Bio2

• Carbohydrates

  Organic compounds made up of carbon, hydrogen, and oxygen
• Carbohydrates


  • Primary source of energy for cellular metabolism
  • Can be classified as simple (monosaccharides) or complex (polysaccharides)
• Monosaccharides

  • 3 to 6 carbon atoms
  • Contain carbonyl and hydroxyl functional groups
  • Can be classified as aldoses or ketoses
• Reducing sugars

  Sugars that can reduce other substances, certain metal ions, due to the presence of aldehyde or ketone group
• Monosaccharides

  • D-glucose
  • D-fructose
  • D-galactose
• Cyclic formation of sugar molecules

  1. Formed through reaction between carbonyl and hydroxyl on another carbon within same molecule

  2. Forming hemiacetal or hemiketal linkage

  3. Cyclization
• Disaccharides

  Formed when 2 monosaccharides are joined by condensation, can be hydrolysed to form monosaccharides
• Disaccharides

  • Maltose
  • Sucrose
  • Lactose
• Polysaccharides


  Many simple sugar molecules bonded together in long chains
• Polysaccharides


  • Starch
  • Glycogen
  • Cellulose
  • Chitin
• Starch

  • Stored in plants, composed of amylose (linear) and amylopectin (branched)
  • Amylose is more resistant to digestion, providing sustained release of glucose
• Glycogen


  • Stored in animals, especially in liver and muscle
  • Branched polymer of glucose
• Cellulose


  • Main structural carbohydrate in plants, linear polymer of glucose with β-1,4-glycosidic bonds
  • Resistant to enzymatic degradation
• Dietary fiber

  Naturally found in plant-based foods, can be soluble (e.g. pectins, gums) or insoluble (e.g. cellulose, lignin)
• Health effects of dietary fiber

  • Bind to cholesterol, reduce risk of heart disease and diabetes
  • Trap carbohydrates to slow down digestion and absorption
  • Increase fecal weight and prevent constipation, diverticulosis and hemorrhoids
• Lipids are biomolecules that contain steroids and fatty acids, are insoluble in water but soluble in organic solvents
• Types of lipids

  • Simple lipids (fats, oils, waxes)
  • Compound lipids (phospholipids, glycolipids)
  • Derived lipids (fatty acids, steroids, fat-soluble vitamins)
• Triglycerides

  Simple lipids composed of 3 fatty acid chains bound to a glycerol backbone
• Phospholipids

  Compound lipids with 2 fatty acids, 2 glycerols, and 1 phosphate group, are amphipathic
• Saturated fatty acids


  Fatty acids with single carbon-carbon bonds, straight chain, solid at room temperature
• Unsaturated fatty acids


  Fatty acids with one or more carbon-carbon double bonds, kinked shape, liquid at room temperature
• Saturated fatty acids

  May raise LDL cholesterol and increase risk of heart disease
• Unsaturated fatty acids

  May help lower LDL cholesterol and reduce risk of heart disease
• Hydrogenation


  Process that converts liquid vegetable oils into solid or semi-solid fats
• Room Temperature

  - Saturated Fatty Acid : solid

  - Unsaturated Fatty Acid : liquid
• Saturated Fatty Acids

  Straight-chain hydrocarbons with single bonds between carbon atoms, Solid
• Unsaturated Fatty Acids


  Contain one or more double bonds between carbon atoms, resulting in tightly packed kinks or bends in the chain, Liquid
• Saturated Fatty Acids

  • Found in animal products like meat, butter, and cheese, May raise LDL cholesterol blood levels and increase the risk of heart disease
• Unsaturated Fatty Acids

  • Found in plant oils like olive oil, canola oil, and avocado oil, as well as in nuts, seeds, and fish, May help lower LDL cholesterol levels and reduce the risk of heart disease
• Hydrogenation


  Converts liquid vegetable oils into solid or semi-solid fats
• 1. C


  Single bond between carbon atoms
• C=C

  Double bond between carbon atoms
• Saturated Fats

  • Long-straight chain, Solid at room temperature
• Unsaturated Fats

  • Kinks made by C=C prevent packed tightly, Liquid at room temperature
• Steroids

  Four interconnected rings of carbon atoms, Functions to regulate metabolism, immune response, inflammation, reproduction
• Cholesterol

  Waxy, fat-like substance found in all cells of the body, Synthesised by the liver or gained from dietary sources, Essential for formation of cell membranes, synthesis of hormones, and production of bile acids
• Importance of Fatty Acids

  • Inflammation
  • Brain Function
  • Cardiovascular Health
• Essential Fatty Acids


  Cannot be made by the body, Essential for reducing inflammation, Crucial for brain health and function, Essential for heart health
• Non-Essential Fatty Acids


  Made by the body, Excessive intake can promote inflammation, Not crucial for brain function, Can impact heart health, but not essential
• Protein Synthesis

  Condensation of chain of amino acids (CHON), Sequence determined by DNA, Peptide bond formed when carboxyl group (COOH) combines with amine group of 2 different amino acids, Release of water