Fatty acid Metabolism S2M2

  1. What are chemically classified as unsaturated acids but act like saturated fatty acids
    Trans Fatty Acids
  2. What are the essential fatty acids and which are the semi-essential
    • Essential - Linoleic acid & alpha Linolenic acid
    • Semi-essential - Arachidonic acid
  3. Why is Arachidonic acid considered a semi-essential fatty acid
    It becomes an essential fatty acid if linoleic acid is absent in a diet
  4. Arachidonic acid is the precursur for
    • Ecosanoids
    • - Thromboxane (TXA2)
    • - Prostaglandins/Prostacyclins (PGH2)
    • - Leukotrienes
  5. Arachidonic acid is broken down to Leukotrienes via
  6. Arachidonic acid is broken down to Thromboxane and Prostaglandins via
    Cyclooxygenase (COX-1 or 2)
  7. What is the difference between COX-1 and 2
    • COX-1 is found in most tissues
    • COX-2 is found in WBC and other associated immune response elements
  8. Eicosapentaenoic acid (Omega 3 from fish oil) can be broken down into
    Thromboxanes and Prostaglandins through Cyclooxygenase
  9. How does TXA3 compare to TXA2
    2 is a more potent activator of platelet aggregation
  10. Why is fish oil a recommended source for patients with chronic heart disease
    It is used to make TXA3 instead of TXA2 which is a greater activator of platelet aggregation
  11. What are some key symptoms of Fatty Acid deficiency
    • Scaly dermatitis
    • Hair loss
    • Poor wound healing
    • Infertility
  12. What is the role of Lipoprotein lipase in the muscle
    It removes Fatty acids for Beta Oxidation
  13. Where is Lipoprotein lipase not made
    In the liver or brain
  14. What happens to Lipoprotein lipase in the fed state
    • Synthesis in the Adipocytes goes up
    • Synthesis in the Skeletal and heart muscle goes down
  15. What happens to Lipoprotein lipase in the fasting state
    • Synthesis and activity in the Adipocytes goes down
    • Synthesis and activity in the muscle goes up
  16. Lipoprotein lipase levels are always high when
    Lactating (active mammary gland)
  17. 90% of adipose tissue is made of
  18. How do Carbohydrates and their energy potential compare to Beta Oxidation
    Beta Oxidation yields more energy
  19. What are the substrates made in the process of synthesizing Triacylglycerol
    • Dihydroxyacetone phosphate (Adipose/Liver)
    • Glycerol 3 Phosphate
    • Phosphatidate
    • Lysophosphatidate
    • Diacylglycerol
    • Triacylglycerol
  20. What is the effect of insulin release on adipose tissue
    It stimulates the synthesis of triglycerides and Lipoprotein lipase in adipose tissue
  21. What hormones act through cAMP and Protein Kinase A
    • Norepi/ Epi
    • Glucogon
    • ACTH
    • Melanocyte stimulating hormone (MSH)
    • TSH
  22. Which hormones stimulate protein synthesis
    • Thyroid Hormones
    • Growth Hormones
    • Glucocorticoids
    • (Insulin Inactivates)
  23. What would be the result on muscles if there was a failure to oxidize fatty acids
    They would be fatigued
  24. Medium and long chain fatty acids require what for transport across the inner mitochondrial membrane
  25. 97% of small amino acids are found where
  26. How do fatty acids get into the mitochondria of muscle cells
    • 1 - FA binds to carnitine forming Acyl-Carnitine by way of CPT1
    • 2 - Acyl-Carnitine travels through first membrane
    • 3 - Translocase delivers Acyl-Carnitine to the matrix
    • 4 - CPT2 seperates Acyl-CoA from Carnitine in mito
    • 5 - FA is released from carnitine for Oxidation
    • Carnitine returns to cytosol through translocase
  27. What is the rate limiting step for Fatty acids entering the mitochonria matrix
  28. Acyl-CoA dehydrogenase
    Enzyme that catalyses the initial step of fatty acid beta Oxidation in the mitochondria
  29. In order for monosaturated fatty acids to undergo beta oxidation, what must happen
    3, 2- enoyl CoA isomerase must be present to convert Cis bonds to trans configuration
  30. What must be present for Polyunsaturated fatty acids to undergo beta oxidation
    NADPH dependent 2,4-dienoyl CoA reductase as well as an isomerase
  31. Beta oxidation is
    • The process by which fatty acids, in the form of Acyl-CoA molecules, are broken down in mitochondria and/or in peroxisomes to generate
