Term
| What is the michaelis menton equation? |
|
Definition
| it experimentally relates reaction rates to substrate concentrations and allows calculation of Km and Vmax. It assumes saturation amounts of substrate . |
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Term
| If you want to quantify an enzyme, what would you saturate in your assay? |
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Definition
| You would saturate your substrate (substrate would be zero order, enzyme is first order) |
|
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Term
| If you want to quantify the substrate, what would you saturate in your assay? |
|
Definition
| you would saturate the enzyme (enzyme would be zero order, and substrate would be first order) |
|
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Term
| What is LDH and how do we measure it when we do an assay? |
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Definition
| LDH is lactate dehydrogenase, an enzyme. So we would saturate lactate and NAD+ in the assay, and measure NADH (product) through absorbance measurements in a spectrophotometer. |
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Term
| How many subunits does LDH have? What are the different combinations called? |
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Definition
| LDH has 4 subunits (M's and H's) which can combine in 5 different cominations to form isoenzymes. |
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Term
| When separating different LDH isoenzymes in electrophoresis, which ones move the fastest? |
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Definition
| LDH1's move the fastest, followed by LDH2, etc... |
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Term
| What LDH isozyme is present mostly in liver tissue? |
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Definition
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|
Term
| In a normal person, which LDH isozyme will be the highest concentration? |
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Definition
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Term
| IF a person had a heart attack, what would you see in the LDH isozyme assay? |
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Definition
| we would see the LDH1 would be in higher concetration than LDH2 (1-2 flip) |
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|
Term
| What do muscle and RBC's use LDH for? |
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Definition
| to convert lactate to pyruvate for use in energy metabolism |
|
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Term
| What would an izoenzyme pattern with high LDH4 and LDH5 indicate? |
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Definition
|
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Term
| What would an izoenzyme pattern of mostly LDH1 and LDH2 indicate? |
|
Definition
| hemolysis or heart attack |
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Term
| What would an elevated serum level of lipase indicate? |
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Definition
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Term
| If setting up a lipase assay, what compound would we saturate? |
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Definition
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Term
| The pancreas secretes lipase into the intestines. What does it imply if we find lipase in the blood? |
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Definition
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Term
| When we do a lipase assay, we measure absorbance at 340 nm. why? |
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Definition
| NAD+ is formed from NADH by the reaction in the assay. NADH absorbs at 340 nm. So, the more lipase is present, the less NADH is present in the assay, so aborbance at 340nm would DECREASE |
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Term
| What does elevated serum levels of amylase indicate? |
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Definition
| Normally, serum levels of amylase are very low, so elevated levels indicate tissue damage or pancreatitis |
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Term
| In an amylase assay we saturate oligoglucose dyes. what are these? |
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Definition
| they are short glucose polymers with a dye on it. |
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Term
| What do we see in an amylase assay with high amylase levels? |
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Definition
| the amylase digests the oligoglucose dye, and forms glucose + the dye, so we can see the dye only when amylase has cleaved it and we can measure the color in a spectrophotometer. |
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Term
| Why does the muscle tissue build up creatine phosphate as an energy reserve instead of just building up ATP levels? |
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Definition
| High ATP levels inhibit many metabolic pathways that we want active in muscle cells. |
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Term
| What does a high creatine kinase level in serum indicate? |
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Definition
| muscle damage (maybe muscular dystrophy or heart attack) |
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Term
| Creatine kinase has how many subunits and how many possible combinations? |
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Definition
| Creatin kinase has two subinutes (M and B) and can combine in 3 different isoenzymes. |
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Term
| What creatine kinase isoenzyme is present in the highest levels in muscle cells? |
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Definition
| muscle cells primarily have the MM isoenzyme, with some MB |
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Term
| What creatine kinase isoenzyme is present in the highest levels in heart cells? |
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Definition
| Cardiac muscle has a high MB percentage than skeletal muscle, but MM is still the majority. |
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Term
| What place in the body has a lot of the BB creatine kinase isoenzyme? |
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Definition
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|
Term
| higher than normal MB creatine kinase levels would indicate that it came from what tissue? |
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Definition
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Term
| what is the difference between peptide hormones vs steroidal or thyroid hormones. |
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Definition
| peptide hormones never make it inside the cell. They bind to cell surface receptors. The other two types diffuse right through the membrane and bind to internal receptors |
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|
Term
| What is a common mechanism of signal transduction? |
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Definition
| a phosphorylation cascade |
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Term
| Why do we have two mechanisms of signalling for peptide hormones vs. steroidal/thyroid hormones? |
