lipids lecture

• What is the fourth major group of molecules found in all cells?

  Lipids
• How do lipids differ from nucleic acids, proteins, and polysaccharides?

  They are not polymeric
• What is a common feature of lipids?

  Insolubility in water
• What are the three biological functions of lipids?

  • Components of biological membranes
  • Energy storage
  • Intra- and intercellular signaling

  
• How do lipids compare to proteins and carbohydrates in terms of energy?

  They provide more energy
• What are the applications of lipids in various industries?

  • Cosmetic industry
  • Food industry
  • Nanotechnology

  
• What type of molecules are lipids?

  Hydrophobic, nonpolar molecules

  
• In what type of solvents are lipids soluble?

  Nonpolar solvents
• How are lipids isolated from other biological molecules?

  By extracting them with nonpolar solvents
• What are the primary functions of different lipid categories?

  • Fatty Acids: Energy storage, signaling precursors
  • Waxes: Waterproofing, protection, lubrication
  • Triacylglycerols: Energy storage, insulation, cushioning
  • Phospholipids: Membrane structure, cell signaling
  • Glycolipids: Cell recognition, communication
  • Steroids: Membrane stability, hormonal regulation
  • Prostaglandins: Inflammation mediation, immune regulation
  • Lipophilic Vitamins: Vision, bone health, antioxidant activity
  • Terpenes: Precursors for vitamins, signaling, protection
• What are fatty acids?

  Carboxylic acids with hydrocarbon chains
• What distinguishes saturated fatty acids from unsaturated fatty acids?

  Saturated have no double bonds
• What state are saturated fatty acids at room temperature?

  Solids
• What state are unsaturated fatty acids at room temperature?

  Liquids
• What is the structure of fatty acids?

  Long-chain unbranched carbon with a carboxyl group

  
• How many carbon atoms do fatty acids typically have?

  12 to 20 carbon atoms

  
• What is the solubility of fatty acids in water?

  Insoluble
• What makes fatty acids nonpolar despite having a polar group?

  The long hydrocarbon tail
• What is the melting point of saturated fatty acids?

  Higher than unsaturated fatty acids

  
• What are essential fatty acids?

  Fatty acids that must be obtained from diet
• What is the significance of omega-3 fatty acids?

  They prevent heart diseases
• What are the three main omega-3 fatty acids?

  ALA, EPA, DHA
• What are the functions of omega-3 fatty acids?

  Anti-inflammatory and cardiovascular health
• What are omega-6 fatty acids essential for?

  Skin health and cell membrane integrity
• What is the ideal omega-6:omega-3 ratio?

  2:1 to 4:1
• What are trans fatty acids associated with?

  Health risks
• What are the properties and functions of waxes?

  • Highly hydrophobic
  • Excellent barriers against water
  • Found in plants, animals, microorganisms
  • Functions: protective, structural, energy storage
• What is the structure of waxes?

  • Long-chain fatty acid (14-30 carbons)
  • Long-chain alcohol (16-30 carbons)
  • Linked by ester bond (-COO-)

  
• What are the sources and functions of waxes in plants?

  • Found on surfaces of leaves, stems, fruits
  • Prevent water loss
  • Protect against environmental damage
• What are the sources and functions of waxes in animals?

  • Found in secretions (e.g., beeswax, lanolin)
  • Water-repellent coatings
  • Protect skin and hair
• What are the properties of triglycerides?

  • Storage form of fatty acids
  • High triglyceride levels indicate atherosclerosis risk
• What is the structure of triglycerides?

  Three fatty acids attached to glycerol

  
• What happens to triglycerides made from unsaturated fatty acids?

  They have lower melting points

  
• What is the relationship between triglycerides from animals and saturation?

  They tend to have higher saturation
• What is the primary component of triglycerides?

  Three fatty acid molecules and glycerol

  
• What is glycerol also known as?

  Glycerin
• How do fatty acids react with glycerol?

  They form esters through hydroxyl groups

  
• How many esters can be formed from one glycerol molecule?

  Three esters
• What happens to the hydroxyl groups in triglycerides?

  All three are attached to fatty acid residues

  
• What effect do cis double bonds have on melting points of triglycerides?

  They lower the melting points