1. Liver 2. Glycogen 3. Gluconeogenesis 4. Kidney 5. Gluconeogenesis 6. Smaller 7. Glucagon 8. Epinephrine 9. Insulin |
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Glycogen syn & degradation occur primarily in __1___ & __2__. |
1. Liver 2. Skeletal muscle |
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Pyruvate from aerobic glycolysis enters __1__,where it may be converted to __2__ for entry into the citric acid cycle if ATP is needed, or for __3__ if sufficient ATP is present. |
1. mitochondria 2. acetyl coa 3. fatty acid
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What is glycogen? |
-glucose polymer found in muscle & liver cells & main form of carbohydrate storage in animals |
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When does gluconeogenesis occur? Where does it occur? What does it involve? |
-when dietary sources of glucose are unavailable, and when the liver has depleted its stores of glycogen & glucose -occurs in liver (mainly) & kidneys (lesser extent) -involves converting non-carb precursors into intermediates,eventually becoming glucose. |
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Glucose flow: -Immediately after a meal -Few hrs after a meal
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-Intestines are source of abundant glucose. Body actively works to store glucose (via glycogenesis). Extra glucose is also converted to fatty acids & stored as triglycerides (in adipocytes). -Liver becomes primary supplier of blood glucose. Does this 2 ways: 1) Glucogenolysis (break down glycogen stores) 2) Gluconeogenesis (manufacture new glucose from non-carb molecules) |
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Where does Triglyceride syn occurs happen?
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-Liver (mainly), adipose tissue (a little) & small contribution directly from the diet
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Describe the syn of VLDL
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In the liver, triglyceride packaged & sent to adipose tissue as VLDL,leaving only small amount stored as triglyceride.
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What's the main purpose of fatty acid?
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It's used primarily by the body for fuel (supplied primarily by diet). Xs carb & protein converted to fatty acids and stored as E reserves in the form of triglycerol.
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Chylomicrons' purpose & what does it primarily carry
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transport dietary triglycerides & cholesterol from intestines into tissues; primarily carries triglycerides
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VLDL's purpose & what does it primarily carry
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Transports triglycerides from liver to tissues; produced & assembled in the liver; primarily carries triglycerides
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HDL's purpose & what does it primarily carry
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picks up cholesterol accumulation in blood vessels, deliver it to liver & steroidic tissues; it primarily carries cholesterol
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What's IDL?
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An intermediate (transition state) btw VLDL & LDL
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What's HDL and what does it primarily carry?
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It primarily carries cholesterol
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How are lipoprotein named (and based on the reason of how it's named, put the lipoproteins in order) |
-Named according to their density, which increases in direct proportion to the percentage of protein in the particle -Chylomicrons < VLDL < HDL |
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The F(x) of lipoprotein
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While free fatty acids are transported through the blood in association w/ albumin, a carrier protein, triglycerol and cholesterol are transported in the blood as lipoprotein
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What are the 4 things cholesterol plays a role in syn?
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1. Cell membrane 2. Steroid hormones 3. Bile salts 4. Vitamin D
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What's the purpose of LDL and what does it primarily carry?
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-It delivers cholesterol to tissues for biosyn (thus cholesterol is what it primarily carries by default). Majority of the cholesterol measured in blood is associated with LDL
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What are the 2 membranes of the mitochondria and what is it composed of?
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Inner & outer membrane, both composed of lipid bilayer (the inner membrane is folded into cristae. It extended into the matrix: the innermost space of the mitochondrion)
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Where are the following located: Kreb Cycle PDC ETC
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Kreb & PDC: located in the matrix ETC & ATP synthase: bound to the inner mitochondiral membrane
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where does protein breakdown begin |
within the small intestines |
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the final small amino acid chains are cleaved by enzymes of ______________ |
the brush border, in order to be absorbed & released into circulation by instestinal epithelial cells |
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amino acid breakdown begins with the removal of ___________ |
nitrogen grp, producing ammonia & a carbon chain. ammonia becomes urea, which is excreted in the urine. the remaining carbon "skeleton", alpha-keto acid, can be converted to pyruvate, acetly-CoA, or one of the Kreb's (TCA) cycle molecules (called "intermediates"). The exact fate of an amino acid depends on its carbon skeleton |
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Significance of NAPH |
important reducing agent in many anabolic processes |
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disulfide bonds |
important component of teritary structures; it forms when 2 cysteine molecules become oxidized to form cystine |
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describe the 4 diff protein structures |
1.primary: linear sequence of AA stabilized by peptide bonds 2.secondary: stabilized by H bonding btw amino grps & nonadjacent carboxyl grps; the 2 main second sturctures are alpha-helix & beta-pleated sheets (both a result of H bonding) 3.teritary: primarily result of moving hydrophobic AA side chains into the interior of the protein 4.quaternary:only exist for proteins with more than 1 polypeptide chain |
