2. Proteins Proteins contain the following elements: C, H, O, N, P, S Inorganic, or organic? Organic!!!

3. It’s alive! What’s so exciting about proteins? Proteins do it all: They’re structural (e.g. hair, fingernails, bones, etc). They act as messengers (hormones) They act as catalysts (enzymes)

4. Protein blocks: Proteins are made of building blocks called amino acids (you built these last week).

5. Amino Acids: Each amino acid contains the following: 1 carboxyl group (COOH) 1 amino group (NH 2 ) 1 hydrogen atom (H) 1 side chain, R, which is different in each amino acid

6. Amino acids continued… The side chain, or R, can be ANYTHING!!! The simplest amino acid, glycine, has a side chain that is simply a hydrogen atom. There are a total of 20 amino acids used by organisms, each with a different R.

7. Amino acid structure: C H N OH O R C H H Carboxyl group Amino group side chain

8. Making proteins… How can we combine amino acids together to form a more complicated molecule (protein)? Our old friend dehydration synthesis!!!

9. Dehydration Synthesis again?!?!? C H N OH O R C HH C H N O R C HH + Amino Acid+

10. Oh no…not again… C H N O R C HH C H N OH O R C H + H 2 O peptide bond Dipeptide + water

11. Di- = 2, many = ? We’ve seen a dipeptide, which is the combination of 2 amino acids. What would we call a chain of amino acids? A polypeptide!!! All proteins are made up of 1 or more polypeptide.

12. But I thought polypeptides were proteins… The smallest protein is insulin, a molecule composed of 51 amino acids linked together. Some proteins have over 100,000 amino acids though…

13. Proteins in depth: What makes the protein special is how the amino acids are arranged… number of amino acids order of amino acids If the protein gets overheated, the structure can break down called DENATURATION

14. Protein Structure