1. 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

2. 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?

3. 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)

4. Autotrophs
Autotrophs

5. 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

6. 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

7. 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.

8. 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

9. 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)

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

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

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

24. 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

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

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

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

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

29. 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

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

31. Human digestion
Epiglottis = flap of tissue that protects windpipe!

33. 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?

34. 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

35. 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

37. 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

38. 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.

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

40. 3. 4. 2. 1. 5. Stomach 2. Small intestine 3. Liver
4. Gall bladder 5. pancrease

41. 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

42. 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)?