Membrane proteins ECB Fig. 11-4. Membrane proteins have a variety of functions.
Proteins. Proteins Functions- structural, regulating cell functions (enzymes), antibodies, hormones...
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Transcript of Proteins. Proteins Functions- structural, regulating cell functions (enzymes), antibodies, hormones...
ProteinsProteins
ProteinsProteins Functions- structural, regulating cell Functions- structural, regulating cell
functions (enzymes), antibodies, functions (enzymes), antibodies, hormoneshormones
Made of chains of amino acidsMade of chains of amino acids There are 20 amino acids that are used by There are 20 amino acids that are used by
all living organisms to make proteinsall living organisms to make proteins Proteins can be any length and any Proteins can be any length and any
combination of amino acids therefore there combination of amino acids therefore there are millions of proteins used by living are millions of proteins used by living organisms.organisms.
Amino acids contain an amino Amino acids contain an amino group, a carboxyl group, a carbon group, a carboxyl group, a carbon
and a unique R groupand a unique R group
http://www.biotopics.co.uk/as/aa.html
http://www.johnkyrk.com/aminoacid.html
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 acidsFunctions of amino acids
Protein synthesis, energy reserve, Protein synthesis, energy reserve, hormones (thyroxin)hormones (thyroxin)
20 different amino acids used in protein 20 different amino acids used in protein synthesis though others do occur in nature.synthesis though others do occur in nature.
Essential amino acids cannot be Essential amino acids cannot be synthesised by the organism and must form synthesised by the organism and must form part of their dietpart of their diet
http://www.biotopics.co.uk/JmolApplet/jcontentstable.htmlhttp://www.biotopics.co.uk/JmolApplet/jcontentstable.html http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.htmlhttp://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html
© 2007 Paul Billiet
N C C-OH
R
H
OH
H
N C C-OH
R
H
OH
H
Condensation reaction
N C C
R
H
OH
HN C C-OH
R
H
OH+ H2O
The peptide bond
A dipeptide is formed
© 2007 Paul Billiet ODWS
Formation of a Dipeptide
http://www.biotopics.co.uk/as/aminocon.htmlhttp://www.biotopics.co.uk/as/dipeptidehydrolysis.html
Formation of a PolypeptideFormation of a Polypeptide
Serine Valine Tyrosine Cysteine
3 H2O
ProteinProteinss
When many amino acids bond together to create When many amino acids bond together to create long chains, the structure is called a protein (it is long chains, the structure is called a protein (it is also called a also called a polypeptidepolypeptide because it contains many because it contains many peptide bonds).peptide bonds).