Summary Knowledge clips

A snapshot of the summary - Knowledge clips

• 1 Proteins

• 1.1.1 Structure and terminology- amino acids

• How is a C-atom with different atoms on every side called?

  Chiral atom
• What is the difference and occurrence of the 2 stereoisomers?

  L is on the left, occurs in nature. D is on the right and is present after processing, it is non-digestible to humans.
• What is the difference between the alpha and beta amino-acid?

  Alpha is the C atom next to the functional carbonyl (COOH) group, beta is the C atom next to it. Note: both of them can have a NH3 attached.
• How can amino acids be classified based on side-chain?

  • Non-polar, non-charged
    
  • Polar, non-charged
  • Polar, charged
    
• How can amino acids be classified based on nutritional value?

  • Essential
    
  • Conditionally essential
  • Non-essential

• 1.1.2 Structure and terminology- peptides

• In what situations does the trans or cis conformation of a peptide take place?

  Trans --> in nature
  
  Cis --> after processing

• 1.1.3 Structure and terminology- proteins

• Mention 3 system conditions that can change the structure of proteins

  1. Temperature
     
  2. pH and ionic strength
  3. Solvent
     
• Which 3 different types of interactions stabilise the quaternary structure of proteins?

  1. Hydrophobic interactions
     
  2. Disulfide bonds
  3. Charge
• What can the presence of a reducing agent do to structural forces used for protein folding and stability?

  It can break the disulphide bonds (S-S).

• 1.1.4 Structure and terminology- protein classification

• Give examples of the classes of proteins based on structure and give their natural solubility

  • Globular (blood, soy) --> high
    
  • Fibrillar (gelatin, meat) --> low
  • Random coil (caseins) --> high
  • Other (gluten) --> low