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Macromolecules – Day 1. PROTEINS. BACKGROUND. “molecule of action” Cause most things in your body to happen – to do work Sources of protein: Location of protein within your body: muscles, hair, fingernails, in cells as enzymes. EWW!. STRUCTURE OF PROTEIN.
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Macromolecules – Day 1 PROTEINS
BACKGROUND • “molecule of action” • Cause most things in your body to happen – to do work • Sources of protein: • Location of protein within your body: muscles, hair, fingernails, in cells as enzymes
STRUCTURE OF PROTEIN • All proteins have the same basic structure: • They are unbranched polymers of amino acids (a.a.) Polymer: long chain of connected units – each unit is a monomer • In proteins specifically, the “chain” is a polypeptide and each “link” is an amino acid • The linkage that forms between a.a. units is called a peptide bond
Amino Acids (a.a.) • There are 20 different a.a. • 8 of the 20 a.a. are essential a.a. which the human body cannot produce so these a.a. must be obtained from food • All a.a. have the same basic structure: • They are small molecules with a central carbon atom attached to: • An amino group • A carboxyl group • A hydrogen atom • *A side chain (R)* - the structure of the R makes each a.a. different
Structure of Protein Con’t • Proteins can have one hundred to thousands of a.a. in their chain • a.a.’s may appear in a protein many times • The order of the a.a.’s determines the shape of the protein • The shape of the protein determines its job
Diagram of a Protein (polypeptide): CYSTEINE LEUCINE SERINE LYSINE Peptide Bond Amino Acid (monomer)
ENZYMES • Type of protein that speeds up chemical reactions • Needed to speed up almost every reaction that occurs in living organisms • Reusable • The active site is the location where the chemical reactions take place • E.g. salivary amylase – breaks down sugars in your mouth
HORMONES • Type of protein that acts as a chemical messenger • E.g. insulin – regulates blood sugar levels • E.g. Human growth hormone (HGH)
DENATURATION OF PROTEINS • Changing the shape of the protein caused by changes in the environment may/does stop the protein from doing its job • Protein’s functions usually return when environmental factor is removed, as long as the peptide bonds between a.a. have not been broken
Denaturation Con’t • Denaturation of proteins (including enzymes) can be caused by exposure to: • Extremely high temperatures (above 40oC) • Acids/bases (pH) • Salty environments • High sugar
Application of Denaturing Proteins • Fever above 39oC is dangerous since it may denature critical brain enzymes, leading to seizures and possibly death • Straightening/curling hair with treatments denatures proteins in hair causing hair to straighten or curl
Application of Denaturing Con’t • Curing meats or vegetables in vinegar – preserves food by denaturing enzymes in bacteria that cause food to spoil • Fruit and vegetables turn brown when exposed to air due to enzyme reactions: blanching fruit and veg (dipping quickly in boiling water) denatures enzymes that cause them to turn brown (or could squeeze lemon juice = acidic)