Biological molecules

Cards (49)

  • Monomers examples

    • glucose
    • amino acids
    • nucleotides
  • Polymers examples
    • starch
    • cellulose
    • glycogen
    • proteins
    • DNA
    • RNA
  • Describe a condensation reaction to create polymers
    1. Joining two molecules together
    2. Creating a chemical bond
    3. Removing water
  • Describe a hydrolysis reaction to break apart monomers
    1. Breaking of a chemical bond between two molecules
    2. Involves the use of water
  • Carbohydrate monosaccharides
    • glucose
    • fructose
    • galactose
  • Carbohydrate disaccharides
    • sucrose
    • maltose
    • lactose
  • Carbohydrate polysaccharides
    • starch
    • cellulose
    • glycogen
  • Alpha glucose

    Hydrogen atom on top, hydroxyl group on bottom of carbon 1
  • Beta glucose
    Hydroxyl group on top, hydrogen atom on bottom of carbon 1
  • Glycosidic bond
    Chemical bond that forms between two monosaccharides in disaccharides
  • Starch
    • Glucose store in plants
    • Made from alpha glucose
  • Cellulose
    • Structural strength in plant cell walls
    • Made from beta glucose
  • Glycogen
    • Glucose store in animals
    • Made from alpha glucose
    • Highly branched structure
  • Triglycerides
    Lipid with 3 fatty acid chains attached to a glycerol molecule
  • Phospholipids
    Lipid with 2 fatty acid chains and a phosphate group attached to a glycerol molecule
  • Formation of triglycerides
    1. 3 condensation reactions
    2. 3 water molecules lost
    3. 3 ester bonds formed
  • Triglycerides
    • High ratio of energy-storing carbon-hydrogen bonds
    • Can act as metabolic water source
    • Do not affect water potential
  • Phospholipids
    • Hydrophilic head, hydrophobic tails
    • Form a bilayer in water
  • Amino acid
    Central carbon, hydrogen, amine group, carboxyl group, variable R group
  • Formation of dipeptide
    1. Condensation reaction
    2. Water removed
    3. Peptide bond formed
  • Formation of polypeptide
    1. Multiple condensation reactions
    2. Multiple peptide bonds formed
  • Levels of protein structure

    • Primary
    • Secondary
    • Tertiary
    • Quaternary
  • Primary structure
    Sequence of amino acids in polypeptide chain
  • Secondary structure
    Folding into alpha helix or beta pleated sheet, held by hydrogen bonds
  • Tertiary structure

    Further folding into unique 3D shape, held by ionic, hydrogen and disulfide bonds
  • Quaternary structure

    Multiple polypeptide chains in a single protein
  • Enzymes
    • Proteins in tertiary structure
    • Catalyze reactions by lowering activation energy
    • Have specific active sites complementary to substrates
  • Induced fit model
    Enzyme active site slightly changes shape to mold around substrate
  • Factors affecting enzyme-controlled reaction rate

    • Temperature
    • pH
    • Substrate concentration
    • Enzyme concentration
    • Inhibitors
  • Lower temperature

    Less kinetic energy, fewer successful collisions, fewer enzyme-substrate complexes, lower reaction rate
  • pH away from optimum

    Enzyme denaturing, loss of active site shape, fewer enzyme-substrate complexes, lower reaction rate
  • Increasing substrate concentration
    More collisions, more enzyme-substrate complexes, higher reaction rate until active sites saturated
  • Increasing enzyme concentration

    More active sites available, higher reaction rate until substrate becomes limiting
  • Competitive inhibitor

    Binds to active site, preventing substrate binding
  • Non-competitive inhibitor

    Binds elsewhere on enzyme, changing active site shape
  • Competitive inhibitor

    Binds to the active site of an enzyme, preventing the substrate from binding
  • Non-competitive inhibitor

    Binds to the allosteric site of an enzyme, changing the shape of the active site and preventing the substrate from binding
  • Biochemical test for starch

    1. Add iodine
    2. Positive test result: iodine goes from orangey brown to blue black
  • Biochemical test for reducing sugars
    1. Add Benedict's reagent and heat
    2. Positive test result: solution turns green, yellow, orange or brick red (depending on concentration)
  • Biochemical test for non-reducing sugars

    1. Perform Benedict's test for reducing sugars (negative result)
    2. Add acid and boil
    3. Cool and neutralise
    4. Add Benedict's reagent and heat
    5. Positive test result: solution turns orange or brick red