1. 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

2. 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

3. 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)

4. 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)

5. 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)

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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.

17. 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

18. 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

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

20. Human Digestive System
See table 20.3 (summary of digestion in humans)
On pg 565 in textbook
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21. (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
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enzyme (salivary amylase)
starch maltose sugar
(polysaccharide ) (disaccharide)

22. 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
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23. Human Digestion What is the epiglottis?
flap of tissue that protects trachea (windpipe) while swallowing
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24. peristalsis
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25. 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
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What is the function of rugae?
Help w/ mechanical digestion
Why doesn’t your stomach digest itself???`

26. 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
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27. 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? meters How long is the large intestine? meters
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How is structure related to function in the digestive system?

28. Many People Eat Steak (&) Sweets Like Ravenous Animals

29. 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?
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anus

30. 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.

31. 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)?

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

33. 3. 4. 2. 1. 5. Stomach 2. Small intestine 3. Liver
4. Gall bladder 5. pancreas

34. 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
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