PoH: Proteins Flashcards
Name the 7 classes of AAs
Aliphatic
Aromatic
Acidic
Basic
Polar
Sulphur-Containing
Miscellaneous
What is the difference between an aliphatic and aromatic AA?
In aliphatic, the R group has hydrocarbon chains. In aromatic, the R group has hydrocarbon rings
What characterises sulphur-containing AAs?
(bit more specific than “sulphur”!)
A disulfide bridge - covalently bonded linkages between two sulphide-containing AAs which help increase strength
What is a polar AA?
Have a charge at the end of the R group
What’s the only miscellaneous AA and what’s special about it?
Proline
It has an unusual ring shape and so is incorporated in many tissues needing strength
What’s the primary structure?
Amino Acid Residues
The sequence in which AA monomers are bonded together to form a polypeptide chain
What’s the secondary structure?
Alpha-Helix
The local spatial arrangement of a polypeptide’s backbone (main chain) atoms. It relies on hydrogen bonding between amino hydrogen of one AA and carboxyl oxygen of another AA. It can be an alpha helix or beta-pleated sheet
What’s the tertiary structure
Polypeptide Chain
The 3D structure of an entire polypeptide chain. They happen when the functional groups of ‘R’ chains in AAs interact with each other. They involve Van der Waals, ionic, hydrogen, disulphide bridges and hydrophobic interactions
What’s the quaternary structure?
Assembled subunits
The 3D arrangement of the subunits in a multiunit protein
In which structures do denaturation occur? Primary, secondary, tertiary and/or quaternary?
Secondary and tertiary
It leads to loss of biological function
Name the 8 functions of proteins
Structure
Enzyme
Receptors
Hormones
Transport
Storage
Defence
Contractile
Co-translational modification or post-translational modification results in what sort of proteins?
Conjugated proteins (glycoproteins, lipoproteins, metalloproteins)
Name the three types of conjugated proteins
Glycoproteins
Lipoproteins
Metalloproteins
What are glycoproteins, and what four things does it achieve?
Proteins with 1 or more covalently attached carbohydrates
Stability
Solubility
Cell signalling
Orientation
A glycoprotein with a few monomers in a chain is called what?
Oligosaccharide
What are lipoproteins? Where are they found? What do they do?
Proteins combined with lipids
Found in cell membranes
Transport hydrophobic molecules (e.g. cholesterol in blood)
Lipoproteins can also form complexes with other lipoproteins, forming apolipoproteins (they transport fats, fat-soluble vitamins and fat soluble hormones)
What are apolipoproteins and what do they do?
When lipoproteins form complexes with other lipoproteins.
They transport fats, fat-soluble vitamins and fat soluble hormones?
What are metalloproteins and what do they do?
Proteins with metal ions in their structures (co-factors). They include enzymatic, signal transduction, transport and storage.
What two ways can proteins be classed on their functions?
Globular and fibrous
What 5 functions do globular proteins do?
Storage
Enzymes
Hormones
Transporters
Structure
What 2 anatomical features do fibrous proteins do?
Muscle fibres
Connective tissues
What 4 things can membrane proteins be, and what do they do?
Membrane transporter
membrane enzymes
cell adhesion molecules
signalling
