•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)?