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PROTEIN

PROTEIN. Protein Structure. Polymer of amino acids amine group (N) acid group side chain. Protein Structure. Proteins are unique among energy nutrients They contain NITROGEN Composed of 20 different amino acids 9 amino acids are essential, other 11 are not essential

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PROTEIN

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  1. PROTEIN

  2. Protein Structure • Polymer of amino acids • amine group (N) • acid group • side chain

  3. Protein Structure Proteins are unique among energy nutrients They contain NITROGEN Composed of 20 different amino acids 9 amino acids are essential, other 11 are not essential Proteins are strands of amino acids linked by a peptide bond with next amino acid

  4. Glucose Triglyceride

  5. Protein Structure Primary Structure Amino acid sequence or strand like a strand of pop-beads or pearls Secondary Structure coiling of the strand like a slinky: positive and negative parts attract each other

  6. Protein Structure Tertiary or third level of structure Folding back of coil The slinky gets messed up Quaternary or fourth level of structure Subunits fit together Hemoglobin has four subunits to make the functional molecule

  7. Protein Structure SHAPE DETERMINES FUNCTION The shape of the protein molecule determines if the molecule is functional the shape of the lipase molecule determines if it will actually help breakdown a lipid

  8. Protein Structure Change of shape is called DENATURATION What causes change of shape? acid (like the stomach low pH) or base(high pH) alcohol mechanical agitation(beating an egg white) heat(heat an egg white) or heavy metals(mercury)

  9. Denaturation

  10. Cellular Protein Synthesis DNA: in nucleus: acts as a template for mRNA mRNA moves out of nucleus to cytoplasm Carries instruction for an amino acid sequence for a specific protein to a ribosome Ribosome ‘reads’ the mRNA which dictates which amino acid is next tRNA carries the correct amino acid to the mRNA

  11. Cellular Protein Synthesis tRNA’s line up one after the other with amino acids Amino acids form peptide bonds to make the primary sequence of the protein Protein then coils to form the secondary and tertiary structure SHAPE DETERMINES FUNCTION

  12. How Are Proteins Made?

  13. Heredity Factor • Cystic fibrosis • Hypercholesterolemia • LDL-receptor • Sickle cell anemia

  14. Sickle-cell hemoglobin

  15. Protein Digestion Stomach Denaturation Pepsin induced breakdown into shorter ‘peptides’ Small Intestines duodenum: peptidases or proteases enter from pancreas thru the common bile duct breakdown proteins to aa’s, dipeptides and tripeptides

  16. Protein Digestion Cells of small intestine complete digestion of proteins so that only amino acids remain cells of S.I. absorb amino acids and a few larger peptides and release them into the blood for circulation

  17. Protein Function • Structure proteins • Muscle fiber protein • Connective proteins • others

  18. Protein: Function Supporting Growth and Maintenance body needs amino acids to grow new cells and replace cells that are worn out

  19. Protein: Function Building Enzymes, Hormones, and other Compounds amino acids used to make enzymes (e.g.. lipases for digestion) amino acids used to make some hormones(e.g.. insulin for glucose metabolism)

  20. Protein: Function Building Antibodies antibodies are formed from amino acids to defend against foreign proteins and substances in the body Maintaining fluid and electrolyte balance Proteins act like magnets and hold water in the blood vessels and also electrolytes like sodium

  21. Transport Proteins Cellular content differ from the contents of the surrounding environment: fluids and electrolytes Protein Membrane carriers provide a ‘pump’ to maintain this difference Sodium-Potassium Pump Animation of the Sodium-Potassium Pump

  22. Protein: Function Maintain acid-base balance proteins buffer the blood against big changes in pH so body remains pretty neutral .

  23. Protein: Function Providing Energy When insufficient CHO and Fat are eaten, the body takes apart Protein for energy Nitrogen portion removed from A.A. and the rest is oxidized for energy. Nitrogen ends up in the urine as urea

  24. Amino Acid Possibilities Can be added to other A.A.’s to make a protein Can have Nitrogen removed then it can be oxidized for energy or made into glucose (glucogenesis) or made into fat (lipogenesis) The diet needs to supply the 9 essential amino acids and 0.8 grams protein/kg wt.

  25. Protein Quality, Use and Need Protein Quality the amino acid assortment greatly influences a protein’s usefulness to the body

  26. Protein Quality, Use and Need Measuring Protein Quality the amount of the essential amino acids present in the protein If all are well represented, the protein will support growth and maintenance: COMPLETE PROTEIN If not, it won’t support growth: POOR QUALITY PROTEIN

  27. Protein quality Complete or good quality proteins soy beans, milk protein, animal flesh Poor quality proteins grains (missing lysine, an essential amino acid) many legumes(beans, missing methionine) Mutual Supplementation or complementing proteins mix grain and legume and get a good quality protein eg: corn tortilla and refried beans

  28. Vegetarian Diets-Reasons Health Religion Ethical Environmental Taste

  29. Types of Vegetarian Diets Non-red meat vegetarian poultry, fish, dairy, eggs O.K no special nutritional problems, may be high in fat, saturated fat Lacto-ovo vegetarian milk and eggs O.K. no special nutritional problems may be high in fat, saturated fat

  30. Vegetarian Diets: Types Strict Vegetarian: Vegan no animal products protein quality-complement calcium iron vitamin B 12 Top Stories - The Olympian - Olympia, Washington

  31. Vegetarian reduced risk obesity diabetes hypertension heart disease digestive disorders cancer Meat eaters growth support during critical times. Vegetarian vs Meat eaters

  32. Protein RDA: 0.8 grams/kg Nitrogen balance negative balance= more out in urine than coming in from the diet protein is being broken down faster than it is replaced who is in this predicament? elderly, bedridden

  33. Protein RDA: 0.8 grams/kg positive balance=more in the diet than going out in the urine protein is being made into tissue faster than it is taken apart

  34. Protein Rich Foods Animal products also high in vitamin B12, iron, and zinc lacking in vitamins C and folate often high in fat Legumes soy protein almost “complete” high in fiber, many B vitamins, iron, calcium low in vitamins A, C and B12

  35. Protein Needs 154# (70 kg) RDA = 70 x .8g/kg = 56 grams Athlete 1 to 1.5 g/kg (ADA)= 70 to 105 grams Protein/day

  36. Too little Protein Kwashiorkor: Protein deficiency true definition: what happens to the first child when the second child is born symptoms: edema, ascites(swollen belly) immune system failure so many infections loss of pigmentation Phenylalanine to Tyrosine to Melanin is blocked Fatty Liver no lipoproteins to carry fats and accumulate in liver

  37. Too Much Protein Dehydration 100 Cal of extra protein takes 350 grams(12 oz) of water to clear( this is how many grams of protein?) 100 Cal of extra CHO or Fat only takes 50 grams of water to clear Coupled with heavy workouts may result in dehydration

  38. Protein needs of Athletes May be up to 1.7 for power athletes May be up to 1.4 grams/kg for endurance athletes Tour de France, marathoners, triathletes They may need every available source of energy they can get their hands on

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