Test 2 Notes

Test 2 Notes - Test 2 NutriSci 10 Lecture Notes Outlines A...

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A. Proteins 1. What does it do? - Functions a. Building Material – growth, continual repair + turnover – we are made up of a lot of protein within bone, hair, fingernails, immune functions Lymphocytes – turn over rate 1 days skin – 13 to 120 days Intestinal cells –3 to 5 days red blood cells – 120 days cornea – turn over rate is 7 days brain, heart – many years b. Enzyme catalysis- causes 2 separate compounds to join together into a state of reduced energy and make a new compound is formed. c. Hormones are proteins or peptides Ex: Insulin, glucagon, epinephrine, gastrin, secretin, cholecytokinin (CCK); but not all hormones are protein like estrogen/testosterone d. Transporter Proteins – Electrolytes: charged particles, eg. Na, K, Cl – proteins are important for transporting a variety of different things like maintaining water balance e. Fluid Balance – inadequate protein in blood leads to edema (fluid leaks from blood vessels) – edema = sign of malnutrition f. Maintain acid-base balance – proteins are excellent buffers; help maintain blood pH. Really important for blood to stay neutral pH g. Immune Function – antibodies; lymphocytes (cells that kill invading microorganisms) = a cell that turns over really quickly h. Serves as an energy sources (4 kcal/g) (i) When glucose stores are low (if you’re hungry/starving) – protein is broken down to yield glucose (ii) If excess protein is eaten, the nitrogen is removed and carbon backbone is stored as glycogen or fat. i. Satiety – a state in which hunger is satisfied; person no longer desires to eat. Proteins prevent rebound hunger after a meal. 2. What is it? a. Proteins are chains of amino acids that contain C, H, O, N; = primary source of Nitrogen in our diets b. Components of Amino Acids = Nitrogen; side group varies c. Examples of amino acids i. Each amino acid has a specific chemical composition and properties ii. Important similarities in all amino acids d. 20 Amino Acids i. 9 Essential ones – we can’t make them; we require them in our diet ii. 11 non-essential ones – we can make them from other amino acids (we need to eat proteins to make other proteins) iii. We change the varying group from one amino acid to another iv. To make a dipepide (2 amino acids)- Take an acid group and amine group and H2O comes out to form a peptide bond; polypeptide = chain of amino acids v. Levels- Order of the amino acids (i) If we change some aspects of proteins (level of organization), the proteins don’t work right; in primary level, if we change one amino acid in the chain, we get a severe anemia (ii) Secondary order – S-S bonds – how the protein or peptide folds within itself (shape) (iii)Tertiary order – how the chain wraps around itself vi. Digestion of Dietary Protein (i) Stomach (1) HCl works on protein (2) The acid will help convert pepsinogen (inactive “proenzyme” to pepsin, which is active and will start digesting proteins)
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This note was uploaded on 04/02/2008 for the course NST 10 taught by Professor Amy during the Spring '08 term at Berkeley.

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Test 2 Notes - Test 2 NutriSci 10 Lecture Notes Outlines A...

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