    • Acetyl-CoA, the entry molecule for the Citric Acid cycle
  32. What takes place with Very Long Chain Fatty Acids (VLCFA) in peroxisomes for them to undergo beta oxidation
    • VLCFA are converted to octanoyl-CoA (8 carbon fatty acid)
    • Octanoyl-CoA leave peroxisomes
    • Octanoyl-CoA then pass through Mitochondria via carnitine
    • Beta Oxidation takes place
  33. How does the product of beta oxidation of VLCFA compare to medium chain fatty acids
    Medium provide more energy
  34. Zellweger Syndrome
    • Defect in peroxisome biogenesis effecting all tissues
    • Effects neural positioning and brain development
  35. Adrenleukodystrophy
    • X- linked
    • Effects VLCFA from crossing peroxisome membranes
    • Accumulation of VLCFA in blood and tissues leading to abnormalities in the white matter of the cerebrum
  36. What is the energy yield of one molecule of Palmitoyl CoA
    131 ATP
  37. Phytanic acid
    Fatty acid obtained through eating dairy products, animal fats, and certain fish
  38. Refsums disease
    • Accumulation of Phytanic acid
    • Neurological disorder
    • Dietary restriction of green vegetables, milk, and meat
  39. What is the result of a lack of alpha-hydroxylase
    • Phytanic acid can't be broken down to acetyl CoA
    • "Refsums disease"
  40. Odd chain fatty acids like Propionyl-CoA require what for its breakdown
    • Biotin
    • Vit B12
  41. Propionyl
    • Product of beta Oxidation of odd chain fatty acids
    • It is further broken down to Succinyl-CoA
  42. Methylmalonyl aciduria
    • Defective methylmalonyl-CoA mutase used to break down odd chain fatty acids to Succinyl CoA
    • Deficiency in B12 can cause it
  43. Propionyl-CoA carboxylase is dependent on
    Biotin for the breakdown of Propionyl CoA to Methylmalonyl-CoA eventually forming Succinyl-CoA
  44. Malonyl-CoA
    Formed in the synthesis of fatty acids
  45. What controls beta Oxidation
    • Malonyl-CoA inhibits it by stopping fatty acids from forming with carnitine
    • A low availability of fatty acids inhibits beta oxidation
  46. The formation of Ketone bodies is effected by
    • Insulin inhibits
    • Glucogon promotes
    • Epinephrine promotes
  47. What happens to the products of beta oxidation that exceeds the intake of the TCA cycle
    It is turned into ketone bodies
  48. Why in the starvation state are ketones used highly in the brain for energy
    This is so RBCs can use whatever glucose in left
  49. The body attempts to limit degradation of muscle in the starvation state by
    Using fatty acid and Ketone bodies for energy
  50. Linoleic acid is a precusur for
    Arachidonic acid
  51. What are the compounds categorized as ketone bodies
    • Acetoacetate
    • Beta-hydroxybutyrate
    • Acetone
  52. In the fasting state how do the levels of Acetoacetate and Beta-Hydroxybutyrate compare
    • They both rise but Beta-hydroxybutyrate is almost six times as high as Acetoacetate
    • Acetoacetate levels are close to those of free fatty acids
  53. What causes Ketoacidosis from the Ketone bodies
    COO- group of the ketone bodies has a pka of about 4, while circulating through the plasma they loose their H+
  54. What can cause medium chain acyl-CoA dehydrogenase deficiency
    • Akee fruit
    • Individuals with a copy of the MCAD allele
  55. What organs use ketones as fuel in the fasting state
    • Muscle
    • Heart
    • Kidneys
    • Brain in severe circumstances
  56. What is the effect of medium chain acyl-CoA dehydrogenase deficiency
    • Decreased ability to use fatty acids as fuel
    • High levels of fatty acids in plasma
    • Fat accumulation in the liver
  57. What is the effect of Caritine deficiency
    • Slowed transfer rate of long chain fatty acids
    • Increase fatty acids in the blood
    • Hypoglycemia
    • Muscle weakness
    • Impaired gluconeogenesis
  58. Acetyl CoA carboxylase requires what to be active
    ATP and Biotin
  59. Acetyl CoA carboxylase is used for
    • Breaking down acetyl CoA bicarbonate to Malonyl CoA
    • It is the rate limiting step of fatty acid synthesis
  60. Acetyl CoA carboxylase is regulated by
    • Citrate allosterically activates
    • Insulin activates
    • Palmoitoyl-CoA allosterically inhibits
    • Glucagon inhibits
    • Epinephrine inhibits
Card Set
Fatty acid Metabolism S2M2