Part 2: Food, Energy, Temperature

Transcription

1 Part 2: Food, Energy, Temperature Chapter 5: Nutri:on, Feeding, Diges:on What is nutri.on? Study of how organisms use external sources to synthesize chemicals that make up their bodies How bodies convert food into energy for cell growth and repair Nutri.on Study of how organisms use external sources to synthesize chemicals that make up their bodies Nutrients that provide energy: Proteins Lipids Carbohydrates 4. Vitamins 5. Minerals Rela.ve amounts of 5 main chemicals in average human Nutri.on Study of how organisms use external sources to synthesize chemicals that make up their bodies Nutrients that provide energy: Rela.ve amounts of 5 main chemicals in average human Proteins Lipids Carbohydrates 4. Vitamins 5. Minerals Protein Made up of amino acids linked with pep.de bonds Polypep.des (short strings) Dipep.des (2 amino acids) Tripep.des (3 amino acids) Sequence of amino acids determines protein shape and func.on 1

2 1/5/15 Protein func.on Speed and regulate biochemical reac.ons Enzymes Fuel locomo.on (muscles) Determine structure of.ssues (collagen, kera.n) 4. Control cell membrane func.on and/or permeability Protein challenges Nitrogen is required for protein synthesis, but is limi.ng in most ecosystems N fixers convert N to useable form Channels, receptors 5. Transport oxygen (hemoglobin and myoglobin) 6. An.bodies Protein challenges Nitrogen is required for protein synthesis, but is limi.ng in most ecosystems Protein challenges amino acids 9-10 essen:al amino necessary for cell acids must be ingested func.ons, but we can t Non- essen:al synthesize all of them N fixers convert N to useable form Complex structure Timing of inges.on Not as important as previously thought Nutri.on Lipids Study of how organisms use external sources to synthesize chemicals that make up their bodies Nutrients that provide amino acids can be synthesized Condi.onally non- essen.al à synthesized under normal metabolic condi.ons energy: Proteins Lipids Carbohydrates Vitamins Minerals Waxes, phospholipids, sterols Triglycerides: fats, oils Most are fa_y acids Hydrocarbon chains Degree of satura.on and posi.on of double bond defines func.on Saturated all single bonds Unsaturated 1 double bond Polyunsaturated 2+ double bonds Rela.ve amounts of 5 main chemicals in average human 2

3 Lipid func.ons Main component of cell membrane Lipid func.ons Controls permeability of cell membrane Slows evapora.ve water loss Allows animals to live on land Storage compound Used for energy Lipid func.ons Lipids Synthesized from ingested carbohydrates and proteins Store excess as body fat This is how we can gain body fat from ea.ng sugar Naming based on posi.on of double bonds Essen:al faey acids can t be synthesized Omega- 3 and Omega- 6 Nutri.on Study of how organisms use external sources to synthesize chemicals that make up their bodies Nutrients that provide energy: Proteins Lipids Carbohydrates 4. Vitamins 5. Minerals Carbohydrates Sugars are easy to obtain Monosaccharide (fructose, glucose) Disaccharides (Sucrose) Polysaccharide (cellulose, starch) Easy to synthesize (from proteins, lipids) Rela.ve amounts of 5 main chemicals in average human 3

4 1/5/15 Nutri.on Carbohydrate diversity defines func.on Study of how organisms use external sources to synthesize chemicals that make up their bodies Nutrients that Structural support and shape Chi.n, cellulose Storage Starch, glycogen Energy source CNS, ATP produc.on 4. Transport Glucose (blood sugar) Brings stored compounds to area where used provide energy: Proteins Lipids Carbohydrates Vitamins Minerals Rela.ve amounts of 5 main chemicals in average human Vitamins Minerals Organic compounds required in small amounts None can be synthesized Various dietary sources for different vitamins Serve MANY physiological needs!! Elements that occur in enzymes and other proteins not found in cell cytoplasm Iodine for thyroid func.on Phosphorous to synthesize lipids, nucleic acids, and bone 40% of proteins are metalloproteins The great Serenge. migra.on: A quest for minerals? Wildebeests and zebras migrate 100+ miles every year Soils of SE are rich in necessary minerals Ca for lata.ng P and Na for developing young Video 4

5 1/5/15 Behavioral selec.on based on nutri.onal needs Feeding Process of obtaining and inges.ng food Three main considera.ons Wolf spiders preferen.ally select flies to balance their intake of protein and lipid Nutri.onal needs Feeding mechanisms How individuals acquire nutri.onal needs Feeding apparatus Ability to process nutrients Feeding Feeding mechanisms Process of obtaining and inges.ng food Three main considera.ons Mechanism.ed to feeding apparatus 3 main mechanisms of feeding Nutri.onal needs Feeding mechanisms Target and ingest individuals Suspension feeding Symbio.c microbes How individuals acquire nutri.onal needs Feeding apparatus Ability to process nutrients Feeding: Individual food items Apparatus Carnivores à teeth Birds à bills Subtle differences in apparatus allow exploita.on of different food items Bill shape allows feeding on different seed types Grazers tooth/jaw/lips allow feeding on different plants Feeding: Suspension feeding Baleen whales, blue whales, whale sharks feed on suspended objects Challenge: Gemng enough food!! Most are generalists Small but numerous prey Eat lower on food chain Greater E per unit.me VIDEO 5

