Molecular Building Blocks Flashcards
What is the primary sequence
Sequence of amino acids
What are the bonds in primary sequence
Peptide bonds
What is the secondary sequence
Local spatial arrangement of polypeptide backbone
What are the bonds of the secondary sequence
Hydrogen bonds
Describe alpha helix
Regular patterns of hydrogen bonds between the backbones of nearby amino acids
Describe beta sheet
Backbone of hydrogen bonds interact side by side
Describe the tertiary structure
3D structure of whole polypeptide including side chains
What are the bonds in the tertiary structure
Ionic interactions
Van der Waals forces
Sulphur bridges
What is the quaternary structure
Assembly of several polypeptide chains
What are the stabilising bonds in a helix
i + 4
Describe Van der Waals forces
Electrostatic interactions between movement of electrons within a molecule giving an interaction
Describe hydrogen bonds
Polar molecule (water)
Between H and O
Describe ionic bonds
Salt bridges
Occur through the association of two charged amino acid groups
Electrostatic interactions
Form weak bonds
Describe hydrophobic forces
Tendency of non polar molecules to cluster together #
Very important - amino acids categorised for degree of hydrophobicity
Describe disulphide bonds
Formed between two cystines
Covalent bond
Primary structure
Internal environment of cytoplasm does not favour these bonds - formed in the ER
Oxidation reaction
What is the structure of amino acids
NH3 - CHR - COOH
Amino group - N terminus
Carboxyl group - C terminus
What is the role of the R group in amino acids
Specific features according to its polarity and charge - which then effects the chemical and biological properties of the protein
How many amino acids are there
21
What are essential amino acids
9 amino acids must be consumed in the diet
