Biological molecules

• Beta glucose

  
• Alpha glucose

  
• Example of polysaccharides

  Starch

  Glycogen

  Cellulose
• Example of disaccharides

  Sucrose

  Maltose

  Lactose
• Example of monosaccharides

  Glucose

  Fructose

  Galactose
• Example of a polymer

  Starch, cellulose, glycogen

  Protein

  DNA, RNA
• Examples of monomers

  Glucose

  Amino acid

  Nucleotide
• Test for proteins


  Biuret test.

  Add sodium hydroxide to the test sample.

  Add a few drops of dilute copper sulfate solution.

  Positive result - solution = violet/purple
• What bond is in secondary structure of proteins?

  Hydrogen bond
• What bonds are in the tertiary structure of proteins?

  Disulfide bridges

  Ionic bonds

  Hydrogen bonds
• What bond is in the primary structure of proteins?

  Peptide bond
• Test for lipids

  Emulsion test: shake a lipid soluble substance in water with the test substance (ethanol) until it turns milky/cloudy, shows a lipid is present
• Test for starch

  Iodine solution

  -Positive: Blue black

  -Negative: Orange yellow
• Test for non-reducing sugars

  Heat with Benedict's

  If negative (stays blue), hydrolyse substance with HCl and neutralise with NaOH. (or hydrolyse with an enzyme)

  Heat with Benedict's Brick red precipitate indicates non- reducing sugar.
• Test for reducing sugars

  Benedict's test. A blue solution, add a few drops to your solution. Heat in a water bath and if reducing sugars are present the benedict's will turn brick red
• Non-competitive inhibitor


  A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate.
• Competitive inhibitors

  Reduce the productivity of enzymes by blocking substrates from entering active sites.
• Enzyme inhibitors

  A chemical that interferes with an enzyme's activity
• Effect of PH on enzyme action

  pH can alter the charges on the amino acids that make up the active side so the enzyme and substrate can no longer join

  If the pH is very extreme then it can alter the bonds of the enzyme and cause it to denature
• Effect of temperature on enzyme action

  Increasing the temperature of a working enzyme initially increases the activity. Enzymes have an optimum temperature, and once this is reached, the activity decreases. Then, past a certain temperature, the active site changes shape, and the enzyme is denatured.
• Induced fit model

  Change in the shape of an enzyme's active site that enhances the fit between the active site and its substrate(s)

  
• Enzyme structure

  the substrate enters the active site on the enzyme. the reaction occurs then the products leave the active site. the active site and enzyme are unchanged
• Quaternary structure of proteins

  Different polypeptide chains, each referred to as a subunit, associate together to form a functional protein.
• Tertiary structure of proteins


  Three-dimensional structure of a peptide, results from hydrophobic and hydrophilic interactions between residues far apart on the chain. Disulfide bonds and hydrogen bonds can also add to the tertiary structure of the protein.
• Secondary structure of proteins

  Regularly repeating local structures such as α-Helices and ß-pleated sheets often formed by hydrogen bonds between residues nearby on the chain.
• Primary structure of proteins

  linear sequence of amino acids
• Formation of a peptide bond

  Two amino acids come together, one oxygen and two hydrogen come together to form water, and then everything comes together to form the peptide bond
• Structure of amino acids

  central carbon, amino group, carboxyl group, R group
• Hydrophobic


  Water fearing
• Hydrophilic


  Attracted to water
• Phospholipids


  A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail. A lipid consisting of a glycerol bound to two fatty acids and a phosphate group.
• Triglycerides


  an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid.
• Roles of lipids

  Source of energy

  Waterproofing

  Insulation

  Protection
• Lipids


  Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.
• Cellulose


  A substance (made of sugars) that is common in the cell walls of many organisms. Made up of monomers of b glucose
• Glycogen


  An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
• Starch


  A storage polysaccharide in plants consisting entirely of glucose. Made up of chains of a glucose monosaccharides.
• Polysaccharides


  Carbohydrates that are made up of more than two monosaccharides
• Disaccharide

  A double sugar molecule made of two monosaccharides bonded together through condensation reaction. Joined together with a glycosidic bond.
• Monosaccharide


  soluble substance that have the general formula (CH2O)n

  e.g. glucose, galactose and fructose