Chapter 3Chapter 3

CellsCells

Cells and TissuesCells and Tissues

Carry out all chemical activities needed to Carry out all chemical activities needed to sustain lifesustain life

Cells are the building blocks of all living Cells are the building blocks of all living thingsthings

Tissues are groups of cells that are similar Tissues are groups of cells that are similar in structure and functionin structure and function

Anatomy of the CellAnatomy of the Cell

Cells are not all the sameCells are not all the same

All cells share general structuresAll cells share general structures

Cells are organized into three main Cells are organized into three main regionsregions– NucleusNucleus– CytoplasmCytoplasm– Plasma membranePlasma membrane

Figure 3.1a

The NucleusThe Nucleus

Control center of the Control center of the cellcell– Contains genetic Contains genetic

material (DNA)material (DNA)

Three regionsThree regions– Nuclear membraneNuclear membrane– NucleolusNucleolus– ChromatinChromatin

Figure 3.1b

Nuclear MembraneNuclear Membrane

Barrier of nucleusBarrier of nucleus

Consists of a double phospholipid Consists of a double phospholipid membranemembrane

Contain nuclear pores that allow for Contain nuclear pores that allow for exchange of material with the rest of the exchange of material with the rest of the cellcell

Plasma MembranePlasma Membrane

Figure 3.2

Plasma Membrane Plasma Membrane SpecializationsSpecializations

MicrovilliMicrovilli– Finger-like Finger-like

projections that projections that increase surface increase surface area for absorptionarea for absorption

Figure 3.3

Plasma Membrane Plasma Membrane SpecializationsSpecializations

Membrane junctionsMembrane junctions– Tight junctionsTight junctions– DesmosomesDesmosomes– Gap junctionsGap junctions

Figure 3.3

Plasma MembranePlasma Membrane

Barrier for cell contentsBarrier for cell contents

Double phospholipid layerDouble phospholipid layer– Hydrophilic headsHydrophilic heads– Hydrophobic tailsHydrophobic tails

Also contains protein, cholesterol, and Also contains protein, cholesterol, and glycoproteinsglycoproteins

MEMBRANE STRUCTURE ANIMATIONPRESS

TO PLAY

NucleoliNucleoli

Nucleus contains one or more nucleoliNucleus contains one or more nucleoli

Sites of ribosome productionSites of ribosome production– Ribosomes then migrate to the cytoplasm Ribosomes then migrate to the cytoplasm

through nuclear poresthrough nuclear pores

ChromatinChromatin

Composed of DNA and proteinComposed of DNA and protein

Scattered throughout the nucleusScattered throughout the nucleus

Chromatin condenses to form Chromatin condenses to form chromosomes when the cell divideschromosomes when the cell divides

CytoplasmCytoplasm

Material outside the nucleus and inside the Material outside the nucleus and inside the plasma membraneplasma membrane– CytosolCytosol

Fluid that suspends other elementsFluid that suspends other elements

– OrganellesOrganellesMetabolic machinery of the cellMetabolic machinery of the cell

– InclusionsInclusionsNon-functioning unitsNon-functioning units

Cytoplasmic OrganellesCytoplasmic Organelles

Figure 3.4

Cytoplasmic OrganellesCytoplasmic Organelles

RibosomesRibosomes– Made of protein and RNAMade of protein and RNA– Sites of protein synthesisSites of protein synthesis– Found at two locationsFound at two locations

Free in the cytoplasmFree in the cytoplasm

Attached to rough endoplasmic reticulumAttached to rough endoplasmic reticulum

Cytoplasmic OrganellesCytoplasmic Organelles

Endoplasmic reticulum (ER)Endoplasmic reticulum (ER)– Fluid-filled tubules for carrying substancesFluid-filled tubules for carrying substances– Two types of ERTwo types of ER

Rough Endoplasmic ReticulumRough Endoplasmic Reticulum– Studded with ribosomesStudded with ribosomes– Site where building materials of cellular membrane are formedSite where building materials of cellular membrane are formed

Smooth Endoplasmic ReticulumSmooth Endoplasmic Reticulum– Functions in cholesterol synthesis and breakdown, fat Functions in cholesterol synthesis and breakdown, fat

metabolism, and detoxification of drugsmetabolism, and detoxification of drugs

Cytoplasmic OrganellesCytoplasmic Organelles

Golgi apparatusGolgi apparatus– Modifies and packages proteinsModifies and packages proteins– Produces different types of packagesProduces different types of packages

Secretory vesiclesSecretory vesicles

Cell membrane componentsCell membrane components

LysosomesLysosomes

Golgi ApparatusGolgi Apparatus

Figure 3.6

Cytoplasmic OrganellesCytoplasmic Organelles

LysosomesLysosomes– Contain enzymes that digest nonusable Contain enzymes that digest nonusable

materials within the cellmaterials within the cell

PeroxisomesPeroxisomes– Membranous sacs of oxidase enzymesMembranous sacs of oxidase enzymes

Detoxify harmful substancesDetoxify harmful substancesBreak down free radicals Break down free radicals (highly reactive chemicals)(highly reactive chemicals)

– Replicate by pinching in halfReplicate by pinching in half

Cytoplasmic OrganellesCytoplasmic Organelles

MitochondriaMitochondria– ““Powerhouses” of the cellPowerhouses” of the cell– Change shape continuouslyChange shape continuously– Carry out reactions where oxygen is used to Carry out reactions where oxygen is used to

break down foodbreak down food– Provides ATP for cellular energyProvides ATP for cellular energy

Cytoplasmic OrganellesCytoplasmic Organelles

CytoskeletonCytoskeleton– Network of protein structures that extend Network of protein structures that extend

throughout the cytoplasmthroughout the cytoplasm– Provides the cell with an internal frameworkProvides the cell with an internal framework

Figure 3.7a

Cytoplasmic OrganellesCytoplasmic Organelles

CytoskeletonCytoskeleton– Three different typesThree different types

MicrofilamentsMicrofilaments

Intermediate Intermediate filamentsfilaments

MicrotubulesMicrotubules

Figure 3.7b–d

Cytoplasmic OrganellesCytoplasmic Organelles

CentriolesCentrioles– Rod-shaped bodies made of microtubulesRod-shaped bodies made of microtubules– Direct formation of mitotic spindle during cell Direct formation of mitotic spindle during cell

divisiondivision

Cellular ProjectionsCellular Projections

Not found in all cellsNot found in all cells

Used for movementUsed for movement– Cilia moves materials across the cell surfaceCilia moves materials across the cell surface– Flagellum propels the cellFlagellum propels the cell

Cell DiversityCell Diversity

Figure 3.8a–b

Cell DiversityCell Diversity

Figure 3.8c

Cell DiversityCell Diversity

Figure 3.8d–e

Cell DiversityCell Diversity

Figure 3.8f–g

Check PointCheck Point

Name the 4 elements that make up the bulk of Name the 4 elements that make up the bulk of living matter, and list 3 trace elements.living matter, and list 3 trace elements.

Define organelle and cell.Define organelle and cell.

List the structures of the nucleus, and explain List the structures of the nucleus, and explain the function of chromatin and nucleoli.the function of chromatin and nucleoli.

Identify the organelles of the cell describe the Identify the organelles of the cell describe the major function of each.major function of each.