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what is the relationship btw Km & enzyme's affinity |
indirect |
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what does a low Km mean |
that not very much substrate is required to get the rxn rate to half the max rate thus the enzyme has a high affinity |
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mixed type inhibition |
inhibitor can bind to either the unoccupied enzyme or the enzyme-substrate complex; involves allosteric binding |
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what happens for the following snerios: (a) if enzyme has greater affinity for inhibitor in free form (b) if the enzyme substrate complex has greater affinity for the inhibitor (c) equal affinity to both forms |
-enzyme will have a lower affinity for the substrate similar to competitive inhibitor (Km increases) -Enzyme will have a greater affinity (Km decreases) for the substate -Would become a noncompetive inhibitor |
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what's the committed step in glycolysis |
the conversion of F6P-->F1,6BP (because PFK is the key biochemical valve controlling the flow of substrate to product in glycolysis) |
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what effect would you think a high concentration of atp would have on PFK activity |
when energy (ATP) is abundant, the cell should slow glycolysis. High concentrations of ATP inhibit PFK activity by binding to an allosteric regulatory site. it's interesting to note that since ATP is a reactant in the rxn catalyzed by PFK, you would expect a high concentration of ATP to increase rate of the rxn (Le Chatelier's principle). However the inhibitory allosteric effects of ATP on PFK outweigh this thermodynamic consideration. Of course if ATP level went too low rxn wont proceed at all |
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what are osteroid hormones? |
Steroids that act like hormones |
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what are osteriod hormones secreted by & what are they secreted into |
secreted by endocrine glands into the bloodstream then they travel on protein carriers to distant sites, where they can bind to specific high affinity receptors & alter gene expression levels |
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when is an ezyme saturated? what is it denoted? |
when there is so much substrate that every active site is continously occupied, and adding more substrate doesn't increase the rxn rate at all; it's denoted Vmax |
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what is the significance of Km |
it gives info on the affinity of the enzyme for its substrate [half of Vmax] |
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what happens to triglycerides in a fasting state (around the time of gluconeogenesis) |
triglycerides are broken down in the cell by lipase (hydrolyzes triglycerides & releases free fatty acids into the bloodstream). The fatty acids released are then taken around the body to various tissues that use them for beta oxidation. in times of extreme starvation, the body will also turn fatty acids into ketone bodies in the liver |
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Prosthetic group of PDC |
nonprotein molecule covalently bound to an enzyme's active site. the PDC with TPP (thimine pyrophosphate) prosthetic grp at 1 of its active sites. The thiamine in TPP is vitamin B1. It's a type of coenzyme (organic cofactor (enables enzyme's functioning)). |
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what would happen in thiamine deficiency in anerobic conditions? |
it would shut down both PDC & krebs cycle since both of these processes require thiamine in their TPP prosthetic grp. Without PDC & Krebs, amy NADH & FADH2 (with ETC obviously reduced) & ATP production would fall in order to compensate & maintain ATP, glycolysis rate would increase |
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the significance of atp synthase |
when protons from the intermembrane space go thru the atp synthase, causes it to syn atp thus atp production is dependent on a proton gradient. thus the overall process of electron transport & atp production is coupled by the proton gradient. |
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what happens when the proton gradient is destroyed |
no atp will get made from glucose breakdown |
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in the liver, what happens when: (a) excess acetyl coa & high blood sugar (b) excess acetly coa & low blood sugar |
-the excess becomes fatty acids in the cytosol -ketogenesis |
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what metabolic processes should you consider after: (a) a few hrs after you eat (b) extreme starvation |
-gluconeogenesis, glycogenolysis & beta oxidation -ketogenesis |
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describe how the ETC works |
it's a grp of 5 electron carriers. each member of the chain reduces the next member down the line. the chain is organized so that the first large carrier receives electrons (reducing power) from NADH.The fifth carrier of the chain must pass its reducing power to oxygen, reducing it to water (an end product of ETC) |
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what are the carriers of the ETC |
NADH dehyrogease (aka coenzyme Q reductase), ubiquinone (aka coenzyme Q), cytochrome C reductase, cytochrome C and cytochrome C oxidase |
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what happens in glycolysis? what is not required? |
involves "glucose splitting" glucose is partially oxidized while it is split in half into 2 pyruvate acid molecules, sm ATP & NADH amt, occurs in the cytoplasm; doesnt require oxygen |
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what is fat and what is it also known as? |
storage form of fatty acid aka triglyceride |
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what's its composition of fat |
3 fatty acids esterified into glycerol molecule |
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in what special way should fatty acids be formed |
must be stored in relatively inert form of fat becuase free fatty acids are reactive chemicals |
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what's the metabolic effect of the body going in flight or fight mode |
elevated levels of epinephrine trigger glycogenolysis in both liver & muscle in order to provide rapid surge of E needed to respond to stimulus |
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what do high NAD+ concentrations indicate |
E deficit and acetly coA production |
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is there a limit to the use of anaerobic glycolysis as an E source? |
