Lipids and carbohydrates

• Macromolecules


  Large molecules formed from monomers
• Types of macromolecules


  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids
• Formation of macromolecules


  1. Condensation reactions

  2. Water is removed
• Breaking down macromolecules


  Hydrolysis - in the presence of water
• Glycosidic bond


  Bond between sugars
• Hexose sugars


  • Alpha glucose
  • Beta glucose
• Alpha glucose


  • H on top of C1
• Beta glucose


  • H on bottom of C1
• Carbon 1


  First carbon clockwise from the oxygen
• Pentose sugars


  • Ribose
  • Deoxyribose
• Carbon


  • Building blocks of life
  • Found in carbs, proteins, nucleic acids
  • C-C bonds are stable
  • Forms 4 covalent bonds
  • Can be single rings (glucose) or multiple rings (cholesterol)
  • Can be branched (triglycerides) or unbranched (fatty acids)
• Monomer->polymer->macromolecule


  1. Glucose->polysaccharide->amlose+amylopectin in starch + cellulose

  2. Amino acid->polypeptide->proteins

  3. Nucleotide->polynucleotide->DNA + RNA

  4. Fatty acids + glycerol -> triglyceride -> fats + oils
• Glucose


  • Soluble in water (polar)
  • Transportability
  • Energy yield
  • Chemical stability
  • Can be oxidized
• Monosaccharides


  • Glucose
  • Fructose
  • Deoxyribose
  • Ribose
• Disaccharides


  • Sucrose
  • Maltose
  • Lactose
• Polysaccharides


  • Starch
  • Glycogen
  • Cellulose
  • Chitin
• Starch


  • Alpha glucose
  • Amylose (1,4) and amylopectin (1,4 and 1,6)
  • 1,6 is for branches
• Glycogen


  • Alpha glucose
  • 1,4 and 1,6
• Cellulose


  • Beta glucose
  • Forms microfilaments
  • 1,4
• Glycoproteins


  • Proteins and carbohydrates in cell membrane
  • Cell-cell adhesion and comms
  • Receptors
  • Immune response
  • Structural support - forms part of the extracellular matrix
  • Acts as antigens if not recognized
• Blood groups


  • A - antigen A present, B antibodies
  • B - antigen B present, A antibodies
  • AB - A and B present, no antibodies, universal recipient
  • O - no antigens, A and B antibodies, universal doner
• Role of hydrolysis between mono di and polysaccharides

  1. Hydrolysis -> break down in the presence of water

  2. Poly->di->monosaccharide

  3. Many sugars->2 sugars->1 sugar

  4. Split into fragments->split into 2

  5. OH and H are added
• Difference between cellulose and glycogen

  • Cellulose has beta glucose, glycogen has alpha glucose
  • Glycogen is branched, cellulose is not
  • Glycogen has 1,4 and 1,6, cellulose only has 1,4 glycosidic bonds
  • Cellulose is used in plant cell walls and is very hard, glycogen is the energy store for animals, is high in energy
  • Glycogen is compact, cellulose is a straight chain
  • Cellulose bundles are stable, high tensile strength
  • Easy to add/subtract unit from a glycogen molecule
• Lipids


  • Hydrophobic, insoluble in aqueous solutions
  • Dissolves in non-polar solvents
• Triglycerides


  • 1 fatty acid
  • 3 glycerol
• Triglyceride synthesis


  Glycerol + 3 fatty acids --(condensation)--> triglyceride + 3 water
• Fats


  Saturated triglycerides, solid at room temp due to being saturated
• Oils


  Unsaturated triglycerides, liquid at room temp
• Cis-isomers


  • At the C=C bond, the attached H atoms are on the same side
  • Causes a kink in the fatty acid chain
  • Less tightly packed
  • Liquid at room temp
• Trans-isomers


  • The attached H atoms are on opposite sides
  • No bend, tightly packed, higher melting point
  • Solid at room temp
• Energy storage in plants

  • Lipids stored in seeds
  • Mostly unsaturated
  • Energy used for the germinating seedling to grow
• Energy storage in endotherms

  • Fat is stored in adipocytes as lipid droplets
  • Can be broken down into ATP
• Triglycerides in adipose tissue

  • Energy reserve
  • Thermal insulation
• Triglycerides


  • Compact form of energy storage
  • Store more than double the energy content of carbs
  • Can be broken down to produce ATP through aerobic respiration
• Steroids


  • Lipids with 4 carbon rings + a hydrocarbon chain
  • Mostly hydrophobic
  • Diffuse directly through the phospholipid bilayer
  • Non polar and hydrophobic