1. The Chemistry of Life Proteins
Ms. Richardson - SBI4U

2. Proteins - Overview
Involved in almost everything cells do
Includes enzymes, immunoglobulins, hemoglobin, keratin, fibrin, etc.
Proteins are made up of many amino acids (each is called a residue)

3. Amino Acids Proteins are made of one or more amino acids
The 20 amino acids differ in the R groups they contain (8 amino acids are essential)
These side chains can make the amino acid polar (hydrophilic), non-polar (hydrophobic), or charged (acidic/basic)
...when dissolved in water at a pH of 7, the ‘carboxyl’ donates an H+ ion to the ‘amino

4. Nonpolar Amino Acids

5. Polar Amino Acids

6. Acidic and Basic Amino Acids

7. Protein Structure Amino acids are the monomers that make up proteins
Amino acids are held together by peptide bonds which are formed by a dehydration synthesis reaction

8. Protein Structure Also called the conformation
There are four levels of structure/conformation
Depends on the amino acids it contains, and the interaction between those amino acids

9. Primary Structure
Polypeptide chain  many amino acids in a chain connected by peptide bonds
The sequence of amino acids is determined by the nucleotide sequence of a particular gene
In a protein with ‘X’ number of amino acids, number of possibilities is 20X

10. Secondary Structure Folding and coiling of amino acid chain
Formed by hydrogen bonds between oxygen atoms of a carboxyl group and hydrogen atoms of an amino group
Two types:
α helix – tight coil produced by H-bonds every 4 peptide bonds repeated
β pleated sheets – H-bonds formed between parallel stretches of a polypeptide

11. Tertiary Structure
The polypeptide chain undergoes additional folding due to side chain (R-group) interactions.

12. Quaternary Structure
Two or more polypeptide chains come together, such as in collagen and haemoglobin