Functions

• give the 4 things that proteins can be ?

  enzymes

  antibodies

  transport proteins

  structural proteins
• there are loads of different proteins found in living organisms. they all have different structures and shapes , which makes them specialised to carry out particular jobs
• Describe the structure of enzymes?

  • usually spherical in shape due to the tight folding of the polypeptide chains
• why are enzymes usually spherical in shape?

  due to the tight folding of the polypeptide chains
• describe some properties of enzymes?

  • soluble
  • often have roles in metabolism
  • eg some enzymes break down large food molecules and some enzymes synthesise large molecules
• what are antibodies involved in?

  the immune response
• what are antibodies made up of?

  Two light (short) polypeptide chains and two heavy (long) polypeptide chains bonded together/
• what do antibodies have?

  variable regions - the amino acid sequences in these regions vary greatly
• give an example of a transport protein?

  Channel proteins - present in cell membranes
• where are channel proteins present?

  cell membranes
• what are channel proteins a type of?


  transport protein
• what do Channel proteins contain?

  • Hydrophobic and hydrophilic amino acids, which cause the protein to FOLD UP and form a channel
• what do channel proteins do?


  transport molecules and ions acrosss membranes
• what can structural proteins be described as?

  physically strong
• what do structural proteins consist of?

  • Long polypeptide chains lying PARALLEL to each other with CROSS-LINKS between them
• give 2 examples of structural proteins?

  keratin and collagen
• where's keratin found?

  in hair and nails
• where is collagen found?

  in connective tissue