1. ~ Protein ~ Structure

2. Review: Protein Structures
Use the material provided to illustrate the 1°, 2°, 3° and 4° structures of protein. Keep in mind of the following terms:
   - alpha helix     - beta pleated sheet     - hydrogen bond     - disulfide bond     - carboxyl and amino group
5 minutes

3. identify each structure explain their reasoning
Go to another group and look at their model of protein structures to see if you can…
identify each structure
explain their reasoning
5 minutes

4. ~ Protein ~ Digestion & Absorption

5. Review
On the piece of paper provided draw a flow chart showing the process of protein digestion.
    - Name the reactants and products
    - Name the enzymes involved
    - Name the hormones involved minutes

7. Proenzymes or enzyme precursor or zymogen
Chemicals
Hormones
Pepsinogen
Pepsin
Trypsinogen
Trypsin
Proenzymes or enzyme precursor or zymogen
Protease
Proteolytic enzymes
Mucus
HCl IF
Denaturation:
HCl breaks the hydrogen and disulfide bonds, thus disrupts the 2°, 3°, 4° structures of protein making the peptide bonds available to the enzymes.
Gastrin
CCK
Secretin
Stomach
Intestine

10. Protein Absorption AA are absorbed in the lumen of the small intestine
Cross the membrane of enterocytes via active and passive transport
Then cross the basolateral membrane into the capillaries
AA circulate the blood stream to the liver

11. Food Allergies When larger peptides are absorbed
The immune system responds to them
Why is it that the majority of food allergies are caused by proteins?
Food Allergies are different from food intolerance which produces an nonimmunological reaction
The breakdown of proteins into amino acids is usually quite complete and typically results in the absorption of amino acids (not proteins) into the circulation. Sometimes, however, larger peptide chains are absorbed. When this happens, the body’s immune system may respond as if these peptides were dangerous. In such cases, the person is said to have an “allergic response,” or what is more commonly called a food allergy. Note, however, that not all adverse reactions to foods are true food allergies. A nonimmuneological reaction to a substance in a food is called a food intolerance (or food sensitivity). An example of a food intolerance is lactose intolerance.

12. Reading the Textbook Already read Structure: pg177-180 & pg183-187
Synthesis: based on class lecture
Genetics:
Today
Digestion & Absorption: pg
Function: pg

13. Homework Question
AAs with similar R-groups are transported by the same transport protein into the blood
Some experts recommend to avoid taking large quantities of certain amino acid supplements. Why?
If amino acids A & B have chemically similar R-groups, then taking amino acid A supplements would negatively affect the transportation rate of amino acid B because A and B are transported by the same carrier proteins. Meaning that you may be absorbing a lot of amino acid A (from the supplement), but not enough amino acid B.