protein

• what are peptides?


  Polymers made up of amino acid molecules
• What elements make up proteins?

  carbon, hydrogen, oxygen, nitrogen
• what are peptides?

  Polymers made up of amino acid molecules
• What elements make up proteins?

  carbon, hydrogen, oxygen, nitrogen
• what do proteins consist of?

  1 or more polpeptide arranged as complex macromolecules
• where are R groups found?

  in amino acids
• what are R groups also called?

  variable groups
• what are R groups


  Side chains on an amino acid
• what type of bond is formed during the synthesis of peptides?

  a peptide bond
• describe the synthesis of peptides

  1. amino acids join together when the alien and carboxylic groups react

  2. the hydrogen in the carboxyl group of one amino acid reacts with a hydrogen in the anime group of another amino acid

  3. a peptide bond is formed and water is produced (condensation reaction)

  4. results in a dipeptide
• how are polypeptides formed?

  By the condensation of many amino acids. (lots of dipeptides join together)
• how are peptides broken?

  hydrolysis
• what are proteases?


  enzymes that break down proteins
• names of protein level structures

  primary, secondary, tertiary, quaternary
• primary level structure


  -the SEQUENCE in which the amino acids are joined (the formation ion polypeptide chains)

  -directed by information in the DNA

  -peptide bonds
• secondary structure


  -the oxygen, carbon. hydrogen and nitrogen interact - only the carboxylic and amino groups

  -hydrogen or polypeptide bonds form
• secondary structure- alpha helix structure


  hydrogen bonds may form within amino acid chains, pulling it into a coil shape
• secondary structure- beta pleated sheet


  polypeptide chains can lie in parallel with each other, joined by hydrogen bonds, forming sheet like structures. the pattern formed by the individual amino acids causes the structure to appear plated
• tertiary structure


  the folding of protein into its final shape- happens when the R groups of different amino acids are close together so start to interact and fold
• interactions between R groups in tertiary structure names

  hydrophobic and hydrophilic interactions

  hydrogen bonds

  ionic bonds

  disulphide bonds
• hydrophobic and hydrophilic interactions

  Weak interactions between polar and non-polar R-groups
• hydrogen bond


  -weakest bond

  - form between polar R groups
• ionic bond


  formed between oppositely charged R groups
• disulphide bonds


  Bonds between amino acids with sulphur in their R groups. Strong.
• quaternary structure


  Results from two or more polypeptide subunits.

  OPTIONAL
• 2 types of protein

  fibrous and globular
• Are globular proteins soluble in water?

  yes
• Are fibrous proteins soluble in water?

  No, they are insoluble
• globular shape


  roughly spherical
• When do globular proteins form?


  When proteins fold into their tertiary structures in such a way that the hydrophobic R-groups on the amino acids are kept away from the aqueous environment
• function of globular proteins

  metabolic
• what is the sequence of amino acids in globular proteins?

  hydrophilic amino acids on the outside and hydrophobic amino acids in the inside
• Stability of globular proteins

  relatively unstable
• insulin function


  regulation of blood glucose concentration
• why does insulin need to be soluble?


  its transported in the blood stream
• What is haemoglobin?


  red oxygen carrying pigment found in red blood cells
• What structure is haemoglobin?

  quaternary
• why is haemoglobin a quaternary structure?

  has more than 1 subunit: 4 polypeptides, 2 alpha subunits, 2 beta subunits
• what does each subunit in haemolgobin contain?

  a prosthetic haem group which enables it to transport oxygen around the body
• Examples of conjugated proteins


  Haemoglobin and catalase