1. Proteins
Function
Structure
Denaturation

2. Proteins Functions Direct and control chemical reactions
Structural parts of cell
ex. Cell membrane
3. Transport of molecules
haemoglobin (O2 transport)

3. Proteins Function (cont’d) 4. Provide support and shape
Muscle/hair/nails…
5. Chemical Messengers
Hormones - insulin

4. Proteins
Structure
Macromolecule made up of smaller units called amino acids
made up of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulphur (S)

5. Protein Structure Amino Acids humans need 20 different a.a.’s
8 are essential amino acids (our body cannot make them – come from our food)

6. Protein Structure
Protein Structure involves 4 phases beginning with a polypeptide chain and ending with several chains connecting together
Primary Structure
Individual amino acids join together
Many a.a.’s join together to form a polypeptide chain

7. Protein Structure Secondary Structure
When a polypeptide chain grows beyond 30 amino acids, it begins to fold upon itself
Forms either a:
α-helix
β-sheet

8. Secondary Structure

9. Protein Structure Tertiary Structure
Increasing bonding, cause secondary structure to fold up on itself further
Forms a 3-D shape

10. Tertiary Structure

11. Protein Structure Quaternary Structure
2 or more polypeptide chains combine to finally form a functional protein

13. Protein Structure
Protein structure depends entirely on the order in which the amino acids come together.
Chemical bonds help molecules take and hold a specific shape

14. Protein formation
** the ultimate shape of the protein will determine its function in the cell/organism.

15. Protein Denaturation
Shapes of proteins are critical to their proper functioning
When the protein changes shape it becomes “denatured”
Protein loses its ability to perform its specific function

16. Protein Denaturation Conditions that denature a protein Heat:
Cooking, sunstroke, fever
pH change:
Stomach acid, perm
Radiation:
Sun (uv rays), x-rays, microwaves, cell phones?
Harsh chemicals:
Salt – tenderizes meat

17. Proteins
What to do now?
Text page 35, #5,-8
Summarize note/mind map