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•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?
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?
•What has to happen to large molecules before they can be used?
•Are undigestable materials considered nutrients?
Autotrophs vs. heterotrophsWhat is another name for autotrophs?How do they get their nutrients?
What are the two processes by which they can do this?
AutotrophsAutotrophs
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?
Autotrophs vs. heterotrophsWhich are the autotrophs?
heterotrophs?
Food intake patternsChunk feeders
Small food pieces or large?
What helps to physically break down food?
What helps to chemically break down food?
Examples?
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
Food intake patternsFilter feeders
How do they eat?What do they eat?Where do they
live?Do they move? If
so, how quickly?Examples?
Cells with flagella draw water through pores food particles are filtered out
What is digestion?Break down of
complex organic moleculesPolymers
monomers/ building blocks Why?
2 typesMechanical
Why?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
Digestion in HeterotrophsIntracellular vs. extracellular digestion
Where does digestion take place in each?
Amoeba•Intracellular or extracellular digestion?•How are wastes expelled?
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?
Rhizopus (bread mold)Intracellular or
extracellular digestion?
like other fungi secretes enzymes into food to digest then absorbs nutrients
HydraIntracellular or
extracellular digestion?
How do nutrients get to all of the Hydra’s cells?
EarthwormIntracellular or
extracellular digestion?
How do nutrients get to all of the earthworm’s cells?
HumanIntracellular or
extracellular digestion?
How do nutrients get to all of the human’s cells?
Venus’s-flytrapIs it a
producer? Or consumer?
How will the Venus flytrap digest this fly?
Digestion in AnimalsTwo-way trafficOne opening to body
Dead-end digestive system food enters & waste
exits same way (mouth)
Ex. HydraFood = Daphnia
(small crustacean)
Intra- or extracellular digestion?
Ex. Planaria Basal disc
Two openings to body/digestive tractTunnel-like digestive
system Mouth takes in food,
anus expels waste
Thorough, efficient digestion
complex multi-cellular animals
Ex. Earthworm, human, birds
One-way trafficDigestion in Animals
Physical vs. Chemical DigestionPhysical
Mechanical break down into smaller piecesincreases surface area for chemical digestionchewing (mouth), churning (stomach),
grinding (gizzard)
ChemicalEnzymes large molecules broken down into smaller moleculesCan then pass through the plasma membrane
Earthworm DigestionMouth – ingests & moistens foodPharynx – muscular contractions pull food from mouthEsophagus – muscular contractions push food to cropCrop – storage organGizzard – gravel & muscular contractions grind food to
small particlesIntestine – enzymes digest food into small molecules which
are absorbed through intestinal walls.Anus – expels undigested material or “castings"
What would happen if the earthworm had no gizzard???
How is the increased surface area of the intestine an adaptation?
Human nutrition & digestionComplex moleculesrequire digestion
proteinsfatscarbohydrates
Simple nutrients don’t require digestion… why not?vitaminsmineralswater
Old version New version
Human nutrition & digestion: food pyramids
Why is it important to eat a balanced diet?
Human nutrition & digestion
•See table 20.3 (summary of digestion in humans)•On pg 565 in textbook
Human Digestive System
Our own food breakdown factory!
Mouth– physical & chemical digestionWhy chew (mastication)???3 pairs of salivary glands secrete saliva
Moistens foodStarch digestion begins here
Starch salivary amylase maltose
(polysaccharide ) (disaccharide)
Human digestion
Pharynx & Esophagusperistalsis – alternating
contraction & relaxation of smooth muscle move food to stomach
Human digestion
Human digestionEpiglottis = flap of tissue that protects windpipe!
StomachPhysical digestion
churningChemical digestion of
protein beginsRelease of gastric juice
pepsin (enzyme) + hydrochloric acid break protein down into small polypeptides
Storagereleases chyme slowly
into small intestine (pH = 2)
Human digestion
•Why doesn’t your stomach digest itself???
•What is the function of rugae?
rugae
Pancreas Liver & gallbladdersecretes
pancreatic fluid containing enzymes:trypsin
proteins peptides
amylase starch maltose
lipase Lipids (fats)
fatty acids + glycerol
Liver produces bilebile stored in
gall bladder emulsifies fats
Human digestionAccessory Glands
Does food go through these organs (accessory glands?
Small intestineDigestion 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
Human digestion What is the purpose of villi? What do they “add” to the small intestine?
Large intestine (colon)Water & salts
reabsorbedSolid feces
formed & stored in rectum until eliminated through anus
anus
Human digestionWhy should you eat yogurt when you take antibiotics?
What can be dangerous about having diarrhea?
•How long is the small intestine?
•6.0 meters
•How long is the large intestine?
•1.5 meters
Human digestion
The earthwormLabel each part.What is the function of each part?
1.
3.
4. 2.
5.
1.2.
3. 4.
5.
6.
7.
8.
11.
13.
9.
10.
12.
Questions to ponderComment 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)?