Proteins

Cards (23)

  • Amino acids are the building blocks of proteins
  • Proteins: composed of Carbon, Hydrogen, Oxygen, Nitrogen, and Sulfur (C, H, O, N, S)
  • Amino acids are the building blocks of proteins and have a general structure consisting of an amino group (NH2), a carboxyl group (COOH), and a side chain
  • There are 20 naturally occurring amino acids, each with a unique side chain that differentiates them from one another
  • The side chain of each amino acid is what differentiates one amino acid from another
  • A dipeptide is formed when two amino acids join together by a peptide bond
  • A polypeptide is formed by many amino acids joining together through condensation reaction
  • Protein structure pt1
    Primary structure
    • It's the number and sequence of amino acids in the the polypeptide chain
    • Determines the structure of the polypeptide and the 3D shape of proteins and their active sites
    • Peptide bonds are involved
  • Proteins have two main secondary structures:
    • Alpha helix: forms a right-handed coil stabilized by hydrogen bonds between amino acids. They make up DNA binding and transmembrane proteins
    • Beta pleated sheets: formed by proteins due to hydrogen bonds between amino acids, creating a sheet-like structure like silk
  • The secondary structure of proteins form two shapes due to hydrogen bonds forming between amino acids
  • Proteins' tertiary structure involves hydrogen bonds, ionic bonds, disulfide bonds, hydrophobic, and hydrophilic interactions
  • The tertiary structure of a protein provides the final 3D shape necessary for its function
  • Haemoglobin is an example of a protein with quaternary structure
  • Quaternary structure is found in proteins that consist of more than one polypeptide chain
  • Globular proteins:
    • Have water inside that pertains a spherical shape
    • Are soluble
    • Involved in metabolic processes because they have hydrophobic and hydrophilic R groups
    • Examples: Haemoglobin, Insulin, and Pepsin
    • The hydrophobic R groups are on the inside, while the hydrophilic ones are on the outside
  • Give three examples of Globular proteins
    1. Haemoglobin
    2. Insulin
    3. Pepsin
  • Examples of fibrous proteins include Collagen, Keratin, and Elastin
  • Globular and fibrous proteins are two main types of protein structure
  • Haemoglobin is a globular protein that carries oxygen in the blood
  • Haemoglobin consists of four polypeptide chains: two alpha and two beta chains
  • Each haemoglobin molecule contains a haem group with iron (Fe2+) that can bind to two oxygen molecules
  • The haem group is a prosthetic group that is embedded in the globular protein structure of haemoglobin
  • Fibrous protein
    • Usually made of long polypeptide chains that form fibres
    • Insoluble due to high number of amino acids with hydrophobic R-groups in their primary structure
    • Flexible