yes: the ethanol or lactate that's produced builds up, having no other use inthe cell & acts as a poison at high concentrations |
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what happens to the lactate in human muscle cells after a period of strenuous excercisec |
the cori cycle: glucose is converted to lactate in red blood cells and lactate is converted to glucose in liver cells |
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describe the process of protons moving before atp synthase is utilized |
protons pumped out of the matrix-->intermembrane space. The inner mitochondrial membrane is highly impermeable to protons thus ETC with large proton gradient with pH being high (low proton concentration) inside the matrix than the rest of the cell |
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how can fatty acids be used |
1. beta oxidation 2.ketogenesis *note: ketones aren't substartes for glyconeogenesis, beta oxidation is |
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what happens in glycolysis? what doesnt it require |
involves "glucose splitting". Glucose is partially oxidized while it's split in half into 2 pyruvate acid molecules, sm amt ATP & NADH, within the cytoplasm; doesnt require oxygen |
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Regulation of the krebs cycle |
Glycolysis and glycogen metabolism are under complex sys of allosteric & hormonal control. Krebs cycle, in contrast, are regulated by 1. Substrate availability: can change rates 2. Allosteric regulation: changes efficiency of enzyme -all of the regulatory enzymes of the citric acid cycle, including by NADH -ATP allosterically inhibitor of PDC & isocitrate dehydrogenase (krebs) (krebs) |
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Glucagon does... |
Glycogen related actions get suppressed in the liver |
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what is the precursor of ketogenesis |
oxaloacetate (acetyl coA can't yield it, thus it can't stimulate it) |
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How do competitive, non competitive & uncompetitive inhibitors differ by where they bind and how they affect Vax and Km? |
Competitive: bind at active site; don't change Vmax; increase Km Noncompetitive: bind at allosteric site; reduce Vmax; doesn't change Km Uncompetitive: bind to the enzyme/substrate complex; reduce Vmax; reduce Km |
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How many total ATP are made per glucose for aerobic respiration? How many for fermentation? |
Total ATP per glucose for aerobic respiration =30 (eukaryotes) or 32 (prokaryotes). Total atp for fermentation =2 |
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What are the end products of fermentation for yeast? For muscle cells? |
Yeast=2 ethanol, 2 atp. Muscle cells= 2 lactic acid, 2 atp |
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What are the main steps in regulation for gluconeogenesis? For glycogenesis/glycogenolysis? For the Penrose phosphate pathway? |
The main regulatory steps for gluconeogenesis are the enzymes PFK & F-1,6-BPase. Generally speaking an abundance of atp or a lack of glucose stimulates gluconeogenesis. Glycogenesis is stimulated by insulin (stimulates glycogen synthase) and glycogenesis is stimulated by glucagon. The ppm is regulated primarily by NADPH; high levels turn off the pathway while low levels stimulate it . The ppm is regulated primarily by NADPH; high levels turn off the pathway while low levels stimulate it . The ppm is regulated primarily by NADPH; high levels turn off the pathway while low levels stimulate it . The ppm is regulated primarily by NADPH; high levels turn off the pathway while low levels stimulate it |
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zygomen |
inactive precursors of the active enzyme. in order for these enzymes to become active, they must first undergo some type of proteolytic activation (which is an irreversible step) |
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chymotrypsin |
the active form of the enzyme. In the inactive form of this enzyme (the zymogen) is synthesized in the pancreas and is called chymotrypsinogen. Once chymotrypsinogen is syn in the pancreas it is secreted into the intestinal tract where it is activated by a proteolytic enzyme called trypsin. The activated enzyme, chymotrypsin, can then hydrolyze proteins found in the intestine. |
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Explain the mitochondria's proton composition |
the concentration of protons in the matrix is lower than the concentration of protons in the intermembrane space. This leads to an electrochemical gradient being established between the intermediate space and the matrix. Gradients gave the potential to do work. That potential is utilized for the syn of ATP. |
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Competitive inhibitors |
Compete with substrate for binding at the active site. -can get to same Vmax but need more substrate to get there -inhibition can be overcome by adding more substrate thus outcompete inhibitors -km increases -structurally competitive inhibitors must at least resemble the substrate |
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Noncompetitive inhibition |
Binds at allosteric site, not at active site thus no matter how much substrate you add, the inhibitor will not be displaced from its site action -Vmax & 1/2 Vmax diminish but Km stays the same b/c substrate can still bind to active site but inhibitor changes catalytical activity of the enzyme |
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Cooperativity |
Special type of allosteric inhibition: one active site acts as an allosteric regulatory site for other active sites |
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If you see a line with the same Vmax as original but a reduced rate of product formation, think what type of inhibition |
Competitive inhibition |
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If you see a line with a lower Vmax than the original & a reduced rate of product formation think what type of inhibition |
Noncompetitive inhibition |
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Uncompetitive inhibition |
If an inhibitor is only able to bind to the enzyme-substrate complex (can't bind before the substrate has bound) -Vmax decreases bc it limits the am of available enzyme-substrate complex that can be converted to product -Decrease Km bc it sequester enzyme bound to substrate, decreasing affinity of enzyme for the substrate |
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Why does competitive inhibition Vmax doesn't change but for noncompetitive, uncompetitive & mixed type it does |
Vmax decreases for the others bc they can be overcame by adding more substrate bc dealing with allosteric inhibition |
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