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Definition
| peptide hormones are typically very hydrophillic, and thus cannot diffuse through the membrane and must have receptors. Steroid/thyroid hormones are typically hydrophobic, so they can diffuse through the membrane. STeroid/thyroid hormone ride around on serum proteins because of this hydrophobicity. |
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Term
| What is the G protein system? |
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Definition
| it is a system that stimulates the cAMP system, which stimulates a phosphorylation cascade. epinephrine and glucagon use this system |
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Term
| What are the properties of the G-protein receptor? |
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Definition
| it spans the membrane with 7 alpha delix segments, and it activates the second messenger system (cAMP or DAG, or IP3) |
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Term
| What does the G-protein bind to in order to produce cyclic AMP? |
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Definition
| the g protein binds to adenylyl cyclase, which makes the cAMP |
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Term
| How do we stop the chemical cascade that cAMP causes? |
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Definition
|
|
Term
| when is cAMP at its highest levels in humans? |
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Definition
| during fasting or starvation |
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Term
| The phosphorylation cascade that glucagon causes results in the activation of what? |
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Definition
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|
Term
| What are the properties of protein kinase A? |
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Definition
| inactively, it has 2 catalytic subunits, and 2 regulatory subunits. When cAMP binds to the regulatory subunits, they catalytic subunits change shape and detach and are not activated to go phosphorylate other proteins |
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Term
| What does glucagon cause to happen at the end of its phosphorylation cascade in liver cells? |
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Definition
| it promotes breakdown of glycogen |
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Term
| Muscle cells don't have a lot of glucagon receptors, so how do they know to start using their glycogen? |
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Definition
| the chemical cascade is set off by epinephrine. |
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Term
| What is the time difference in response between say glucagon (peptide hormone) and prednisone (steroid hormone) |
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Definition
| glucagon's effect is almost immediate, whereas prednisone effects transcription and might not make its full effect for several days. |
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Term
| What is the difference between a phosphatase and a kinase? |
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Definition
| a phosphatase usually DEphosphorylates, while a kinase phosphorylates. phosphorylation can activate or inactivate an enzyme. |
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Term
| what enzyme controls glycogen degradation? |
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Definition
| glycogen phosphorylase. the enzyme is fully activated when we have high AMP/low ATP (low energy) and when it is phosphorylated by glucagon. |
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Term
| glucagon ends up phosphorylating glycogen phosphorylase, which activates it. What other molecule does it phosphorylate? |
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Definition
| glucagon stimulates the phosphorylation of glycogen synthase, which INACTIVATES it. This makes sense because we don't want to synthesize glycogen at this time. |
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Term
| What is a receptor kinase? |
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Definition
| it is a receptor membrane protein that can phosphorylate things itself. |
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Term
| What are the properties of an insulin receptor? |
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Definition
| it is a tyrosine receptor, and has 2 alpha and 2 beta subunits. |
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Term
| How does insulin's signal transduction pathway work? |
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Definition
| It is a phosphorylation cascade (just like glucagon) that ends up phosphorylating protein kinase B. protein kinase B ends up activating a phosphatase that then ends up dephosphorylating a bunch of important enzymes. |
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Term
| What mechanisms does insulin use to cause its responses? |
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Definition
| its tyrosine kinase activity causes several events, including the reversal of glucagon's phosphorylations. It stimulates transport of glucose (GLUT 4's) in muscle and fat. insulin also effects change at the transcriptional level as well. |
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Term
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Definition
| they communicate and control the immune response |
|
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Term
| what receptor system to cytokines use? |
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Definition
| the JAK/STAT system. It is a tyrosine kinase. the JAK parts phosphorylate each other and the receptor, the receptor binds and phosphorylates the STAT, the STAT dissociates and translocates to the nucleus to do its thing. |
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Term
| cytokines stimulate and direct what 4 activities? |
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Definition
| cell division, differentiation, cell activation, and cell death |
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Term
| how do cytokines aggect hematopoiesis during an infection? |
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Definition
| during an infection, we need lots of neutrophils, so cytokines will affect differentiation of cells to promote a lot of neutrophiles and inhibit production of other cell types that we dont need |
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Term
| Can cytokines affect maturation of cells, differentiation of cells, or both? |
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Definition
|
|
Term
| how do cytokines affect T cells? |
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Definition
| the cytokines tell the native T cell to divide A LOT, and the cytokin environment affect which T-helper cells differentiate. The t cells then affect the cytokine environment for activating B cells and macrophages |
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Term
| The FAS and FASL signal typically ends in what? |
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Definition
| apoptosis through activation of caspases. |
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Term
| WHat is tissue necrosis factor? |
