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