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22 Cards in this Set
- Front
- Back
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What are the actions of CCK?
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Decrease GI motility
Signal pancreas to release lipase Signal gallbladder to release bile |
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What is the role of secretin?
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Signal pancreas to release bicarbonate
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What is the action of glucagon and epinephrine on adipose (starved)?
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Bind to receptor
Stimulate G protein which signals Adenylate Cyclase cAMP results which sends a signal to PKA PKA phosphorylates Lipase Breaks down Triacylglycerols to FA and Glycerol |
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Activation of LCFA - Beta oxidaiton of FA
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Occurs in the cytosol
Thiokinase detatches 2 Pi from ATP Attaches FA to AMP Thiokinase then exchanges AMP for CoA resulting in LCFA-CoA which is highly reactive (-SH) |
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Transport of LCFA into mitochondria - Carnitine Shuttle
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Reuires Carnitine for translocation
Start and End with LCFA-CoA FA-CoA has to be changed b/c its to big FA-CoA + Carnitine = FA-Carnitine + CoA-SH catalyzed by CAT 1 Now can be transported In side the rxn is reversed by CAT 2 |
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Inhibitor of Carnitine Shuttle
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Malonyl CoA
Intermediate in FA synthesis Ihibits CAT 1 or CPT 1 Ensures Beta Oxidation is inhibited while synthesis is occuring |
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Sources of Carnitine
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Meat
Synthesized from lysine and methionine in liver and kidney NOT muscle |
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Do SCFA and MCFA need the carnitine shuttle?
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No they can cross the mitochondrial membrane w/o it.
Once inside they are activated to their Coenzyme A derivatives |
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Mitochondrial B-Oxidation of FA
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Occurs at Beta Carbon with Cleavage between the Alpha and Beta
Forms Acetyl CoA & FA-CoA that is 2 carbons shorter Acetyl CoA is then used in TCA or to make KB Each round produces 1 NADH and 1 FADH2 |
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B-Oxidation of Saturated fatt acyl CoA containng an ODD number of Carbon
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Produce Acetyl CoA's and Propionyl CoA
Propionyl-CoA is then converted to Succinyl CoA where it can enter the TCA for further oxidation |
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The steps of the B-oxidation of fatty acyl CoA containing Odd #
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Propinoyl CoA goes under a carboxylase rxn requirein BIOTIN
Then undergoes a Epimease Rxn which rearanges the molecules Then a MUTASE Rxn changes into Succinyl CoA requires B12 |
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B-Oxiation of MUFA and PUFA
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Same rxn happens excepts when a double bond is encoutered then step 1 is skiped b/c you already have a double bond
The double bond isomerized by Enoyl-CoA and Oxidation continues |
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B-Oxidation of Very long FA
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Undergo a preliminary B-Oxidation in peroxisomes
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Zellweger Syndrome
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Genetic defect in Peroxisomal biogenis in all tissues
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Refsum Disease
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Defiency in A-hydroxylase
Results in a build up of Phytanic Acid |
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Overview of LCFA B-Oxidation
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Step 1: FA activated by ATP to make Fatty Acyl Adenylate CoA-SH comes in and makes Fatty Acyl-CoA
Step 2: Carnitine comes in a makes Fatty Acyl Carnitine so it can pass through membrane with Step 3: With help from CAT/CPT I & II passes into Matrix Step 4: CoA-SH replaces Carnitine to again make Fatty Acyl CoA Fatty Acyl-CoA then goes through 4 rxns of B-Oxidation which repeats until all RA made into Acetyl CoA (TCA) Each round 1 NADH, FADH2 |
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Defieiencies in Carnitine Pathway
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Cant bring the Fatty Acyl-CoA from cytosol to matrix
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Carnitine Palmitoyltransferases Deficiency
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CPT I: Affects liver, reduced FA Ox and ketogenesis
CPT II: Recurent muscle pain and fatigue from streneous activity |
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Deficiencies in Acyl-CoA Dehydronenases
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Inherited diseases tjat impair B-Oxidation
Affects VLCAD, LCAD, MCAD, SCAD MCAD is the most common become apperent in firt years followed by fasting Excessive urinary w/MCAD is diagnostic |
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Lipid Malabosorbtion
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Excess loss of lipids
For Causes 1. defect liver does NOT make bile 2. Obstruction of bile duct 3. Obstruction in Pancreatic Duct 4. Damage/defect in the intestinal mucosal cells Pts. should avoid LCFA , High amts. of CHO and Protein |
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Sphingolipidoes
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Important in CNS covering nerves, etc.
Is a lysomal disease |
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Gauchers Disease
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Most common sphingolipid disease
Accumlation of enlarged macrophages Enlarged Spleen & Liver Degradation of RBC Progressive brain damage (TYPE II & III) Mutation in GBA gene causes it |
