Unit 14 Nutrition & Digestion ch. 20 300 Which characteristic of life 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? Which characteristic of life 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/absorb nutrients 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 What are nutrients? complex & simple substances required for life processes What must be done to large molecules (carbohydrates, fats, & proteins) that doesn’t need to be done small molecules (water, vitamins, & minerals)? Why? large molecules need to be digested (broken down) so they are small enough to diffuse through cell membranes What must be done to large molecules (carbohydrates, fats, & proteins) that doesn’t need to be done small molecules (water, vitamins, & minerals)? Why? Complex substances need to be digested (broken down) 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 Are undigestable materials considered nutrients? No b/c not usable by body Why is water important? For chemical reactions taking place, part of blood, cooling body Are indigestible materials considered nutrients? No, b/c not usable by body. Why is water important? for chemical reactions to take place, part of blood, cooling body

Autotrophs vs. heterotrophs What is another name for autotrophs? producers How do they get their nutrients? make their own food most by photosynthesis nutrient made = glucose 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 vs. heterotrophs Another name for heterotrophs? consumers How do they get nutrients? absorption ingestion (eating) What is another name for autotrophs? Producers How do they get their nutrients? Make own food SUGAR!!!!! 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) What categories can we break heterotrophs into? Herbivores, Carnivores (including scavengers that feed on dead animals), omnivores, decomposers (break down dead plants & animals & organic waste)

Autotrophs vs. heterotrophs Types of heterotrophs? herbivores (eat producers/plants) carnivores (eat consumers/meat) scavengers (feed on already dead animals) ex. vultures, buzzards, crabs omnivores (eat both plants & animals) decomposers (break down dead material & recycle nutrients) Must be part of EVERY ecosystem! What is another name for autotrophs? Producers How do they get their nutrients? Make own food SUGAR!!!!! 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)

Food intake patterns Chunk feeders Take in food in large pieces Require structures for physical/mechanical digestion ex. teeth, gizzard Require enzymes for chemical digestion Ex. amylase, pepsin, lactase Examples? Humans, hydra, birds, earthworm 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

Food intake patterns Filter feeders Generally sessile or slow-moving Take in water; filter out food (microorganisms and/or nutrients floating in water); expel water Examples bivalves (clams, oysters, mussels), whale shark, baleen whales Cells with flagella draw water through pores  food particles are filtered out 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

What is digestion? What is digestion? breakdown of complex organic molecules into simple molecules polymers  monomers/ building blocks Why is this necessary? so molecules can diffuse through cell membranes 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 simple “building block” 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 large molecules changed/broken down into DIFFERENT smaller molecules… these smaller molecules can then pass through the plasma membrane Ex. Proteins are chemically changed/broken down into polypeptides which are then chemically changed/broken down into amino acids

What are the 2 types of digestion? mechanical/physical (ex. chewing) chewing (mouth), churning (stomach), grinding (gizzard) to increase surface area & make chemical digestion faster chemical enzymes break large molecules (polymers) into smaller molecules (monomers) so can diffuse through cell membrane Mechanical physically breaks down food into smaller pieces  increases surface area for chemical digestion Ex. chewing = mastication (mouth), churning (stomach) Chemical Enzymes (chemicals that speed up chemical reactions)  large molecules changed/broken down into DIFFERENT smaller molecules… these smaller molecules can then pass through the plasma membrane Ex. Proteins are chemically changed/broken down into polypeptides which are then chemically changed/broken down into amino acids

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

Intracellular Digestion Paramecium Amoeba Endocytosis/phagocytosis… pseudopods 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 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 Amoeba

Extracellular Digestion Many have circulatory system to transport digested nutrients throughout body Digestion in environment & absorption of nutrients: Rhizopus (bread mold) secretes enzymes into food to digest (in environment) then absorbs nutrients Digestion in cavity within body (stomach) Many have circulatory system to transport digested nutrients throughout body Human Earthworm Bird grasshopper

Hydra Intracellular or extracellular digestion? BOTH! extracellular gastrovascular cavity intracellular small pieces taken into cells that line cavity by phagocytosis How do nutrients get to all of the Hydra’s cells? only 2 layers of cells, so digested food can diffuse readily to all cells… Intracellular or extracellular digestion? BOTH… mostly extracellular (digestion starts in gastrovascular cavity), but some small pieces are taken 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

Digestion in Heterotrophs Two-way traffic basal disc One opening to body food enters & waste exits same way (mouth) “dead-end” digestive system Examples Hydra Food = Daphnia Planaria Two way = materials can go in or out opening Two ways through opening

Digestion in Heterotrophs One-way traffic Two openings to body/digestive tract food enters & waste leaves through different openings (“tunnel”) mouth & anus thorough & efficient eat more while digesting complex multicellular animals ex. earthworm, bird, human, grasshopper 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 One way through opening

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 MPECGIA My pet earthworm can grow in April.

