Unit 9: Nutrition & Digestion ch. 20 In the first unit we talked about the characteristics of life…. Which characteristic relates to this unit? How do they get that energy? How do they get food? What do they do to it so that the nutrients can get into their cell(s)? •What about multicellular organisms??? How do nutrients get to all of their cells? In the first unit we talked about the characteristics of life…. Which characteristic would relate to this unit? That all living things require energy. How do they get that energy? From food How do they get food? Make it themselves or eat What do they do to it so that the nutrients can get into their cell(s)? Digest it What about multicellular organisms??? How do nutrients get to all of their cells? Nutrients are carried by blood in circulatory system

Nutrients – complex and simple substances required for life processes What is one major difference between large molecules (carbs, fats, & proteins) and small molecules (water, vitamins, & minerals? Complex substances need to be digested into smaller substances so that they can pass through cell membranes, but simple substances (water, vitamins, minerals) are already small enough to pass through cell membranes What has to happen to large molecules before they can be used? Need to be digested (broken down) Are undigestable materials considered nutrients? No b/c not usable by body Why is water important? For reactions taking place, part of blood, cooling body What is one major difference between large molecules (carbs, fats, & proteins) and small molecules (water, vitamins, & minerals? What has to happen to large molecules before they can be used? Are undigestable materials considered nutrients?

Autotrophs vs. heterotrophs What is another name for autotrophs? How do they get their nutrients? What are the two processes by which they can do this? What is another name for autotrophs? Producers How do they get their nutrients? Make own food What are the two processes by which they can do this? Chemosynthesis (Archaea) Photosynthesis (Protists, plants) What was the equation for p’syn again???? light 6CO2 + 6H2O ------------------ C6H12O6 + 6O2 chlorophyll (glucose)

Autotrophs Autotrophs

Autotrophs vs. heterotrophs Which are the autotrophs? heterotrophs? What is another name for heterotrophs? How do they get their nutrients? What are the categories that we can break heterotrophs into? What are 2 different food intake patterns? What is another name for heterotrophs? Consumers How do they get their nutrients? Must eat autotrophs or other heterotrophs What categories can we break heterotrophs into? Herbivores, Carnivores (including scavengers that feed on dead animals), decomposers (break down dead plants & animals & organic waste) What are 2 different food intake patterns? Chunk feeders & filter feeders

Food intake patterns Chunk feeders Small food pieces or large? What helps to physically break down food? What helps to chemically break down food? Examples? Small food pieces or large? Take in food in large pieces What helps to physically break down food? Require structures for physical/mechanical digestion, e.g., teeth, gizzard What helps to chemically break down food? Require enzymes to provide chemical digestion, e.g., amylase, pepsin, lactase Examples? Humans, hydra, earthworm, birds, hawks, sea anemones

Dentition & Diet specialized teeth include: Incisors- for cutting Canines- for tearing Premolars- for shredding Molars- for grinding type of teeth help determine diet of organism Teeth are found in the jaws of many vertebrates. The primary function of teeth is to tear and chew food so as to allow for digestion. Mammals have teeth of different sizes and shapes, a condition known as heterodonty, allowing different teeth to be specialized for different tasks.

Food intake patterns Filter feeders How do they eat? What do they eat? Where do they live? Do they move? If so, how quickly? Examples? How do you think they eat? Take water into body; filter out food; expel water What do you think they eat? Feed on microorganisms and/or nutrients floating in water Where do you think they live? In the water (oceans, lakes, etc.) Do they move? If so, how quickly? Sessile (stay in one place) or slow-moving Examples Include bivalves (clams, oysters, mussels) and baleen whales Cells with flagella draw water through pores  food particles are filtered out

