Proteins PDF

Proteins  Protein monomers are amino acids Monomers = amino acids – There are 20 different amino acids – Different combinations of these 20 make all proteins – 100,000 different proteins in humans alone! Protein monomers are amino acids Amino acids are composed of 5 parts:...

Proteins  Protein monomers are amino acids Monomers = amino acids – There are 20 different amino acids – Different combinations of these 20 make all proteins – 100,000 different proteins in humans alone! Protein monomers are amino acids Amino acids are composed of 5 parts: – Central carbon atom – Hydrogen – Amino group – Carboxylic acid group – R group = something different for each type of amino acid!  Proteins have multiple uses Purpose of proteins: – Structure = hair, webs, bone – Support/ Movement =muscles – Packaging materials = seed coats – Transport = hemoglobin, channel proteins – Defense = antibodies – Signal/ Messengers = types of hormones – Enzymes = speed up chemical reactions Amino acids are joined together by a peptide bond Amino acids are joined together through the process of dehydration synthesis – This forms the peptide bond – Amino acids linked together are called polypeptides  Polypeptides need to fold in order to function properly Primary structure: the amino acid sequence (usually at least 100 amino acids long)  Polypeptides need to fold in order to function properly Secondary Structure: hydrogen bonds between amino acid groups lead to either alpha helix or beta pleated sheet patterns.  Polypeptides need to fold in order to function properly Tertiary structure: additional chemical bonds and interactions between amino acids lead to a 3D shape.  Polypeptides need to fold in order to function properly Quaternary structure: when a protein consists of more than one polypeptide chain bonded together – Example: Hemoglobin Protein Structure Linear sequence of amino acids Amino acids folded as beta sheets or alpha helix 3D shape of protein Protein Structure Campbell  Protein function is dependent on protein structure The shape of the protein allows it to function. – If the protein loses its shape, it will no longer function properly Denature = unfold a protein – Unfavorable pH and temperature can cause a protein to denature  To detect proteins, we use the biuret test Biuret test = detects the presence of proteins Biuret solution turns from light blue to violet/purple color  Indicator Biuret test: Amino acids are linked together by peptide bonds that react with copper sulfate that is used in the biuret test producing a Violet color. Fold it – Free MMOG that makes protein folding a puzzle! What is it and why is it awesome? http://fold.it/ https://www.youtube.com/watch?v=DvYFjo3vC-k