STRUCTURE & FUNCTION OF CELLSLECTURE #15
MS. DAYHONORS BIOLOGY
CELL THEORY
CELL TYPESCELL TYPES
Three Basic types of cells include:
Animal Cell(Eukaryote)
Plant Cell(Eukaryote)
Bacterial Cell
(Prokaryote)
**SMALLEST
ALL CELLS…
Contain 4 basic cell structures:
Cell MembraneCytoplasmRibosomesDNA
**not an organelle
PROKARYOTES: PROKARYOTES: THE FIRST CELLSTHE FIRST CELLS
Simplest and smallest type of cellEx: bacteria
NO nucleus NO/FEW organelles1 Single, circular chromosome (piece of DNA)
PROKARYOTESPROKARYOTESNucleoid region (center) contains the DNA (NO nulceus)
Surrounded by cell membrane & cell wall
Contain ribosomes in their cytoplasm to make proteins
Has cilia for reproduction and flagella for movement
EUKARYOTESAll eukaryotic cells HAVE:a Nucleusmembrane-bound
organelles
These cell types (examples) includes:protistsfungiplantsanimals
More complex type of cells
THINK: “You carry a lot…of
stuff”
TWO MAIN TYPES OF EUKARYOTIC CELLS
Plant Cell
Animal Cell
ORGANELLESORGANELLESVery smallPerform various functions for cellMostly found in the cytoplasmMay or may not be membrane-
bound
BASIC ANIMAL BASIC ANIMAL CELL ORGANELLESCELL ORGANELLES
Nucleolus
Nucleus
Nuclear envelope
Ribosome (attached)Ribosome (free)
Cell Membrane
Rough endoplasmic reticulum
Golgi apparatus
Mitochondrion
Smooth endoplasmicreticulum
Centrioles
BASIC PLANT CELL BASIC PLANT CELL ORGANELLESORGANELLES
CELL OR PLASMA MEMBRANECELL OR PLASMA MEMBRANE(aka: phospholipid bilayer)(aka: phospholipid bilayer)
STRUCTURE Made of double layer (bilayer) of:
phospholipids and proteins Surrounds outside of ALL cellsFUNCTION (JOB) Controls what enters or leaves the cell
Outsideof cell
Insideof cell(cytoplasm)
Cellmembrane
Proteins
Proteinchannel Lipid bilayer
Carbohydratechains
CELL WALLCELL WALLSTRUCTURE• Found in:• plants
• Made of cellulose• Fungi
• Made of chitin• Bacteria
• Made of different sugar
• NOT IN ANIMAL CELLS!!!
FUNCTION (JOB)• Protect• Maintain shape
Cell wall
CYTOPLASM CYTOPLASM (aka: cytosol)(aka: cytosol)
STRUCTURE• Jelly-like substance• Mostly water
• aqueous solutionFUNCTION (JOB)• solution for chemical
reactions to take place in
• Holds organelles
cytoplasm
NUCLEUSNUCLEUSSTRUCTURE• Contains the DNA• Bounded by a
nuclear envelope (membrane) with pores
FUNCTION (JOB)• Controls the normal
activities of the cellNuclear
pores
NUCLEOLUS
STRUCTUREInside nucleusInside nucleusCell may have Cell may have 1 to 31 to 3DisappearsDisappears when cell when cell
dividesdividesFUNCTION (JOB)Makes ribosomes Makes ribosomes
(ribosomal subunits)(ribosomal subunits)
STRUCTURE Bean shapeDOUBLE membrane Has its own DNAFUNCTION “Powerhouse” of cell Makes cellular energy
(ATP) using CELLULAR RESPIRATION
MMITOCHONDRIONITOCHONDRION(PLURAL = MITOCHONDRIA)(PLURAL = MITOCHONDRIA)
CHLCHLOORROOPLASTSPLASTSSTRUCTUREBean shapeDOUBLE membraneHas its own DNA
FUNCTION (JOB)Found only in autotrophsCarries out
photosynthesis
RIBRIBOSOMESOSOMESSTRUCTUREMade of PROTEINS and rRNAThink: “RIB”s are meat; meat is protein
FUNCTION (JOB)Make proteins
Hooks amino acids to make proteinsProcess called TRANSLATION
RIBOSOMES (CON’T)RIBOSOMES (CON’T)
Can be attached or bound to
Rough ER
OR
Be free (unattached) in the
cytoplasm
ROUGH ENDOPLASMIC ROUGH ENDOPLASMIC RETICULUM (RER)RETICULUM (RER)
STRUCTUREHas ribosomes on
its surfaceFUNCTION (JOB) Helps to make
proteins for export out of cell
SMOOTH ENDOPLASMIC SMOOTH ENDOPLASMIC RETICULUM (SER)RETICULUM (SER)
STRUCTURENO ribosomes on its
surfaceUsually attached to
RERHollow tubesFUNCTION (JOB)Makes lipidsDestroys toxins (liver)
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GOLGI APPARATUS GOLGI APPARATUS (BODIES)(BODIES)
STRUCTUREStacks of flat sacs (NOT
CONNECTED!)Looks like pancakes with syrup drips“Pankcakes” NOT
connectedFUNCTION (JOB)• Modify• Sort• Package • Molecules for storage OR
transport in vesicles in vesicles
Transport vesicle
“syrup bubble”
CYTOSKELETONCYTOSKELETONSTRUCTURE Made of proteins Microfilaments are
threadlike Microtubules are tube-
like
FUNCTION (JOB) Help maintain cell shape Help move things around
cell
CENTRIOLESCENTRIOLES
STRUCTURE In animal cells ONLY Inside CENTROSOMES Paired structures near
nucleus (“t” shape”) Made of microtubules
FUNCTION (JOB) Appear during cell division Help pull chromosomes
apart
CENTRIOLES & THE MITOTIC SPINDLECENTRIOLES & THE MITOTIC SPINDLE
**Made of MICROTUBULES (Tubulin)
CILIA & FLAGELLACILIA & FLAGELLASTRUCTUREMade of
microtubules
Cilia Shorter more numerous
Flagella Longer fewer (usually 1-3)
CILIA & FLAGELLACILIA & FLAGELLAFUNCTION (JOB) of FlagellaMoves WHOLE cells
FUNCTION (JOB) of CiliaMoves fluids, gases or small particles across cell surface
LYSOLYSOSOMESSOMESSTRUCTURE They have a low pH
(acidic!) Contain Contain digestive digestive
enzymesenzymes
FUNCTION (JOB) Break down/recycle Break down/recycle
food, bacteria &food, bacteria & old old cell partscell parts
Think= “Think= “LysoLysol” l” cleanercleaner
(a) Phagocytosis: lysosome digesting food
1 µm
Lysosome containsactive hydrolytic
enzymes
Food vacuole fuses with lysosome
Hydrolyticenzymes digestfood particles
Digestion
Food vacuole
Plasma membraneLysosome
Digestiveenzymes
Lysosome
Nucleus
VACUOLESVACUOLESSTRUCTURESacks for storageSmall or absent in
animal cellsPlant cells have a
large Central Vacuole
No vacuoles in bacterial cells
STRUCTUREStorage for water,
food, wastes, enzymes, etc…
NOW…LET’S PRACTICE
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