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Definition
| it is a signal that can either end in inflammation or apoptosis. |
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Term
| What class of enzymes transfers electrons, hydrogens, or hydride ions between moleceules? |
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Definition
| Oxidoreductases (sometimes called dehydrogenases) |
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|
Term
| What class of enzymes transfers a functional group? |
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Definition
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|
Term
| What class of enzymes cleave a C-O, C-N, or C-S bond by the addition of water across the bond? |
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Definition
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|
Term
| What class of enzymes add groups (usually water) to double bonds OR form double bonds (by the removal of water)? |
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Definition
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Term
| What class of enzymes transfers groups within a molecule to yield a differnt isomer? |
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Definition
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|
Term
| What class of enzymes forms a C-C, C-S, or C-N bond coupled with the cleavage of a high energy bond, such as ATP |
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Definition
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|
Term
| What is the main purpose of glycolysis? |
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Definition
| energy production in most of the body. In the liver, glycolysis makes acetyl CoA which can be used for synthesis of a lot different things including AA's, other sugars, cholesterol, fatty acids. |
|
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Term
| Breakdown aerobic glycolysis for me. |
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Definition
| glucose to pyruvate to acetyl-CoA. generates a net of 2 ATP's, 2 NADH, and 2 pyruvate. Net of 8 ATP (2 from glycolysis 3 per NADH from ETC) |
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Term
| breakdown anaerobic glycolysis for me. |
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Definition
| glucose to pyruvate to lactate, only 2 ATP yielded. 2 NADH's used in the conversion of pyruvate to lactate, but NAD+ is recycled. Net of 2 ATP |
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|
Term
| What is the first step of glycolysis? |
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Definition
| our glucose is phosphorylated at the 6th positon to form fructose-6-phosphate |
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Term
| What can we do with G6P, what paths can it take? |
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Definition
| can do glycolysis, the pentose phosphate pathway, glycogen synthesis |
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Term
| What is the first comitted step of glycolysis? |
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Definition
| When we add the 2nd phosphate to our 6 carbon molecule with phosphofructokinase and make fructose 1,6 biphosphate. |
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Term
| What does ATP do to phosphofructokinase's activity? What about AMP? citrate? fructose 2,6 biphosphate? |
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Definition
| ATP inhibits it (we don't need more energy). AMP reverses that inhibition aka activates it (we need energy). citrate is an allosteric inhibitor (we have a lot of energy). fructose 2,6 biphosphate is an allosteric activator ( we need energy) |
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Term
| Most kinase reactions usually require what two things? |
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Definition
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|
Term
| What enzyme breaks our 6 carbon molecule into 2 three carbon molecules in glycolysis? |
|
Definition
|
|
Term
| What converts DHAP to G3P? |
|
Definition
|
|
Term
| What does G3P dehydrogenase do? |
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Definition
| it catalyzes the oxidation of G3P from an aldehyde to an acid, and it phosphorylates it forming 1,3 bisphosphate glycerate (acid). this reaction also produces NADH. |
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|
Term
| What enzyme moves the phosphate group into the 2 position for dehydration? |
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Definition
| mutase (this is an isomerase) |
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|
Term
| What enzyme dehydrates 2-phosphoglycerate to form PhosphoEnolPyruvate (PEP)? |
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Definition
|
|
Term
| what converts PEP to pyruvate and produces an ATP in the process? |
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Definition
| Pyruvate Kinase. this is a good regulation point. |
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Term
| What conditions inhibit pyruvate kinase? what conditions stimulate it? |
|
Definition
inhibit: high ATP and high Acetyl-CoA
Stimulate: high AMP and high 1,6 biphosphoglucose, the product of the first committed step! |
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|
Term
| What drives glycolysis over the energy hill in the middle of the pathway? |
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Definition
| steps 4,5, and 6 should prevent it from continuing, however, inside the cell, it gets driven through because of the relative concentrations of products and reactants. We have a ton of reactants, which changes the physiologic delta G to a negative value and the reaction continues |
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|
Term
| What 3 places do we want to regulate a pathway? |
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Definition
| first committed steps, steps with large -delta G, and steps with different enzymes that are "one way" streets. |
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Term
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Definition
| it is when the RBC's get rid of their lactacte in the liver (or the heart) where it is resynthesized into glucose. this is expensive. costs 6 ATP for the liver to make 1 glucose that the RBC makes 2 ATP from |
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|
Term
| Where does glycolysis occur? what about the TCA cycle and the ETC? |
|
Definition
| glycolysis is in the cytoplasm, ETC and TCA are in the mitochondrion |
|
|
Term
| How does fructose 2,6 biphosphate affect glycolysis? gluconeogenesis? |
|
Definition
| it is an allosteric activator of glycolysis, and an allosteric inhibitor of gluconeogenesis |
|
|
Term
| how does fructose 1,6 affect glycolysis? |
|
Definition
|
|
Term
| How does fructose 2,6 biphosphate work in regulation of glycolysis? |
|
Definition
| it allosterically activates phosphofructokinase! |
|
|
Term
| what enzyme catalyzes the reaction of 3C pyruvate to 2C Acetyl CoA? |
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Definition
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|
Term
| In the liver, what happens during a fast and after a meal with regards to pyruvate kinase? |
|
Definition
fast: high glucagon inhibits PK, shifts metabolism towards gluconeogenesis over glycolysis.
