Proteins Flashcards
What is a protein made from
One or more polypeptides bonded together
What is the general structure of amino acids
A carboxyl group (-COOH), an amino group (−NH2), an R group (a variable group and a hydrogen atom - all bonded to one carbon atom. (R groups generally contain carbon, except for glycerine)
What makes the difference between each amino acid
What makes up the R group
What are bonds between amino acids called
Peptide bonds
What are the 4 names of the different protein structures
Primary Structure, Secondary Structure, Tertiary Structure, Quaternary Structure
What is the Primary structure
The flat and straight sequence of amino acids in the polypeptide chain
What is the Secondary structure
Hydrogen Bonds form between amino acids in the chain. Which makes the chain either coil into an alpha helix or fold into a Beta pleated sheet.
What is the Tertiary structure
Coiled or folded further. More bonds form between different parts of the chain, including hydrogen bonds and ionic bonds. Disulfide bridges also form when two molecules of the amino acid cysteine come close together - the sulfur atom in one cysteine bonds to the sulfur in another. (Cysteine = Non-essential amino acids containing sulfur)
What is the Quaternary structure
The way in which several polypeptide chains are assembled together. For proteins made from more than one polypeptide chain, the quaternary structure is their final 3D structure.
Name 3 proteins containing more than one polypeptide chain
Haemoglobin, insulin, collagen
How does Haemoglobin’s shape determine its function
It is a compact, soluble protein, which makes it easy to transport. Therefore, great for arguing oxygen around the body.
Enzymes shape and function
Roughly spherical, due to tight folding of polypeptide chains, soluble and often have roles in metabolism. Other enzymes help to synthesise (make) large molecules.
Antibodies shape and function
Made from 2 light (short) polypeptide chains and two heavy (long) polypeptide chains. Involved in the immune system response, found in blood.
Transport proteins shape and function
Contain Hydrophobic and Hydrophilic amino acids, causes protein to fold up and form a channel. Present in cell membrane and transport molecules and ions across membranes.
Structural proteins shape and function
Physically strong, consist of long polypeptide chains lying parallel to each other with cross - links between them.