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

Human nutrition & digestion Examples of complex nutrients? proteins fats (lipids) carbohydrates Do complex nutrients require digestion? Why/why not? Yes, b/c too big to diffuse through cell membrane. Examples of simple nutrients? vitamins minerals water Do simple nutrients require digestion? Why/why not? No, b/c small enough to diffuse through cell membrane See new food pyramid info from kids health website Why is it important to eat a balanced diet? Get all nutrients you need. Vegetarians have to eat certain combos of foods to obtain all amino acids (which are often gotten from meat/protein) Calorie content Fats (lipids)  highest calorie (energy content) Carbs & proteins  about equal to each other; lower calorie count than fats

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

Human Digestive System See table 20.3 (summary of digestion in humans) On pg 565 in textbook Many People Eat Steak (&) Sweets Like Ravenous Animals

(polysaccharide ) (disaccharide) Human Digestion What type of digestion takes place in the mouth? mechanical/physical chewing increases surface area & speeds up chemical digestion chemical enzymes (starches  sugars) What does saliva do? moistens food contains enzymes Starch digestion begins in mouth. Teeth grind food into smaller pieces to increase surface area Bolus is the mass of moistened, chewed food Many People Eat Steak (&) Sweets Like Ravenous Animals enzyme (salivary amylase) starch maltose sugar (polysaccharide ) (disaccharide)

Human Digestion What do the pharynx & esophagus do? connect mouth to stomach How is food moved down esophagus? peristalsis alternating contraction & relaxation of smooth muscle move food to stomach Pharynx the part of the digestive and respiratory tracts situated between the cavity of the mouth and the esophagus Many People Eat Steak (&) Sweets Like Ravenous Animals

Human Digestion What is the epiglottis? flap of tissue that protects trachea (windpipe) while swallowing Many People Eat Steak (&) Sweets Like Ravenous Animals

peristalsis Many People Eat Steak (&) Sweets Like Ravenous Animals

Human Digestion What happens in the stomach? mechanical/physical digestion churning (muscle contractions) chemical digestion of protein (into smaller polypeptides begins) by gastric juices (enzyme = pepsin & hydrochloric acid) storage stomach slowly releases chyme (partially digested food) into small intestine (pH = 2) rugae chyme The thick semi-fluid mass of partly digested food that is passed from the stomach to the duodenum (beginning of the small intestine) pH =2 Why doesn’t your stomach digest itself??? Mucous layer protects stomach from digestion! What is the function of rugae? Help w/ mechanical/physical digestion Many People Eat Steak (&) Sweets Like Ravenous Animals What is the function of rugae? Help w/ mechanical digestion Why doesn’t your stomach digest itself???`

Human Digestion Accessory Glands Pancreas Liver & gallbladder Does food go through these organs (accessory glands? no Accessory Glands Pancreas Liver & gallbladder secretes pancreatic fluid containing enzymes into small intestine: trypsin proteins  peptides amylase starch  maltose lipase lipids (fats)  fatty acids + glycerol liver produces bile bile stored in gall bladder emulsifies fats breaks fats into tiny drops Many People Eat Steak (&) Sweets Like Ravenous Animals

Human Digestion Small intestine What is the purpose of villi? What do they “add” to the small intestine? Small intestine pancreatic enzymes & bile are added to chyme 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 villi into bloodstream What is the purpose of villi? To increase surface area for the absorption of nutrients In 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 How is structure related to function in the digestive system? Tube shape allows food to be taken in while other food is being digested and/or waste is being stored….. Long length & villi which increase surface area allows for maximum absorption of nutrients Use lengths of string to mimic the length of the intestines. How long is the small intestine? 6.0 meters How long is the large intestine? 1.5 meters Many People Eat Steak (&) Sweets Like Ravenous Animals How is structure related to function in the digestive system?

Many People Eat Steak (&) Sweets Like Ravenous Animals

Human Digestion What does the large intestine (colon) do? reabsorbs water & salts forms solid feces stored in rectum eliminated through anus Why should you eat yogurt when you take antibiotics? What can be dangerous about having diarrhea? Many People Eat Steak (&) Sweets Like Ravenous Animals 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.

Questions to ponder 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)?

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. pancreas

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 Many People Eat Steak (&) Sweets Like Ravenous Animals