Module 2 - Nucleotides and Nucleic acid

What are amino acids?

building blocks of proteins which are essential macromolecules - monomers when joined to another is a dipeptide and the polymer is polypeptide

What are the roles of protein?

1.Enzymes - proteins used to breakdown + synthesise molecules
2.Antibodies - proteins involved in immune response
3.Transport - some proteins move molecules or ions across membrane
4.Structural components - protein such as keratin + collagen used to create strong fibres 
5.Hormones - some proteins act as chemical messengers in the body
6.Muscle contraction - muscles are made up of proteins

What is the structure of amino acids?

20 different amino acids + all have same general structure of - central carbon atom - amino group (-NH2) - carboxyl group (-COOH) - hydrogen atom (-H) - an R group (each amino acid has different R group which determines its properties) eg cysteine contains a sulphur atoms allowing it to form disulphide bonds

How are dipeptides synthesised?

dipeptides are synthesised via condensation reactions - when two amino acids join the hydroxyl (OH) in carboxyl group of 1 amino acid react with the hydrogen (H) in amino group of another - releases a water molecule and forms a peptide bond between carbon of 1 and nitrogen of another 

How are dipeptides broken down?

dipeptides are broken down via hydrolysis reactions - when a water molecule is added to dipeptide the peptide bond is broken to release the two amino acids

What is the test for proteins?

to find out whether a sample contains peptide bonds (hence proteins) you must carry out Biuret test
steps 1. place food sample in test tube 2. add equal volumw of Biuret solution (sodium hydroxide and copper sulphate) 3. if proteins are present,solution will turn from blue to purple - if no protein is present solution remains blue

What are the four structures of protein?

proteins are large,complex molecules with unique 3D structures where there are four main levels: primary - secondary - tertiary - quaternary
each level has specifc bonds influencing overall shape 

What is the primary structure of protein?

made up of unique sequence of amino acids in polypeptide chain where structure held together by peptide bonds where a change to just one of the amino acids in chain can result in change to proteins structure and function

What is the secondary structure of protein?

involves hydrogen bonds forming between the amino group of one amino acid and carboxyl group of another amino acid further down chain - causes polypeptide chain to coil into either an alpha helix or beta-pleated sheet structure

alpha-helix

beta-pleated