Unit 5: Inside the CellCh. 2:2 (pgs. 32-37)

Cell Parts & Their Jobs

Sizes & Shape of Cells• How big/small are cells?

– Vary (< ½ µm up to ~1 m)• smallest cells?

– bacteria

• largest cells?– eggs, nerve

• Are cells 3-D or 2-D?– 3-D

• What shapes are cells?– many different

Why is there a limit to cell growth?• to keep surface area to volume ratio high

• so diffusion can occur efficiently

•cell division–if keep same overall volume, smaller cells have more surface area compared to one large cell

•add folds or projections

How can the surface area to volume ratio be increased?

2 Main Types of Organisms• unicellular

–How many cells?•one

–How/where are cell processes carried out?

•all by/in the one cell

–examples?•bacteria, Amoeba, Paramecium, Euglena

•multicellular–How many cells?

• more than one

–How/where are cell processes carried out?

•cells specialize (÷ of labor)

–examples?•human, tree,

zebra, bird,

fish, grass,

mushroom

Why can multicellular organisms be big if cells need to be small?

Two Major Types of Cells• What are the two major types of cells?

– prokaryotes– eukaryotes (YOU-karyote!)

• similarities & differences?

both

*cell membrane*cytoplasm*ribosomes*DNA

Two Major Types of Cells

• examples?–prokaryotic

• bacteria–eukaryotic

• protists, fungi, plants, animals

Organization Within Eukaryotic Cells• Why might cells need

to be organized?– not efficient to

have all reactions happening in cytoplasm

• How are they organized???– contained by cell

membrane

– have organelles• with membranes

• do different jobs

cytoplasm

Eukaryotic Cell Organelles• plant & animal cells

1. *cell (plasma) membrane

2. *cytoplasm

3. nucleus

4. nuclear membrane (envelope)

5. nucleolus

6. *ribosome

7. endoplasmic reticulum

8. golgi bodies (apparatus)

9. mitochondrion

10.cytoskeleton

11.vacuole

12. lysosome

• plant cells1. chloroplast

2. *cell wall

• animal cells1. *cilia & flagella

2. centrioles

*These can also be found in prokaryotic cells.

CiliaFlagella

• Found in:– prokaryotic &

eukaryotic cells

• Functions:– boundary between cell &

its environment• surrounds cell

– acts as a gatekeeper• “selectively permeable”

• Looks like:– fence w/ gates (around cell)

Cell (Plasma) Membrane

Cytoplasm• Found in:

–prokaryotic & eukaryotic cells

• Functions:–organelles float in it–some chemical

reactions happen in it

• Looks like:–Jell-O

Nuclear Membrane (Envelope)• Found in:

– eukaryotic cells only

• Functions:– boundary between

nucleus & cytoplasm– acts as a gatekeeper

• “selectively permeable”

• Looks like:– fence w/ gates

(around nucleus)

Nucleus• Found in:

– eukaryotic cells only

• “floats” in cytoplasm

• Functions:– controls cell’s

activities

– contains DNA

• Looks like:– an eyeball

Chromatin & Chromosomes: Inside the Nucleus

• Found in:

– eukaryotic cells only

• Functions:– genetic information

– instructions for cell’s activities

• chromatin looks like:– spaghetti

• chromosomes look like:• X

Nucleolus: Inside the Nucleus

• Found in:– eukaryotic cells only

• Functions:– Makes ribosomes/

RNA (ribonucleic acid)

• Looks like: – iris (colored part) of

eyeball

nucleolus

nucleus

Ribosome• Found in:

– prokaryotic & eukaryotic cells

• Functions:– synthesizes (makes) proteins from amino acids

• Looks like:– pepper (dots)

• Found in:– eukaryotic cells only

• Functions:– transports (mostly) proteins

through cell

• SER looks like:– bubble-letter “H”

• RER looks like:– bubble-letter “H”

• with pepper (dots)– ribosomes

Smooth Endoplasmic Reticulum (SER) &Rough Endoplasmic Reticulum (RER)

Golgi Bodies (Apparatus)• Found in:

– eukaryotic cells only

• Functions:– packages, modifies

& exports proteins within cell & out of cell

• Looks like:– pancake stacks

• often w/ drips of syrup @ ends

Mitochondria• Found in:

– eukaryotic cells only

• Functions:– “power house” of the cell

• creates energy (ATP) through cellular respiration

• Looks like:– hot dog w/ mustard

Mighty Mitochondria

Why is the inner membrane highly

folded?

Cytoskeleton• Found in:

– eukaryotic cells only

• Functions:– shape & support– move organelles

• Looks like:– beams in a house

Vacuole• Found in:– eukaryotic cells only

• large vacuoles in plant cells• small vacuoles in animals cells

• Functions:– store water, food, waste– maintain turgor pressure in plants

• keeps cells “plump” & prevents wilting

– maintain osmotic balance• prevents cell from bursting

– contractile vacuole

• Looks like:– swimming pool Paramecium

Lysosome• Found in:

– eukaryotic cells only• primarily in animal cells

• Functions:– contains digestive

enzymes:• to breakdown:

– large food molecules– old, worn out cell parts

• Looks like:– stomach (w/ enzymes)

Lysosome animation

Chloroplast• Found in:

–eukaryotic cells only• plants (& some protists)

• Functions:–photosynthesis

• makes glucose & oxygen

• Looks like:–green solar panels

Chloroplast Cyclosis

Cell Wall• Found in:

– prokaryotes• bacteria

– some eukaryotes• plants• algae• fungi

• Functions:– protection– support

• Looks like:– wall, box

Cilia• Found in:

–eukaryotic cells• some animals

• some protozoa

• Functions:–movement

–sometimes sensing the environment

• Looks like:–fringes

Flagellum• Found in:

– many prokaryotic cells• bacteria

– some eukaryotic cells• some animals• some protozoa

• Functions:

– movement

– sometimes sensing the environment

• Looks like:– tail, whip

Centrioles• Found in:

–eukaryotic cells only• animals cells only

• Functions:–help in cell division

(mitosis)

• Looks like:–stacked logs

–salt & pepper shakers

Extras• ID eukaryotic animal cell organelles:

– http://www.wisc-online.com/Objects/ViewObject.aspx?ID=AP11604

• Cell Part ID interactive:– http://www.wisc-online.com/objects/

ViewObject.aspx?ID=AP11403

• Cell Organelles Game:– http://www.quia.com/mc/65947.html