Biological And Chemical Polymers Flashcards
What is required for selective and precise chemistry in terms of polymers?
Needs selective and precise 3D structure
Requires large molecular size- produce an extensive set of intermolecular reactions
High MW does not ensure specificity
What are the limitations of synthetic polymers?
Specificity limitations Repetitive sequence Variable length Limited chemistry Undefined properties
Describe the typical structure of a synthetic polymer
Usually only 1 or a few monomers involved
Linear chain or random branching
Polydisperse- variable MW
Monomer arrangement in copolymers
Usually non specific functionality
Very hard to make polymeric molecule with precise function and recognition properties
What is a biopolymer?
A polymeric substance occurring in living organism
Describe the typical structure of a biopolymer
Very precise composition Precise MW Defined sequence 3D structure Defined function Large number of possible configuration Protein size varies
What does each protein have if it is the same type of protein?
For any one type of protein, all have the same number of amino acids in the same sequence
What are proteins in terms of polymers?
Linear polymer of amino acids linked by peptide bonds
What is special about amino acids?
They are chiral
Building blocks are optically active with only L- a amino acids
Backbone is regular
What is different about amino acid side chains?
They have different physiochemical properties
Why is a specific sequence necessary?
Leads to a defined 3D structure and specific properties
Why are there only 20 amino acids?
This is Less than theoretically possible from genetic code
Evolution has selected appropriate number for optimal cell function
What is the Henderson hasselbach equation?
pH= pKa + log [A-]/[HA]
What does a low pKa mean?
A strong acid
pKa is very similar to actual pH
How do side chains relate to pKa and what happens above and below pKa?
Some chains have ionisable groups
Above pKa value- side chains will donate H
Below pKa value- side chains will accept H
What is the hierarchy of protein structure
Primary- sequence of amino acids
Secondary- regular repeating peptide backbone conformation
Tertiary- full 3D structure of one polypeptide chain
Quaternary- assembly of more than one polypeptide chain
