1. Macromolecules – Day 1
PROTEINS

2. 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

3. EWW!

4. 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

5. 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

6. Diagram of Amino Acid Structure

7. 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

8. Diagram of a Protein (polypeptide):
CYSTEINE
LEUCINE
SERINE
LYSINE
Peptide Bond
Amino Acid (monomer)

9. 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

11. HORMONES Type of protein that acts as a chemical messenger
E.g. insulin – regulates blood sugar levels
E.g. Human growth hormone (HGH)

12. 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

13. 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

14. 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

15. 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)