Chapter 6

1. Chapter 6 Proteins and Amino Acids

2. General Amino Acid Structure

3. Examples of amino acids

4. Condensation of two amino acids: Formation of a dipeptide

5. Formation of a Polypeptide

6. Folding and Shape of Proteins

8. Essential versus Non-essential Amino Acid Humans need ALL 20 amino acids to be able to make proteins. Glycine Alanine Serine Cysteine Proline Tyrosine Aspartic Acid Asparagine Glutamic Acid Glutamine Arginine Valine Leucine Isoleucine Threonine Methionine Phenylalanine Tryptophan Lysine Histidine Essential Amino Acids

9. Conditionally Essential Amino Acids

10. Protein digestion in the GI Tract Mouth - moisten and mechanical crushing Stomach - HCl denatures proteins - HCl also converts pepsinogen into pepsin - pepsin acts to cleave large polypeptides into smaller polypeptides

11. Protein digestion in the GI Tract Small Intestine - Trypsin and chymotrypsin breakdown polypeptides into smaller and smaller peptides. - Carboxypeptidases and aminopeptidases “chew” along from the ends to liberate amino acids. - Di- and tripeptidases break down dipeptides and tripeptides to amino acids. - Free amino acids are absorbed into the blood system.

12. Protein synthesis: Transcription Making messenger RNA Cell DNA mRNA

13. Protein synthesis: Translation Ribosomes “translate” the CODE of the message utilizing transfer RNAs which carry individual amino acids Ribosome mRNA Amino Acid Transfer RNA

14. Protein synthesis

15. Protein Function Within Our Body 1) Building materials (e.g. collagen, elastin, keratin, myocin, actin)

16. 2) Enzymes (e.g. lipase, amylase, pepsin)

17. 3) Hormones (e.g. insulin, glucagon, CCK)

18. 4) Regulators Fluid balance

19. 5) Transport: i.e. hemoglobin, ferritin Iron atom Heme

20. Normal versus Sickle Cells 6th residue Normal Hemoglobin Val-His-Leu-Thr-Pro-Glu-Glu- Sickle Cell Hemoglobin Val-His-Leu-Thr-Pro-Val-Glu-

21. A Membrane-bound transport protein “Sodium - Potassium Pump” INSIDE CELL OUTSIDE CELL

22. 6) Acid-Base Regulators Death 8.0 Alkalosis 7.45 Normal 7.35 Acidosis 6.8 Death

23. 7) Antibodies (Immune system) 8) Energy: - break down protein to use the energy.

24. Proteins per Serving In Food Groups Grams

25. Quality of Proteins • A COMPLETE protein contains essential amino acids is relatively the same amounts as humans need. • (e.g. meat, fish, poultry, eggs, milk) • However, all proteins do not have the same proportion of each amino acid.

26. © 2002 Wadsworth Publishing / Thomson Learning™

28. PEM (Protein-Energy Malnutrition) • affects 1 out of 4 children in the world. • accomplice in 50% of the 10.9 million child deaths each year. • 70% in Asia, 26% in Africa & 4% in Latin America

29. PEM (Marasmus) • chronic PEM • 6 - 18 months • inadequate intake of energy and protein.

30. PEM (Kwashiorkor) • acute PEM • sets in at 18 months - 2 years of age • inadequate intake of protein due to a change from breast milk to protein poor cereals.

31. Protein and Amino Acid Supplements • what is the RDA for protein? • what happens when more high protein higher amounts of proteins are consumed? • do athletes need to supplement their diet with higher amounts of protein or amino acid?

32. Types of Vegetarianism Omnivores - people that eat ALL foods including meat. Lactoovovegetarians - exclude meat, poultry, fish, and seafood. Lactovegetarians - also exclude eggs Vegan - exclude ALL animal derived foods

33. Vegetarians obtain their protein from whole grains, legumes, nuts, vegetables, and, in some cases, eggs and milk products

35. Food Pyramids Compared