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36 Cards in this Set
- Front
- Back
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How are fatty acids named?
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# of carbons : # of double bonds delta (location of double bond)
e.g. 18:2 delta 9,12 18 carbons with two double bonds at 9 and 12 |
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What is the role of bile acids in fatty acid metabolism?
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Bile acids break emulsify dietary TGs
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Where does the fatty acid beta oxidation occur?
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Mitochondrial matrix
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What is the significance of the carnitine shuttle?
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beta oxidation of fatty acids needs to occur in the mitochondrial matrix, which is impermeable to TGs.
The carnitine shuttle transports TGs into the matrix in order for beta oxidation to occur. |
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What are the reactions of beta oxidation?
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1. dehydrogenation (generates FADH2)
2. hydration 3. oxidation (generates NADH) 4. thiolysis |
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How much ATP does each course (per Fatty Acyl Coa) of beta oxidation generate?
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17 ATPs
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What enzyme in beta oxidation produces FADH2?
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Acyl coA dehydrogenase
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What enzyme in beta oxidation produces NADH?
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3-hydroxylacyl CoA dehydrogenase
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What enzymes are needed to metabolize unsaturated fatty acids?
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an isomerase: enoyl CoA isomerase
a reductase: (for polyunsaturated fatty acids) 2,4-dienoyl CoA reductase |
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Describe the role of the end products of fatty acid oxidation
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Acetyl coA can be funneled into ketogenesis during fasting sate
Propinoyl CoA will go through three more steps to form Succinyl CoA (an glycoloysis intermediate), which can also form malate and go into gluconeogenesis |
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What is the role of ketone bodies in metabolism?
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During fasting, fatty acids are broken down into ketone bodies, which are a major source of fuel in this state.
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What tissues use ketone bodies for fuel?
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skeletal muscles, brain, kidneys, instestinal muscosa
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How is the rate of ketone body formation regulated?
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by the rate of beta oxidation
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What steps of propionyl CoA metabolism require cofactors and which ones?
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First step with Propionyl CoA carboxylase requires Biotin
Third step with methylmanonylCoa Mutase requires B12 |
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What complex is needed for actetyl coA carboxylase?
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biotin, CO2, ATP
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Where are triglycerides produced?
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liver, muscle, adipose tissue
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What delivers cholesterol to tissues?
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LDL
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What carries triglycerides to peripheral tissues?
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VLDL
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How many NADPHs are used per acetyl CoA during fatty acid synthesis?
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2 NADPHs per acetyl CoA
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From which two substances are phospholipids made?
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diacylglycerols and phosphatidic acid
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What is needed to desaturate a site on a fatty acid?
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NADH, O2 and cytochrome b5
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What is released at the end of each round of beta oxidation?
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acetyl Coa, FADH, and NADH
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Which enzyme hydrolizes triacylglycerols into free fatty acids and glycerol?
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hormone sensitive lipase
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What regulates the rate of ketone body formation?
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the rate of beta oxidation
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What intermediate allows propionyl CoA to enter into the TCA cycle?
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succinyl CoA
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What are the three ketone bodies?
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acetoacetate, acetone and beta-hydroxybutyrate
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What are the important steps involved with the Fatty Acid Synthase complex?
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It is a large homodimer
2 reduction reactions, requiring NADPH Each subunit has7 catalytic activities The Acyl carrier protein segment has a phosphopantheine residue |
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What cofactors are required for fatty acid desaturation?
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molecular oxygen, NADPH and cytochrome b
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What amino acids are ketogenic?
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lysine
leucine isoleucine trypptophan phenylalanine Tyrosine |
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What three enzyme systems primarily participate in the fatty acid synthesis?
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fatty acid synthase
fatty acid elongase fatty acid desaturas |
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Where in the cell does elongation and desaturation of fatty acids occur?
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both occur in the endoplasmic reticulum
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Where are triacylglycerols produced?
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the smooth ER of the liver
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What processes require MTPs for assembly?
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VLDL and chylomicron assembly
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What role does lipoprotein lipase play in forming fatty acids?
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cleaves the triacylglycerols in VLDL (and chylomicrons) to form fatty acids and glycerol
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How does the insulin/glucagon ratio affect fatty acid synthesis?
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Lipoprotein lipase is secreted by adipose cells when the insulin/glucagon ratio is high (fed state) and fatty acids enter adipose cells to form TAGs
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A patient presents with vomiting, convlusions and coma after eating an akee fruit. What went wrong?
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Akee fruit contains Hypoglycin A, which inhibits acyl CoA dehydrogenase. Leads to fasting hypoglycemia. Severely affects people with low levels of acyl CoA DH.
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