What is digestion? Break down of complex organic molecules 2 types Polymers  monomers/ building blocks Why? 2 types Mechanical Chemical (involving enzymes)  series of hydrolysis reactions Organic Biological Macromolecule Polymer Monomer (building blocks) Function Carbohydrates (sugars, starches, cellulose) polysaccharide (such as starch & cellulose) monosaccharide (simple sugars such as glucose) Energy source, energy reserve, plant cell walls Lipids (fats, oils, & waxes) Not applicable Fatty acids & Glycerol (Built from 2 types of simpler molecules… NOT monomers.) Energy reserves, cell membrane, hormones, insulation, nerve transmission Protein Polypeptides Amino acids (20 different A.A.) Structure, enzymes, transport materials in & out of cells hormones, muscle Nucleic Acids (DNA & RNA) Polynucleotide (Nucleic Acids) Nucleotides (sugar-phosphate backbone & nitrogenous bases) Carries genetic code (“blueprint for organism) & directs protein synthesis Break down of complex organic molecules Polymers  monomers Why? So molecules can diffuse through cells’ membranes 2 types Mechanical  Why? increase surface area Chemical  involving enzymes  series of hydrolysis reactions water to break bonds between monomers (that made up the polymer)

Digestion in Heterotrophs Intracellular vs. extracellular digestion Where does digestion take place in each? Intracellular digestion – takes place inside a cell Extracellular digestion –large pieces of food are partially broken outside cells: sually extracellular digestion takes place in a digestive cavity surrounded by the body (stomach), or outside the organism entirely

Amoeba Intracellular or extracellular digestion? How are wastes expelled? Intracellular or extracellular digestion? Intracellular Endocytosis/phagocytosis… psuedopods form around food  Forms food vacuole  Lysosome fuses w/ food vacuole & releases enzymes to digest food… How are wastes expelled? exocytosis  vacuole w/ waste fuses w/ cell membrane & wastes are released into environment

Paramecium Intracellular or extracellular digestion? How does the food get to the oral groove? What forms around the food? How is it digested? How are wastes expelled? How does the food get to the oral groove? Action of cilia creates a current that draws food into oral groove What forms around the food? Food vacuole How is it digested? Lysosome fuses w/ food vacuole & releases enzymes to digest food… How are wastes expelled? Vacuole containing indigestible food fuses w/ an opening in the cell membrane called the anal pore… food waste is ejected from the cell through this pore

Rhizopus (bread mold) Intracellular or extracellular digestion? like other fungi secretes enzymes into food to digest then absorbs nutrients Intracellular or extracellular digestion? Extracellular WHERE? Outside of organism

Hydra Intracellular or extracellular digestion? How do nutrients get to all of the Hydra’s cells? Intracellular or extracellular digestion? BOTH… mostly extracellular (digestion starts in gastrovascular cavity), but some small pieces are taking into cells lining the cavity by phagocytosis & finish digestion within the cell (intracellular) How do nutrients get to all of the Hydra’s cells? b/c consists only of 2 layers of cells, digested food can diffuse readily to all of the animal’s other body cells… no 2 cells are far from a source of nutrients

Earthworm Intracellular or extracellular digestion? How do nutrients get to all of the earthworm’s cells? Intracellular or extracellular digestion? Extracellular How do nutrients get to all of the earthworm’s cells? Nutrients pass into bloodstream & are transported throughout body

Human Intracellular or extracellular digestion? How do nutrients get to all of the human’s cells? Intracellular or extracellular digestion? Extracellular How do nutrients get to all of the human’s cells? Nutrients pass into bloodstream & are transported throughout body

Venus’s-flytrap Is it a producer? Or consumer? How will the Venus flytrap digest this fly? Is it a producer? Or consumer? Technically a producer, but b/c it lives in soils that are low in nitrogen & other important nutrients it is also capable of digesting insects How will the Venus flytrap digest this fly? Extracellular digestion w/in cavity between “closed” leaves

Digestion in Animals Two-way traffic One opening to body Ex. Hydra Basal disc One opening to body Dead-end digestive system food enters & waste exits same way (mouth) Ex. Hydra Food = Daphnia (small crustacean) Intra- or extracellular digestion? Ex. Planaria

Digestion in Animals One-way traffic Two openings to body/digestive tract Tunnel-like digestive system Mouth takes in food, anus expels waste Thorough, efficient digestion complex multi-cellular animals Ex. Earthworm, human, birds Thorough, efficient digestion b/c food can still be going through digestion when another meal is eaten, also high surface area increase absorption of nutrients

Physical vs. Chemical Digestion Mechanical break down into smaller pieces increases surface area for chemical digestion chewing (mouth), churning (stomach), grinding (gizzard) Chemical Enzymes  large molecules broken down into smaller molecules Can then pass through the plasma membrane

