unit 5: inside the cell ch. 2:2 (pgs. 32-37) cell parts & their jobs
TRANSCRIPT
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