meal: high insulin favors glycolysis over gluconeogenesis |
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|
Term
| What are the irreversible steps of glycolysis and gluconeogenesis? |
|
Definition
| Acetyl CoA cannot be converted to glucose, it must go thru TCA for glycolysis. Pyruvate cannot be rephosphorylated to PEP in gluconeogenesis, it has to go through a crazy mechanism to get there that involves oxaloacetate and GTP. |
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|
Term
| Pyruvate kinase is regulated in the liver how? |
|
Definition
| glucagon inhibits PK, favors gluconeogenesis. Insulin activates PK, favors glycolysis |
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|
Term
| What is the first step of gluconeogensis? |
|
Definition
| convert pyruvate to oxaloacetate. This requires ATP, CO2, and biotin. This step also replenishes the TCA cycle (OAA) |
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Term
| What factors regulate the 2nd regulatory point in glycolysis, the conversion of F6P to F16BP by PFK? |
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Definition
| F-2,6,-BP and AMP activate this step. ATP citrate and H+ inhibit this step |
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|
Term
| What factors regulate the 3rd regulatory point in glycolysis, the conversion of PEP to pyruvate by pyruvate kinase? |
|
Definition
| F,1,6BP activates this step, and ATP and alanine inhibit this step |
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Term
| What factors regulate the 1st regulatory point in gluconeogenesis, the conversion of pyruvate --> oxaloacetate --> PEP by pyruvate carboxylase and PEP carboxylase? |
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Definition
| Acetyl CoA activates the first step, and ADP inhibits both steps. |
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Term
| What factors regulate the 2nd regulatory point in gluconeogenesis, the conversion of F 16 BP to F6P by F16BP phosphatase? |
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Definition
| F 26 BP and AMP inhibit this step, and citrate activates this step. |
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|
Term
| Hormones regulate and coordinate __________ needs; alosteric regulation affects ______________ needs. |
|
Definition
| whole body; immediate intracellular |
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|
Term
| Acetyl Coa is formed by the activity of pyruvate dehydrogenase. What co-factors does this step use, and is it reversible? |
|
Definition
| CoASH, thiamine, and NAD+ are co-factors. this is an irreversible step, and is regulated. |
|
|
Term
| Glucagon phosphorylates Pyruvate dehydrogenase. does this activate or inhibit it? |
|
Definition
|
|
Term
| insulin dephosphorylates pyruvate dehydrogenase. does this activate or inhibit it? |
|
Definition
|
|
Term
| what molecules can be made into acetyl CoA? |
|
Definition
| the fatty acid palmitate, ketone body acetoacetate, pyruvate, and ethanol |
|
|
Term
| Acetyl CoA can be thought of as the first committed step in.... |
|
Definition
| lipid production (FA's, ketones, cholesterol) AND energy production. |
|
|
Term
| can acetyl CoA contribute to net glucose synthesis? |
|
Definition
| NO!! it can only go through TCA |
|
|
Term
| How many CO2 are formed during one TCA cycle? |
|
Definition
|
|
Term
| Break down the 1st half of the TCA cycle |
|
Definition
| Acetyl-CoA combines with OAA to form citrate. citrate gets rearranged and oxidatively decarbocylated twice to form Succinyl CoA. The CoA portion is then removed forming products of succinate and GTP. |
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|
Term
| oxidative decarboxylations require what vitamin as a cofactor? |
|
Definition
|
|
Term
| Where is the first NADH produced in the TCA cycle? |
|
Definition
| the second oxidative decarboxylation converting alpha ketogluterate to succinyl CoA |
|
|
Term
| breakdown the 2nd half of the TCA cycle. |
|
Definition
| succinate is oxidized to fumarate (C-C to C=C) producing an FADH. fumarate gets converted to malate. Malate is oxidized to OAA (C-OH to C=O) producing an NADH. |
|
|
Term
| how does ADP affect the enzymes in the TCA cycle? |
|
Definition
| it allosterically activates them. this makes sense because we need energy if we have a lot of ADP. |
|
|
Term
| What two compoudns would allosterically inhibit the TCA cycle? |
|
Definition
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