globular proteins

• What is the shape of globular proteins?

  Roughly spherical
• Why do globular proteins fold into a spherical shape?

  Due to the orientation of R groups
• How do non-polar R groups behave in globular proteins?

  They orient towards the protein's center
• What is the role of polar R groups in globular proteins?

  They orient on the outside for solubility
• Why are globular proteins generally soluble in water?

  Water surrounds the polar hydrophilic R groups
• What physiological roles do globular proteins play?

  Transport and metabolic reactions
• How does the folding of globular proteins affect their function?

  It gives them specific shapes for roles
• What are conjugated proteins?

  Proteins containing a prosthetic group
• What is the structure of haemoglobin?

  It has a quaternary structure with four chains
• What types of globin proteins are in haemoglobin?

  Two a-globins and two B-globins
• How are the globin subunits of haemoglobin held together?

  By disulphide bonds
• What is the significance of the orientation of R groups in haemoglobin?

  It helps maintain its spherical shape and solubility
• What happens if the amino acid sequence in haemoglobin changes?

  It can alter haemoglobin's properties
• What condition is caused by a change in haemoglobin's amino acid sequence?

  Sickle cell anaemia
• What causes the change in amino acid in sickle cell anaemia?

  A base substitution in the DNA
• What is the effect of valine replacing glutamic acid in haemoglobin?

  It makes haemoglobin less soluble
• What ion does the prosthetic haem group contain?

  Iron II ion (Fe2+)
• What does the iron II ion in haemoglobin do?

  It combines reversibly with oxygen
• What is formed when iron II ion combines with oxygen?

  Oxyhaemoglobin
• What color does haemoglobin appear when it carries oxygen?

  Bright red
• How many oxygen molecules can one haemoglobin carry?

  Four oxygen molecules
• How many oxygen atoms can one haemoglobin carry?

  Eight oxygen atoms
• What is the primary function of haemoglobin?

  Binding oxygen and transporting it
• Why is oxygen carried more efficiently when bound to haemoglobin?

  Because oxygen is not very soluble in water
• How does the binding of oxygen affect the structure of haemoglobin?

  It alters the quaternary structure of the protein
• What role does the iron II ion (Fe2+) play in haemoglobin?

  It allows reversible binding of oxygen
• What type of proteins are enzymes classified as?

  Globular proteins
• What is the function of enzymes in living systems?

  They speed up chemical reactions
• What is the active site of an enzyme?

  The region where the substrate binds
• How do enzymes control metabolic pathways?

  • Enzymes regulate biochemical reactions
  • They facilitate a cascade of reactions
  • Essential for metabolic processes
• Why are enzymes essential for life?

  They catalyze virtually every metabolic reaction
• How do enzymes remain unchanged during reactions?

  They are not used up in reactions
• What does it mean for enzymes to be biological catalysts?

  They function in living systems
• What is the significance of the quaternary structure in haemoglobin's function?

  It enhances the binding affinity for oxygen
• What was the first protein to have its sequence determined?

  Insulin
• What happens to haemoglobin's affinity for oxygen as more oxygen binds?

  It increases with each binding event
• What type of protein is insulin?

  Globular protein
• Where is insulin produced in the body?

  In the pancreas
• What role does insulin play in the body?

  Controls blood glucose concentration
• How many polypeptide chains does insulin consist of?

  Two polypeptide chains