Biological Molecules

• What are proteins made from?

  Amino acids joined by peptide bonds
• What is one function of proteins in the body?

  Provide structure and support to tissues
• How do proteins control aspects of metabolism?

  As hormones and enzymes
• What is the role of water-soluble proteins in body fluids?

  Storage and transport of molecules
• What is the role of immunoglobulin G?

  Provide protection against invaders
• Why is the overall shape of a protein important?

  It is essential for its metabolic role
• What type of amino acids are found in proteins?

  Alpha-amino acids
• What distinguishes each alpha-amino acid?

  Each has a different R group

  
• How many common amino acids are there?

  20 common amino acids

  
• What is the nature of the common proteogenic amino acids?

  All are of the S-configuration
• How many common amino acids have readily ionisable side chains?

  7 of the 20 common amino acids

  
• What two groups do amino acids contain?

  Acidic group and basic group
• What is a zwitterion?

  A neutral dipolar ion with charges

  
• What happens to zwitterions in acidic solutions?

  They accept protons on basic groups

  
• What happens to zwitterions in basic solutions?

  They lose protons from acidic groups

  
• What does the isoelectric point (pI) indicate?

  The pH where net charge = 0
• Why do isoelectric points vary among amino acids?

  Due to the influence of the side chain
• How do side chain interactions affect protein structure?

  They stabilize protein structure
• What influences protein solubility?

  Isoelectric points of amino acids
• What is a peptide bond?

  An amide bond linking two amino acids

  
• What results from the formation of a peptide bond?

  A dipeptide from two amino acids

  
• What is a polypeptide?

  A chain of many amino acids
• What is the structure of a dipeptide?

  Peptide bond between two amino acids

  
• What determines a protein's function?

  The sequence of amino acids and side chains
• What types of forces act between amino acids?

  Hydrogen bonding, Van der Waals forces, ionic interactions
• What is a disulfide bond?

  A covalent bond between two cysteines

  
• How do nonpolar side chains behave in water?

  They cluster to avoid aqueous fluids
• What is the primary structure of a protein?

  The sequence of amino acids in a chain

  
• What is the secondary structure of a protein?

  The arrangement of the polypeptide chain

  
• What stabilizes the secondary structure of proteins?

  Hydrogen bonds between backbone atoms

  
• What is tertiary protein structure?

  The specific three-dimensional shape of a protein

  
• What is a native protein?

  A protein with its functional shape
• What is quaternary protein structure?

  Aggregation of two or more protein chains

  
• How are polypeptides primarily held together?

  By noncovalent forces
• What are the two ends of a protein chain?

  Amino end and carboxyl end
• What is a secondary structure of proteins?

  b-Sheet

  
• What determines the folding of a protein molecule?

  Its primary structure

  
• What is a simple protein composed of?

  Amino acid residues only
• What is the quaternary protein structure?

  Aggregation of two or more protein chains

  
• What primarily holds polypeptides together?

  Noncovalent forces