2.2 Biological molecules

• A triglyceride is a glycerol molecule and 3 fatty acids.
• glucose general formula is CnH2nOn
• The covalent bond that connects sugars is a glycosidic bond.
• A disaccharide is a molecule made up of two monosaccharides joined by a glycosidic bond, e.g sucrose, lactose and maltose.
• Isomer is a molecule with the same molecular formula but a different structural formula
• A monosaccharide is a simple sugar that is a single sugar molecule.
• Water has many different properties like adhesion, cohesion, thermoregulation, 3 different states.
• The hydrolysis reaction is the breaking of a chemical bond between two molecules.
• A condensation reaction is a reaction in which two molecules join together to form a covalent bond.
• The 4 key chemical elements in the body are Carbon, Hydrogen, Oxygen and Nitrogen
• The three type of fatty acid are saturated, monounsaturated and polyunsaturated
• lipids are made up of carbon, hydrogen and oxygen atoms and are used for energy storage and insulation
• A polysaccharide is a polymer of monosaccharides, like cellulose, chitin, glycogen and starch
• An ester bond joins lipids together (fatty acid -> gylcerol).
• Triglycerides functions are as an energy source, energy store and insulation.
• A phospholipid is a lipid that contains a phosphate group that replaces one of the fatty acids.
• The phospholipid bilayer is a barrier to diffusion of small molecules and ions made up of phospholipid molecules.
• A protein is a molecule that is made up of amino acids.
• Proteins uses are structure, transport, enzymes, hormones, antibodies.
• A peptide bond joins proteins together.
• The primary structure of a protein is the chain of amino acids
• The secondary structure is the folding of the polypeptide chain made of amino acids into alpha helixes and beta sheets
• The tertiary structure is the 3D shape of the protein in coils and pleats that is determined by the interactions between the amino acids, held together by different bonds.
• The quaternary structure is when the protein has more than one polypeptide chain.
• Proteins functions are: transport, store, build, enzymes, movement, repair, and regulate.
• Fibrous proteins are made up of long chains of amino acids. They are insoluble in water. Examples are collagen, elastin and keratin.
• Globular proteins are compact and spherical in shape. Examples are enzymes, hormones and haemoglobin.
• Adhesion means that water likes to stick to other things
• Cohesion means water likes to stick to itself and other water molecules.
• A property of water is Specific heat capacity which is the ability of a substance to store and release heat energy.
• Water has high specific heat capacity because it takes more energy to change its temperature than most liquids.
• Water has a high latent heat of vaporisation which is the heat that has to be given to a unit mass of material to convert it from the liquid to the vapor phase without a change in temperature.
• Water has a high surface tension which is The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules
• Carbohydrates are made of carbon, oxygen and hydrogen.
• Proteins are made of carbon, hydrogen, oxygen and nitrogen.
• Lipids are made of carbon, oxygen and hydrogen.
• Amino acid structure

  
• The chemical tests for biology are: biuret test for proteins, Benedict’s test for reducing and non-reducing sugars, iodine test for starch and emulsion test for lipids.
• Rf value equation for chromotography

  
• Thin layer chromatography (TLC) uses a thin layer of silica gel instead of paper as the stationary phase and can be done with visible light or UV light.