Proteins

Proteins Functions- structural, regulating cell functions (enzymes), antibodies, hormones Functions- structural, regulating cell functions (enzymes), antibodies, hormones Made of chains of amino acids Made of chains of amino acids There are 20 amino acids that are used by all living organisms to make proteins There are 20 amino acids that are used by all living organisms to make proteins Proteins can be any length and any combination of amino acids therefore there are millions of proteins used by living organisms. Proteins can be any length and any combination of amino acids therefore there are millions of proteins used by living organisms.

Amino acids contain an amino group, a carboxyl group, a carbon and a unique R group

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Polar R groups make the amino acid hydrophilic

Ionic R groups make the amino acid hydrophilic

Non-polar R groups make the amino acid hydrophobic

Functions of amino acids Protein synthesis, energy reserve, hormones (thyroxin) Protein synthesis, energy reserve, hormones (thyroxin) 20 different amino acids used in protein synthesis though others do occur in nature. 20 different amino acids used in protein synthesis though others do occur in nature. Essential amino acids cannot be synthesised by the organism and must form part of their diet Essential amino acids cannot be synthesised by the organism and must form part of their diet © 2007 Paul Billiet

NCC-OH R H O H H R H O H H Condensation reaction NCCNCC R H O H H NCC-OH R H O H + H 2 O The peptide bond A dipeptide is formed © 2007 Paul Billiet ODWSODWS Formation of a Dipeptide n.html hydrolysis.html

Formation of a Polypeptide SerineValineTyrosineCysteine 3 H 2 O

Proteins When many amino acids bond together to create long chains, the structure is called a protein (it is also called a polypeptide because it contains many peptide bonds). When many amino acids bond together to create long chains, the structure is called a protein (it is also called a polypeptide because it contains many peptide bonds).