Proteins Flashcards
Amino Acid Structure
All have the same general structure, only difference is the nature or the R groups
What does the R group represent
A side chain from the central ‘alpha’ carbon atom, can be anything from a simple hydrogen atom to more complex ring structure
Types of amino acids
Glutamine
Aspartic Acid
Lysine
Valine
Whats a dipeptide
Two amino acids together, linked by a peptide bond
Where does the peptide form
Between the carboxyl (COOH) group on one amino and the amino (NH2) group on the other
What sort of reaction is a peptide bond and why
Condensation reaction because of the bond creating water
How can you split a dipeptide up
Hydrolysis reaction
What are the 4 levels of structure in a protein
Primary
Secondary
Tertiary
Quaternary
What sort of structure do proteins have
Unique 3D structure - enables them to carry out specific functions
Whats a proteins primary structure
Sequence of amino acids in polypeptide chains
Whats a proteins secondary structure
Localised 3D sections. A common type of section is the alpha helix
Whats another Secondary structure in a protein
Beta-pleated sheet. Both alpha helix and beta sheet can co-exist in the same protein
How is the shape of the secondary structure maintained
by hydrogen bonds between the C=O group of the amino acid, and the NH group of another
Whats a proteins overall 3D shape
Its tertiary structure. Several types of bonds may hold structure in place, ionic bonds, hydrogen bonds, disulphide bonds and hydrophobic interactions
Whats the arrangements of more than one polypeptide chain in a protein
Quaternary structure
What do conjugated proteins contain
A non-amino acid part called a prosthetic group
Where are hydrogen bonds
Involved in all levels of structure
Where are hydrophobic interations
Between non-polar sections of the proteins
Where are Disulfide bonds
one of strongest and most important type of bond in proteins. Occur between two cysteine amino acids
How are fibrous proteins formed
from parallel polypeptide chains held together by cross-links. These form long rope-like fibres with high tensile strength and generally insoluble in water
Whats collagen
The main component of connective tissue such as ligaments, tenders, cartilage
What is Keratin
The main component of hard structures like hair, nails, claws, hooves
Structure of Globular proteins
Spherical shape caused by tightly folded polypeptide chains
What causes Denatured proteins
When bonds that maintain a proteins shape stop working, the protein will stop working and is now denatured
What can denature a protein
Changes in temperature, pH or salt concentration
What happens to fibrous proteins when denatured
lose their structural strength
What happens to globular proteins when denatured
Become insoluble and inactive
