1.1 Studying 1.1 Studying the the Structure of Structure of CellsCells

The Cell TheoryThe Cell Theory

The 3 main ideas areThe 3 main ideas are All living things are made of one or more All living things are made of one or more

cellscells The cell is the basic organizational unit of The cell is the basic organizational unit of

life.life. All cells come from pre-existing cells.All cells come from pre-existing cells.

All living things are made of cells. Our bodies are made up of between 10 trillion (1013) and 100 trillion (1014) cells.

A cell is the basic unit of life. Each contains smaller parts called organelles. These organelles have special functions that maintain all the life processes of the cell.

What is a Cell?What is a Cell?

nucleus nucleolus

smooth endoplasmicreticulum

ribosomes(small brown dots)

Golgi apparatus

mitochondrion

cell membrane

cell wall

central vacuole

cytoskeleton

wall of adjacent cell

chloroplast

cytoplasm

chromatin

Plant Cell

rough endoplasmicreticulum

Animal Cell

Cell WallCell Wall in plant cells, not animalin plant cells, not animal A tough, rigid structure lying just A tough, rigid structure lying just

outside a plant cell’s membraneoutside a plant cell’s membrane Provides support for the plant Provides support for the plant

cell and protection for the cell cell and protection for the cell organellesorganelles

Cell MembraneCell Membrane Separates the inside of the cell from the Separates the inside of the cell from the

external environmentexternal environment Controls the flow of materials into and out Controls the flow of materials into and out

of the cellof the cell

NucleusNucleus Brain of the cellBrain of the cell Controls all cell activitiesControls all cell activities Contains nearly all the Contains nearly all the

cellcell’’s DNA and with it, the s DNA and with it, the coded instructions for coded instructions for making PROTEINS and making PROTEINS and other important moleculesother important molecules

Nuclear membraneNuclear membrane Surrounds nucleusSurrounds nucleus Protects the contents of the nucleusProtects the contents of the nucleus Dotted with thousands of nuclear pores, that Dotted with thousands of nuclear pores, that

allow materials (such as ribosomes) in and outallow materials (such as ribosomes) in and out

Inside the nucleus we Inside the nucleus we see…see…

a granular material called…a granular material called… CHROMATINCHROMATIN

Chromatin= DNA + proteinChromatin= DNA + protein Usually spread out in nucleusUsually spread out in nucleus During cell division, chromatin clumps During cell division, chromatin clumps

together or condenses…we call this….together or condenses…we call this…. CHROMOSOMES CHROMOSOMES

ChromosomesChromosomes Threadlike structures that contain genetic Threadlike structures that contain genetic

information that is passed on from one information that is passed on from one generation to the nextgeneration to the next

NucleolusNucleolus Small dense region inside the nucleusSmall dense region inside the nucleus Function: makes ribosomesFunction: makes ribosomes

CytoplasmCytoplasm

jelly-like substance that fills the celljelly-like substance that fills the cell includes the cytosol (fluid), the organelles, and includes the cytosol (fluid), the organelles, and

other life-supporting materials, such as sugar other life-supporting materials, such as sugar and waterand water

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Endoplasmic reticulum Endoplasmic reticulum (ER)(ER) Connected to the nucleusConnected to the nucleus Network of membrane-Network of membrane-

covered channels that covered channels that transport materials made in transport materials made in the cellthe cell

2 types2 types Rough ER (has ribosomes on Rough ER (has ribosomes on

it)it) Smooth ER (no ribosomes)Smooth ER (no ribosomes)

RibosomesRibosomes

Helps to make proteinsHelps to make proteins PProteins make up much roteins make up much

of a cell’s structure and of a cell’s structure and are required for activities are required for activities necessary for the cell’s necessary for the cell’s survivalsurvival

Scattered throughout the Scattered throughout the cell cell

SSome float in the ome float in the cytoplasm, and others cytoplasm, and others

are attached to the ERare attached to the ER

Golgi Body (Apparatus)Golgi Body (Apparatus) Function: Function: modifiesmodifies, , sortssorts, and , and packagespackages proteins and proteins and

other materials from the ER for transport out of the other materials from the ER for transport out of the cellcell

VesiclesVesicles

Membrane-covered sacs that Membrane-covered sacs that transport materials inside the transport materials inside the cell and help these materials cell and help these materials cross the cell membrane to cross the cell membrane to enter or exit the cellenter or exit the cell

VacuolesVacuoles Sac-like organellesSac-like organelles Function: stores Function: stores

material such as material such as water, salts, proteins, water, salts, proteins, and carbohydratesand carbohydrates

Plant cells have a Plant cells have a single, large central single, large central vacuole, whereas vacuole, whereas animals may have animals may have several smaller several smaller vacuolesvacuoles

What is the one thing What is the one thing all living things need all living things need to eat, breathe, to eat, breathe, reproduce, move and reproduce, move and much more?much more?

ENERGY!!!!ENERGY!!!!

Two ways cells get Two ways cells get energy…energy…

from food molecules from food molecules from the (plants)from the (plants)

Mitochondria Mitochondria (singular: (singular: mitochondrion)mitochondrion) Convert chemical Convert chemical

energy stored in energy stored in glucose into glucose into compounds that are compounds that are more convenient for more convenient for the cell to usethe cell to use

Has 2 membranesHas 2 membranes Inner membraneInner membrane Outer membraneOuter membrane

ChloroplastsChloroplasts trap energy from the sun to make glucosetrap energy from the sun to make glucose

PHOTOSYNTHESISPHOTOSYNTHESIS 2 membranes2 membranes

CytoskeletonCytoskeleton Helps the cell maintain itsHelps the cell maintain itsstructure and provides “tracks” along which structure and provides “tracks” along which

vesicles and organelles can movevesicles and organelles can move 2 main parts2 main parts

MicrotubulesMicrotubules MicrofilamentsMicrofilaments

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