Unit 2 Section 1.2 Proteins
- Created by: stephloupoole
- Created on: 18-04-14 19:00
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- Proteins
- what are proteins made from?
- proteins are polymers. these are large complex molecules composed of long chains of monomers
- the monomer of proteins are amino acids.
- a dipeptide is formed when more than two amino acids join together
- a polypeptide is formed when more than two amino acids join together.
- proteins are made up of one or more polypeptides
- a polypeptide is formed when more than two amino acids join together.
- a dipeptide is formed when more than two amino acids join together
- the monomer of proteins are amino acids.
- proteins are polymers. these are large complex molecules composed of long chains of monomers
- Amino acid structure
- all amino acids have the same general structure
- a carboxyl group (-COOH) and an amino group (-NH2) attached to a carbon atom. the difference between different amino acids is the variable group they contain
- all amino acids have the same general structure
- Polypeptide Formation
- amino acids are linked together by condensation reactions to form dipeptide and polypeptides. a molecule of water is released during the reaction
- the bonds formed between amino acids are called peptide bonds. a peptide bond forms between the amino group of one amino acid and the carboxyl group of another amino acid
- the reverse reaction adds a molecule of water to break the peptide bond - this is called a hydrolysis reacion
- Protein Structure
- proteins are big, complicated molecules
- they're much easier to explain if you describe their structure in four 'levels'. these levels are a proteins primary secondary and tertiary and quaternary structures.
- the four structural levels of a protein are held together by different kinds of bonds
- Primary Structure
- this is the sequence of amino acids in the polypeptide chain.
- it is held together by the peptide bonds between amino acids
- this is the sequence of amino acids in the polypeptide chain.
- Secondary structure
- the polypeptide chain doesnt remain flat and straight
- Hyrogen bonds form between the -NH and -CO groups of amino acids in the chain
- this makes it automatically curl into a alpha helix or fold into a beta pleated sheet
- Hyrogen bonds form between the -NH and -CO groups of amino acids in the chain
- the polypeptide chain doesnt remain flat and straight
- Tertiary Structure
- the coiled or folded chain of amino acids is often coiled and folded further.
- more bonds form between different parts of the polypeptide chain such as
- Ionic Interactions, Disulfide bridges, Hydrophobic and hydrophilic interactions and hydrogen bonds
- more bonds form between different parts of the polypeptide chain such as
- the coiled or folded chain of amino acids is often coiled and folded further.
- Quaternary structure
- Functions of Proteins
- a proteins shape relates to its function
- Fibrous Proteins
- are tough and rope - shaped. they tend to be found in connective tisssue eg tendons
- Globular proteins
- are round and compact. they're soluble, so they're easily transported in fluids
- Fibrous Proteins
- a proteins shape relates to its function
- what are proteins made from?
- some proteins are made of two or more polypeptide chains held together by bonds
- the quaternary structure is the way these poly peptide chains are assembled together
- it tends to be determined by the tertiary structure of the individual polypeptide chains
- because of this, it can be influenced by all the bonds mentioned above
- it tends to be determined by the tertiary structure of the individual polypeptide chains
- Quaternary structure
- the quaternary structure is the way these poly peptide chains are assembled together
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