1. Chemical Structure of Proteins
Nitrogen – Carbon – Carbon (NCC)
Amino – Central & R - Carboxyl H N C R O OH
Amino group
Carboxyl (acid)
group

2. Protein Structure
Chain of amino acids (molecules) linked together like a necklace
Each has its own unique structure of amino acids
Some are polar
others are non-
polar

3. Protein Structure
Twenty Amino Acids exist and we will study this chart when we learn how our body builds proteins
Each has a different structure

4. Protein Structure (polypeptides)
Proteins are often chains of polypeptides (smaller versions, 1-50 unites)
Dipeptide formation dehydration

5. Dehydration/ Hydrolysis
/dehydrat.html

6. Protein Structure
These long chains of amino acids fold into different structures

8. Protein Structure
Primary structure (1*) = the sequence of amino acids
Secondary structure (2*) = regular repeating shapes (a helix or B pleated sheets) due to H-bonding along the backbone of the protein.
Tertiary structure (3*) = overall 3 dimensional shape mainly determined by interactions between R groups
Quaternary structure (4*) = association of 2 or more polypeptide chains

9. Protein Function Varies
Proteins play many important roles in the body (including muscle structure, hormones, antibodies, hemoglobin for carrying oxygen, other transport proteins for carrying molecules across cell membranes, toxins, and chemical messengers in the nervous system).

10. Enzymes: enable chemical reactions

11. Structural Proteins
Examples: collagen in your skin, ligaments, tendons, and bones. Hair and muscles have structural proteins as well.

12. Movement:
Actin and Myosin,
cillia flagella

13. Transport Proteins

14. Communication: signal proteins

15. Defense: Antibodies

16. Motor Proteins:
Within the cell

17. Intracellular junctions
Extracellular matrix

18. Answer the following questions where you answered your Do Now:
How many of the 20 amino acid molecules do you have in your set?
Can you name three different functions performed by proteins in your body?
Can you name some amino acids you have heard of before and indicate where you heard of them?
Which of the CHNOPS elements are contained in all amino acids? In addition, two important amino acids, methionine and cysteine, also contain ____ and can be phosphorylated.
To review, what is the major class of organic molecules described in this section?
What are the subunits or building blocks of this class of molecules?