6 Feeding: Suspension feeding Suspension feeders use variety of mechanisms Filter feeders: Baleen whale Feeding: Symbio.c microbes Foregut and Hindgut fermenta.on We ll come back to this... VIDEO1 Diges.on and Absorp.on Diges.on: Breakdown of food by enzymes and distribu.on of component chemicals to body.ssues PROTEINS AMINO ACIDS Absorp.on: Molecules broken down in diges.on enter living.ssues VARIOUS CELLULAR PROCESSES Headgut Foregut Midgut 4. Hindgut Headgut: Mouth, teeth, etc Capture/engulf food Prepare food for diges.on Feeding apparatus 6

7 Headgut Foregut Esophagus: moves food to stomach Stomach: ini.ates protein diges.on; stores and breaks down food Muscles, acids, diges.ve enzymes aid breakdown Headgut Foregut Midgut: Small intes:ne Diges.on of most proteins, lipids, and carbohydrates Absorp.on across cell membranes via microvilli Headgut Foregut Midgut 4. Hindgut: Large intes.ne Stores waste products Completes absorp.on Headgut Foregut Midgut 4. Hindgut 5. Pancreas Stomach acids trigger produc.on and secre.on of diges.ve enzymes Headgut Foregut Midgut 4. Hindgut 5. Pancreas 6. Liver Produces and secretes bile to digest lipids 7

8 Feeding: Fermenta.ve breakdown Herbivores Diges.on begins in 4- chambered stomachs Fermenters have long intes.nes Mammals don t produce cellulase Feeding: Fermenta.ve breakdown Fermenta.on: Enzyme- catalyzed reac.ons that occur without oxygen Anaerobic microbes (fermenters) thrive in gut lumen Aid in breakdown of cellulose Feeding: Fermenta.ve breakdown Fermenta.on based on where microbes live: Foregut fermenters Herbivores: Sheep, ca_le, antelope, deer Hindgut fermenters Rabbits, horses, ostriches, chickens, lizards, turtles Foregut fermenta.on: Microbe func.ons Produce cellulase (enzyme that breaks down cellulose) Synthesize B vitamins and essen.al amino acids Remember, we (and herbivores) can t make these Recycle waste products Microbes breakdown urea and use products (NH 3 ) to synthesize proteins Cellulose SCFAs, CO 2, CH 4 N in Urea NH 3 Proteins, amino acids Hindgut fermenta.on: Microbe func.ons Same func.ons, but in enlarged hindgut Cecum or colon Fermenta.on occurs aqer moving through stomach and small intes.ne...? Waste products of fermenta.on (proteins) must be eaten again N in Urea NH 3 Proteins, amino acids 8

9 Diges.on and absorp.on Nutri.onal value of food is only as good as your ability to digest and absorb the food Diges.on on it s own isn t enough! Diges.ve enzymes Produced throughout Diges.on process catalyzed by diges:ve enzymes Diges.ve enzymes Specific to type of bond they can break Lactase enzyme breaks bonds in lactose molecules People who don t produce lactase can t break down lactose Diges.ve enzymes Specific to type of nutrient they breakdown Carbohydrate diges.on: disaccharidases Protein diges.on: pep.dases Lipid diges.on: lipases, bile salts Diges.ve enzymes Proteins are so diverse, a single protein may require up to three enzymes to break down! 9

10 Absorp.on Transport of chemicals across epithelial cells in Greater surface area à faster absorp.on Microvilli on intes.nal lumen Can occur via simple diffusion, facilitated diffusion, or 2 ac.ve transport (requires E) Depends on solubility of molecule Nutri.onal responses at all.me scales Time scale Response(s) Example ACUTE Secrete diges.ve enzymes, acids GI tract func.on aqer a meal CHRONIC EVOLUTIONARY Dietary changes can alter amount/type of diges.ve enzyme Can alter nutri.onal value of food (more/less available) Individuals or popula.ons altered gene expression New field of NUTRITIONAL GENOMICS Low carb diets à reduce produc.on of carb- diges.ng enzymes Size of GI tract expand/contract based on species requirement Diet- regulated genes (Type II diabetes) Hummingbirds produce more sucrase DEVELOPMENTAL Genes expression turned on/off Lactose aqer weaning BIOLOGICAL CLOCK Daily/seasonal changes in enzyme produc.on Rats - more disaccharidases at night (nocturnal ea.ng) Seasonal fa_ening of migra.ng birds 10