proteins

• How many amino acids are required to form a dipeptide?

  Two
• What is a polypeptide?

  An organic polymer than is made of more than two amino acids.
• What is the general structure of amino acids?

  A carboxyl group, an amino group and an R group.
• How many different amino acids make up all living things?

  20
• What is the R group?

  The variable group that differentiates the amino acids
• What reactions form polypeptides?

  Condensation
• What is the bond between amino acids in polypeptides called?

  Peptide bonds
• What are the four structural levels in a protein?


  Primary, Secondary, Tertiary and Quarternary
• What is the primary structure in a protein?

  The sequence of amino acids in the polypeptide chain.
• What is the secondary structure in a protein?

  Hydrogen bonds between amino acids. This forces the chain to either become an alpha coil or beta pleated sheet
• What is the tertiary structure in a protein?

  More bonds (hydrogen or ionic) form between parts of the polypeptide chain.

  When the two molecules of the amino acid cysteine are close then disulfide bridges form. (a sulfur atom from each amino acid bonds)

  This forms a 3D structure.
• What is the quarternary structure of a protein?


  If there are several different polypeptides then the connections between these polypeptides is the quarternary structure.

  Or the quarternary structure is the final 3D structure
• What is an enzyme?


  A specialised, soluble protein that often has roles in metabolism
• What is an antibody?


  A specialised protein that is involved with immune response.
• Describe the basic structure of anitbodies

  Two light polypeptide chains and two heavy polypeptide chains
• Where are transport proteins located?

  Cell membranes
• What is the role of transport proteins?

  Transports molecules and ions across the cell membrane through a channel created in the proteins due to folds.
• What are two types of amino acids are present in transport proteins?

  Hydrophobic and hydrophilic
• What is the structure of structural proteins?

  Long, parallel polypeptide chains with cross links
• What is in structural proteins?

  Keratin and collagen
• What test is for proteins?

  Biuret Test
• What is the first stage of the Biuret test?

  Add sodium hydroxide solution to the test solution so it is an alkaline solution
• What is the second stage of the Biuret test?

  Add copper (II) sulphate solution to the alkaline test solution
• What is a positive result for the Biuret test?

  Purple