Haemoglobin and Protein

1  The tertiary structure of a protein is the

• bonding together of several polypeptide chains by weak bonds.
• order in which amino acids are joined in a peptide chain.
• twisting of a peptide chain into an α-helix.
• three-dimensional shape.

1  At which level of protein structure are interactions between R groups most important?

• primary
• secondary
• tertiary
• quaternary

1  The correct shape of a globular protein is maintained by several types of bond.   
1 = disulfide 2 = hydrogen 3 = ionic 
4  = peptide  
Which bond types are involved in maintaining the different levels of structural complexity of a globular protein?

• Primary: 4 
  Secondary:3
   Tertiary:1,2,3
• Primary: 2 
  Secondary:1
   Tertiary:2,3,4
• Primary: 2 
  Secondary:4
   Tertiary:2,3,4
• Primary: 4 
  Secondary:2
   Tertiary:1,2,3

The diagram shows a haemoglobin molecule. Which identifies the different parts of the molecule?

• 1: alpha helix, 2: beta pleated sheet, 3: binding site, 4: hydrophobic amino acids
  
• 1: hydrophobic amino acids, 2: beta pleated sheet, 3: prosthetic group, 4: binding site
• 1: prosthetic group, 2: hydrophobic amino acids, 3: alpha helix , 4: hydrophilic amino acids
• 1: prosthetic group, 2: hydrophilic amino acids, 3: alpha helix , 4: hydrophobic amino acids

1  Which of the following statement(s) is/are true?  
   1:The binding of one oxygen molecule to one subunit causes a conformational change in the other subunits, decreasing their affinity to other oxygen molecules.
 2: Hydrogen bonds, ionic bonds, hydrophobic interactions and disulphide bonds maintain the specific 3-dimensional configuration of each haemoglobin subunit.
3: The globular structure of haemoglobin makes it compact and soluble, which allows many haemoglobin molecules to be packed in the cytoplasm of red blood cells.

• 2 only
• 3 only
• 2 and 3 only
• 1,2 and 3