Earthworm Digestion Mouth – ingests & moistens food What would happen if the earthworm had no gizzard??? Mouth – ingests & moistens food Pharynx – muscular contractions pull food from mouth Esophagus – muscular contractions push food to crop Crop – storage organ Gizzard – gravel & muscular contractions grind food to small particles Intestine – enzymes digest food into small molecules which are absorbed through intestinal walls. Anus – expels undigested material or “castings" Gizzard physical/mechanical digestion Intestine chemical digestion What would happen if the earthworm had no gizzard???? Digestion would begin in the intestine

How is the increased surface area of the intestine an adaptation? Helps to increase the absorption of nutrients

Human nutrition & digestion Complex molecules require digestion proteins fats carbohydrates Simple nutrients don’t require digestion… why not? vitamins minerals water

Human nutrition & digestion: food pyramids See new food pyramid info from kids health website Vegetarians have to eat certain combos of foods to obtain all amino acids (which are often gotten from meat) Old version New version

Human nutrition & digestion Why is it important to eat a balanced diet?

What problems can too much saturated fat cause What problems can too much saturated fat cause? Cardiovascular (heart) disease (ex. heart attack)

Human Digestive System See table 20.3 (summary of digestion in humans) On pg 565 in textbook

Our own food breakdown factory! Cartoon showing the digestive system as a factory

Human digestion Mouth– physical & chemical digestion Why chew (mastication)??? 3 pairs of salivary glands secrete saliva Moistens food Starch digestion begins here Starch salivary amylase maltose (polysaccharide ) (disaccharide) Teeth grind food into smaller pieces to increase surface area

Human digestion Pharynx & Esophagus peristalsis – alternating contraction & relaxation of smooth muscle move food to stomach

Human digestion Epiglottis = flap of tissue that protects windpipe!

Human digestion Stomach Physical digestion churning Chemical digestion of protein begins Release of gastric juice pepsin (enzyme) + hydrochloric acid break protein down into small polypeptides Storage releases chyme slowly into small intestine (pH = 2) rugae Why doesn’t your stomach digest itself??? Mucous layer protects stomach from digestion! What is the function of rugae? Help w/ mechanical/physical digestion Why doesn’t your stomach digest itself??? What is the function of rugae?

Human digestion Accessory Glands Pancreas Liver & gallbladder Does food go through these organs (accessory glands? Human digestion Accessory Glands Pancreas Liver & gallbladder secretes pancreatic fluid containing enzymes: trypsin proteins  peptides amylase starch  maltose lipase Lipids (fats)  fatty acids + glycerol Liver produces bile bile stored in gall bladder emulsifies fats

Human digestion Small intestine What is the purpose of villi? What do they “add” to the small intestine? Small intestine Digestion completed Starch digestion completed pancreatic amylase (enzyme) polysaccharides & disaccharides  monosaccharides Protein digestion completed trypsin (enzyme) polypeptides  amino acids Fats emulsified by bile digested by lipase (enzyme) Lipids  fatty acids & glycerol Nutrients absorbed thru walls of villi into bloodstream What is the purpose of villi? To increase surface area for the absorption of nutrients

Human digestion Large intestine (colon) Water & salts reabsorbed Why should you eat yogurt when you take antibiotics? What can be dangerous about having diarrhea? Human digestion Large intestine (colon) Water & salts reabsorbed Solid feces formed & stored in rectum until eliminated through anus anus

Human digestion How long is the small intestine? 6.0 meters How long is the large intestine? 1.5 meters Use lengths of string to mimic the length of the intestines.

The earthworm Label each part. What is the function of each part?

3. 4. 2. 1. 5. Stomach 2. Small intestine 3. Liver 4. Gall bladder 5. pancrease

1. 2. 3. 4. 5. 6. 7. 8. 11. 13. 9. 10. 12. Oral cavity (mouth) 2. Tongue 3. Salivary glands 4. Pharynx 5. Esophagus 6. Stomach 7. Small intestine 8. Liver 9. Gallbladder 10. Pancreas 11. Large intestine 12. Rectum 13. anus

Questions to ponder Comment on unity within diversity in relation to nutrition & digestion? How does form follow function? Think about surface area and the digestive system… Why the saying “you are what you eat?” What should you eat before a game or a run? What should you eat after weight-lifting? What foods should you avoid? What is the best way to maintain a healthy body composition (lean/fat balance, weight)?