1. Proteins and Amino Acids Chapter 6

2. #1 Amino Acids Are the Building Blocks of Protein Proteins are sequences of amino acids Types of amino acids Indispensable Dispensable Conditionally indispensable

3. #2 Amino Acids Are the Building Blocks of Proteins Amino acids are identified by their side groups

4. Amino Acids Are the Building Blocks of Proteins Protein Structure: Unique Three- Dimensional Shapes and Functions Amino-Acid Sequence Protein Shape

5. Amino Acids Are the Building Blocks of Proteins Protein Denaturation: Destabilizing a Protein’s Shape

6. Functions of Body Protein

7. Structural and Mechanical Functions Enzymes

8. #3 Essentiality of Amino Acids Essential – obtained in diet Non essential – body can synthesize Conditionally essential – body can normally synthesize unless under critical illness

9. Amino Acids

10. Peptide chains #4, 5

12. #6

13. #7 Functions of Body Proteins Hormones Immune Function Fluid Balance Acid–Base Balance

14. Proteins in the Body Protein synthesis Directed by cellular DNA Amino acid pool and protein turnover Synthesis of nonprotein molecules

15. Proteins in the Body Protein and nitrogen excretion Deamination of amino acids Amino groups converted to urea for excretion Nitrogen balance Nitrogen intake vs. nitrogen output

16. Functions of Body Proteins Transport Functions Sources of Energy and Glucose Courtesy of the USDA

17. Proteins Act as Carriers Lipoproteins have embedded proteins that help them transport fat and cholesterol in the blood.

18. Denaturation Heat, pH, oxidation, and mechanical agitation are some of the forces that can denature a protein, causing it to unfold and lose its functional shape.

19. Structural Proteins Proteins provide structure to all cells, including hair, skin, nails, and bone. As part of muscle, they transform energy into mechanical movement.

20. Hormones Hormones are formed in one part of the body and carried in the blood to a different location where they signal cells to alter activities.

21. Proteins and the Immune System Protein antibodies are a crucial line of defense against invading bacteria and viruses.

22. Proteins in the Blood Blood proteins attract fluid into capillaries. This counteracts the force of the heart beating, which pushes fluid out of capillaries.

23. #8-10 Protein Digestion and Absorption Stomach Proteins are denatured by hydrochloric acid Pepsin begins digestion Small intestine Pancreatic and intestinal proteases and peptidases complete digestion Amino acids are absorbed into the bloodstream

24. Protein Digestion

25. Protein Digestion and Absorption Amino Acid and Peptide Absorption

26. #11 Deamination All proteins are broken into amino acids To release energy from the amino acid, the body removes a nitrogen group The carbon skeleton is used for energy and can be used to make glucose. If our diet contains more protein than we need, it is sored as fat or used as glucose.

27. Hormone Actions

28. #12 Phases of Protein Synthesis Uniqueness of each person Amino acid sequences of proteins Genes – DNA Diet Adequate protein Essential amino acids

30. Protein Synthesis DNA template to make mRNA Transcription mRNA carries code to ribosome Ribosomes are protein factories mRNA specifies sequence of amino acids Translation tRNA Sequencing errors

31. #13 Protein (Nitrogen) Balance A pregnant woman adds protein so she has a positive nitrogen balance. A healthy person who is neither gaining nor losing nitrogen is in nitrogen equilibrium. A person who is severely ill and losing protein has a negative nitrogen balance.

32. #15 Proteins in the Diet Recommended protein intake Adult RDA = 0.8 grams/kilogram body weight Infant RDA = ~1.5 grams/kilogram body weight Physical stress, burns, wounds = can increase needs Protein consumption – excess in USA 2.2 Pounds per Kilogram

33. #15 Calculating our protein needs Convert weight to kilograms 2.2 Pounds per Kilogram A healthy adult needs 0.8 grams protein per kilogram Example Calculation: 145 lbs = 65.9 kg 65.9 kg x 0.8 g/kg = 52 grams protein needed per day

34. #16 Proteins in the Diet Protein quality Complete proteins Supply all essential amino acids Animal proteins, soy proteins Incomplete proteins Low in one or more essential amino acids Most plant proteins Complementary proteins Two incomplete proteins = complete protein © Photodisc

35. Proteins in the Diet Meat, eggs, milk, legumes, grains, and vegetables are all sources of protein. Fruits contain minimal amounts and, along with fats, are not considered protein sources. © Photodisc

36. #17 Vegetarian Diets Why people become vegetarians – religious, environmental, prevent animal cruelty, health benefits Types of vegetarians Lacto-ovo-vegetarian – eat dairy and eggs Semi-vegetarian Vegan – no animal products Health benefits vs. health risks Less fat, saturated fat, and cholesterol Restrictive diets may lack nutrients Careful planning needed for children, pregnant women

37. #17 Dietary Recommendations for Vegetarians Use complementary proteins to meet protein needs Soy is a complete protein Choose a variety of foods Choose whole, unrefined foods often Choose a variety of fruits and vegetables Choose lower fat dairy products, if used Use a regular source of vitamin B 12

38. The Health Effects of Too Little Protein #18, 19 Protein-energy malnutrition (PEM) Kwashiorkor Marasmus Nutritional Rehabilitation

39. #14,18 Protein Malnutrition Most Common during childhood in third world In USA: In poverty Older adults Hospitalized patients with anorexia nervosa, AIDA, cancer, malabsorption Can be corrected by a slow introduction of calories and protein and vitamin supplementation, fluids/electrolytes

40. #19 Marasmus withering or waste away Chronic Protein Energy Malnutrition Protein, energy and nutrients are inadequate No fat stores or muscle mass Growth stops Short and Thin Metabolism slows, temperature drops Hair is sparse and falls out Usually 6-18 months old who are fed diluted or improperly mixed formula

41. #19 Kwarshiorkor evil spirit that infects first child when second child is born  Breastfed until next child is born Baby is weaned and placed on a watered down version of family diet that is low in protein or not digested Lack of protein allows fluid to leak in tissues causing edema Dry flaky skin

42. The Health Effects of Too Much Protein #20

43. The Health Effects of Excess Protein #20 Excess Dietary Protein Kidney Function in those with renal issues Mineral Losses, Magnesium and Calcium Obesity Heart Disease Cancer Gout

44. #21 Protein and Amino acid supplements? Excess protein leads to excess body fat Intakes of calories and protein should match your exercise and weight goals No benefit to extra protein and causes excess nitrogen to be excreted which can lead to dehydration Amino acid supplement can interfere with absorption of other amino acids and cause neurotransmitter alterations

45. #22 Good sources of non-meat protein Soy protein – Tofu, soybeans Beans and rice Beans and corn Rice and black eyed peas Peanut butter on bread Pasta and beans