Chapter 6 The Proteins and Amino Acids

1. Chapter 6The Proteins and Amino Acids Nutrition: Concepts & Controversies, 12e Sizer/Whitney

2. The Structure of Proteins • Difference from carbohydrates and fats • Amino acids • Carbon atom with amine group and acid group • Side chain • Essential amino acids • Conditionally essential • Recycling • Priority system

3. How Do Amino Acids Build Proteins? • Peptide bonds • Link amino acids • Strands of amino acids do not remain straight • Coils • Folds • Side chain electrical charge • Activation

4. The Coiling and Folding of a Protein Molecule

5. The Structure of Hemoglobin

6. Normal Red Blood Cells and Sickle Cells

7. Protein Synthesis

8. Denaturation of Proteins • Denaturing agents • Digestion • Stomach acid • Dangers of denaturation

9. Protein Digestion • Stomach • Denatures protein in food • Uncoil protein’s strands • Enzymes attack peptide bonds • Small intestine • Polypeptides • Further break down • Common misconceptions

10. A Dipeptide and Tripeptide

11. How Protein in Food Becomes Amino Acids in the Body

12. Amino Acid Absorption • Absorbed by cells of small intestine • Larger molecules • Hormones or allergens • Separate sites for absorption • Released into the bloodstream • Carried to the liver

13. The Importance of Protein • Amino acids must be continually available • Building of new proteins • Amino acids are needed each day • Protein turnover

14. Roles of Body Proteins • Regulation of gene expression • Providing structure and movement • Muscle tissue • Other structural proteins • Building enzymes, hormones, & other compounds • Building antibodies

15. Enzyme Action

16. Amino Acid Sequence of Human Insulin

17. Roles of Body Proteins • Transporting substances • Hemoglobin and lipoproteins • Maintaining fluid and electrolyte balance • Edema • Maintaining acid-base balance • Blood clotting • Providing energy and glucose

18. Proteins Transport Substances Into and Out of Cells

19. Amino Acids to Glucose • Protein can help maintain blood glucose levels • No storage compound for protein • Dismantle tissue proteins • Oversupply of amino acids • Remove amine group • Use of residues

20. Three Different Energy Sources

21. Amino Acids to Glucose • Fate of an amino acid • Cellular use • Build protein • Make a needed compound • Dismantle amino acid for component parts • Wasting of amino acids • Preventing waste

22. People Most Likely to Be Harmed by Amino Acid Supplements

23. How Much Protein Do People Really Need? • DRI • Depends on body size • Infants and growing children • Recommended intake • Vegetarians • Minimum amount • Upper limit • Body’s health • Quality

24. Nitrogen Balance • Nitrogen excreted as compared to nitrogen eaten • Levels in healthy adults • Variation in nitrogen balance • Positive balance • Examples • Negative balance • Examples

25. Which Foods Provide High Quality Protein? • High-quality proteins • Enough of all essential amino acids • Limiting amino acids • Complementary proteins • Mutual supplementation • Protein digestibility • Animal proteins • Legumes

26. A Legume