Lecture 01, 2

• What is the purpose of understanding major biosynthetic pathways?

  To understand their relationships and disorders
• How are biosynthetic pathways related to catabolic pathways?

  They are interconnected and influence each other
• What can disorders of biosynthetic pathways cause?

  Diseases
• What are free fatty acids carried around the body bound to?

  Albumin
• Why do free fatty acids bind to proteins in extracellular fluids?

  Due to low solubility in aqueous solution
• What is the primary use of free fatty acids?

  As a source of energy
• What are triglycerides also known as?

  Depot fats
• What components make up triglycerides?

  Fatty acids and glycerol
• Where are triglycerides stored in the body?

  Adipocytes
• What roles do phospholipids play in the body?

  In membranes and signalling pathways
• What are sterols used for in the body?

  In membranes and as hormone precursors
• What is the major component of the myelin sheath?

  Sphingomyelin
• What are the two types of phospholipids mentioned?

  Phosphoglycerides and sphingomyelin
• What is the core structure of phospholipids?

  Same core structure with different alcohol groups
• Where does phospholipid synthesis take place?

  On the endoplasmic reticulum
• What is the first step in phospholipid synthesis?

  Formation of phosphatidate
• What is required for the activation step in phospholipid synthesis?

  Cytidine triphosphate (CTP)
• What enzyme is involved in the formation of a phosphatide?

  Glycerol phosphate acyl transferase
• What is produced during the formation of a phosphatide?

  Diacylglycerol-3-phosphate
• What drives the activation of diacylglycerol?

  Hydrolysis of pyrophosphate
• What happens during the addition of alcohol in phospholipid synthesis?

  Alcohol is activated by ATP and CMP
• What is the most common phospholipid?

  Phosphatidylcholine (PC)
• How is phosphatidylserine (PS) synthesised?

  From PC or PE by base exchange
• What is the role of phosphatidylserine in the body?

  Important in apoptosis and cell signalling
• Where are sphingolipids found in the body?

  Highest concentration in the CNS
• What is the first step in sphingolipid synthesis?

  Formation of ceramide intermediate
• What is the enzyme involved in the condensation step of ceramide formation?

  Serine palmitoyl transferase
• What cofactor is required for the condensation step in ceramide formation?

  Pyridoxal phosphate (vitamin B6)
• What is generated during the oxidation step of ceramide formation?

  FADH2

  
• What are glycolipids?

  Sphingolipids containing sugars
• What are the four types of glycolipids?

  Cerebrosides, sulphatides, globosides, gangliosides
• What is the significance of gangliosides?

  Important in oncogenesis
• What is dipalmitoyl phosphatidylcholine (DPPC) used for?

  To lower surface tension in alveoli
• What happens if there is insufficient synthesis of DPPC?

  Leads to respiratory distress syndrome
• What is the lecithin-sphingomyelin ratio used to assess?

  The potential for respiratory distress syndrome
• What treatment is given to mothers to accelerate fetal lung maturation?

  Glucocorticoids
• What genetic mutation causes Tay-Sachs Disease?

  Affects β-N-acetylhexosamidase
• What is the consequence of Tay-Sachs Disease?

  Build-up of gangliosides in the brain
• What is the result of the build-up of gangliosides in Tay-Sachs Disease?

  Weakness, dementia, and eventual death
• What is the structure of free fatty acids?

  Long hydrocarbon chain with an acid group