Lipids Flashcards
Generally compartmentalized to protect themselves from watery environment of cells
Transported in blood by lipoproteins
Lipids
Long chains of carboxylic acids
Fatty acids
FA: Predominant in coconut oil
Lauric Acid
End product of mammalian FA synthesis
Palmitic Acid
Predominant FA in olive oil
Oleic acid
Essential Fatty Acids
Linoleic acid
Linolenic acid
Precursor of prostaglandins, derived from linoleic acid
Arachidonic acid
Synthesis of fatty acids, specifically, palmitate
Lipogenesis
Where does Lipogenesis occur?
Liver
Immediate substrate of Lipogenesis
Acetyl CoA
Product of Lipogenesis
Palmitoyl CoA
Rate limiting step of Lipogenesis
Acetyl CoA carboxylase
Transport of Acetyl CoA to the Cytosol via
Citrate Shuttle
Identify the enzyme: Acetyl CoA is converted to Malonyl CoA
Acetyl CoA carboxylase
The rate limiting step of lipogenesis is activated by
Citrate
Insulin
The rate limiting step of lipogenesis is inhibited by
Glucagon
Epinephrine
Fatty acids are stored as
Triacylglycerol
Sources of Glycerol-3-Phosphate
DHAP from glycolysis
Phosphorylation of free glycerol
Identify the enzyme: DHAP from glycolysis
Glycerol 3 phosphate dehydrogenase (liver and muscle)
Identify the enzyme: Phosphorylation of free glycerol
Glycerol kinase (liver only)
Identify the enzyme: Triacylglycerol -> Glycerol + 3 Fatty Acids
Hormone sensitive lipase
Removal of Acetyl CoA fragments from the ends of fatty acids, also yielding NADH and FADH2 in the process
Beta-Oxidation
Substrate of Beta-Oxidation
Palmitate
Products of Beta-Oxidation
8 Acetyl CoA
7 NADH
7 FADH2
Rate limiting step of Beta-Oxidation
Carnitine-Palmitoyl transferase
Sequence of Elongation to Palmitoyl CoA
Condensation
Reduction
Dehydration
Reduction
Sequence of Degradation of Fatty Acyl CoA
Oxidation
Hydration
Oxidation
Thiolysis
Propionyl CoA carboxylase requires
Biotin
Methylmalonyl CoA mutase requires
Vitamin B12
____________ oxidize very long chains of fatty acids
Peroxisomes
Steatorrhea
Lipid Malabsorption
Results in deficiency in fat soluble vitamins and essential fatty acids
Lipid Malabsorption
Ichthyosis (Scaly dermatitis)
Hair loss
Poor wound healing
Deficiency of Essential Fatty Acids
Inadequate synthesis or renal loss of carnitine
Carnitine deficiency
Clinical presentation of Carnitine deficiency
Hypoglycemia - impaired fatty acid oxidation
Lipid accumulation with muscular weakness
Treatment of Carnitine deficiency
Oral supplementation with carnitine
Due to reduced fatty acid oxidation, leading to severe hypoglycemia, coma, and even death
Affects the LIVER
Carnitine-Palmitoyl Transferase I deficiency
Cardiomyopathy
Muscle weakness with myoglobinemia after prolonged exercise
Affects CARDIAC and SKELETAL MUSCLE
Carnitine-Palmitoyl Transferase II deficiency
Most common inborn error of fatty acid oxidation
Medium-Chain Fatty Acyl CoA Dehydrogenase (MCAD)
Severe hypoglycemia
Accumulation of fatty acids in the urine
Can manifest Sudden Infant Death Syndrome
Medium-Chain Fatty Acyl CoA Dehydrogenase Deficiency (MCAD)
Treatment of MCAD
IV glucose during acute episodes
Avoidance of fasting
Caused by eating the unripe fruit of the akee tree
Jamaican Vomiting Sickness
Deficiency of Phytanoyl-CoA hydroxylase
Accumulation of Phytanic Acid
Refsum Disease
Clinical presentation of Refsum Disease
Peripheral neuropathy and ataxia
Retinitis pigmentosa
Abnormalities of the skin and bones