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Unit 5: Inside the Cell
Ch. 2:2 (pgs. 32-37)
Cell Parts & Their Jobs
200
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
How can the surface area to
volume ratio be increased?
•cell division
–if keep same overall volume,
smaller cells have more surface
area compared to one large cell
•add folds or projections
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?
Prokaryotes
*No nucleus
(single strand
of DNA)
*No mitosis
*No membranebound organelles
both
*cell
membrane
*cytoplasm
*ribosomes
*DNA
Eukaryotes
*Nucleus
*Mitosis
*Membranebound
organelles
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
*These can also be found in prokaryotic 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
Cilia
11. vacuole
Flagella
12. lysosome
• plant cells
1. chloroplast
2. *cell wall
• animal cells
1. *cilia & flagella
2. centrioles
Cell (Plasma) Membrane
• 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)
Cytoplasm
• Found in:
– prokaryotic & eukaryotic cells
• Functions:
– organelles float in it
– some chemical reactions happen in it
• Looks like:
– Jell-O
• ~70% H2O
Nuclear Membrane (Envelope)
• Found in:
– eukaryotic cells only
• Functions:
– Surrounds nucleus
• 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
Inside the Nucleus:
Chromatin & Chromosomes
• Found in:
– eukaryotic cells only
• Functions:
– genetic information
– instructions for cell’s activities
• chromatin looks like:
– spaghetti
• chromosomes look like:
•X
Inside the Nucleus:
nucleolus
Nucleolus
• Found in:
– eukaryotic cells only
• Functions:
– makes ribosomes/
RNA (ribonucleic acid)
• Looks like:
– iris (colored part) of
eyeball
nucleus
• Found in:
Ribosome
–prokaryotic & eukaryotic cells
• Functions:
–synthesizes proteins from amino acids
• Looks like:
–pepper (dots)
• 1000s in cell
–can be:
» attached to (rough) endoplasmic reticulum
» free in cytoplasm
Smooth Endoplasmic Reticulum (SER) &
Rough Endoplasmic Reticulum (RER)
• 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
Golgi Bodies (Apparatus)
• Found in:
– eukaryotic cells only
• Functions:
– modifies, packages, &
exports proteins
within cell & out of cell
• Looks like:
– pancake stacks
• often w/ drips of syrup @ ends
Organelles Working Together:
How are cellular proteins produced, transported, & secreted?
Protein is:
1. synthesized by
ribosome
2. transported thru ER
3. modified & packaged
by Golgi body
4. exported (secreted)
out of cell when
vesicle fuses with
cell membrane &
releases it
(exocytosis)
Mitochondria
• Found in:
Mighty
Mitochondria
– eukaryotic cells only
• Functions:
– “power house” of the cell
• carries out cellular respiration
– releases energy (ATP) from glucose
• Looks like:
– hot dog w/ mustard
Why is the
inner
membrane
highly folded?
Cytoskeleton
• Found in:
– eukaryotic
cells only
• Functions:
– shape &
support
– move
organelles
• Looks like:
– beams in a
house
• Found in:
Vacuole
– eukaryotic cells only
• plant cells: large vacuole(s)
• animal cells: small vacuoles
• Functions:
– store water, food, waste
– maintain osmotic balance:
• large central vacuole in plants keeps cells “plump” &
prevents wilting
• contractile vacuole in many unicellular freshwater protists
• Looks like:
– swimming pool
Paramecium
Why
would
freshwater
protists
need to
pump out
water?
Lysosome animation
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)
Chloroplast Cyclosis
Chloroplast
• Found in:
–eukaryotic cells only
• plants (& some protists)
• Functions:
–photosynthesis
• makes glucose (food)
& oxygen
• Looks like:
–green solar panels
• Found in:
– prokaryotes
Cell Wall
• bacteria
– some eukaryotes
• plants
– made of cellulose
• algae
• fungi
• Functions:
– protection
– support
• Looks like:
– wall/box outside of
cell membrane
Cilia
Flagella & Cilia video
• Found in:
– eukaryotic cells
• some animals
• some protozoa
• Functions:
– Motility (movement)
• rowing, wave-like motion
– sometimes sensing the environment
• Looks like:
– fringes
Flagella & Cilia video
• Found in:
Flagellum
– many prokaryotic cells
• bacteria
– some eukaryotic cells
• some animals
• some protozoa
• Functions:
– motility (movement)
• whip-like motion
– sometimes sensing the environment
• Looks like:
– tail, whip
• Found in:
Centrioles
– eukaryotic cells only
• animal cells only
• Functions:
– help in cell division (mitosis)
• Looks like:
– stacked logs, spaghetti,
or 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