Cell Structure and Cell Structure and FunctionFunction

Chapter 4Chapter 4

Mid 1600s - Robert Hooke observed Mid 1600s - Robert Hooke observed

and described cells in corkand described cells in cork

Late 1600s - Antony van Late 1600s - Antony van

Leeuwenhoek observed sperm, Leeuwenhoek observed sperm,

microorganismsmicroorganisms

1820s - Robert Brown observed and 1820s - Robert Brown observed and

named nucleus in plant cellsnamed nucleus in plant cells

Early DiscoveriesEarly Discoveries

Hooke’s compound microscope & his drawings

Early MicroscopesEarly Microscopes

Do not post on Internet

Antony van Leeuwenhoek

Van LeeuwenhoekVan Leeuwenhoek

Do not post on Internet

Developing Cell TheoryDeveloping Cell Theory

Matthias Schleiden Matthias Schleiden

Theodor Schwann Theodor Schwann

Rudolf Virchow Rudolf Virchow

Cell TheoryCell Theory

1) Every organism is composed of one 1) Every organism is composed of one

or more cellsor more cells

2) Cell is smallest unit having 2) Cell is smallest unit having

properties of lifeproperties of life

3) Continuity of life arises from growth 3) Continuity of life arises from growth

and division of single cellsand division of single cells

Smallest unit of lifeSmallest unit of life

Can survive on its own or has Can survive on its own or has

potential to do sopotential to do so

Is highly organized for metabolismIs highly organized for metabolism

Senses and responds to environmentSenses and responds to environment

Has potential to reproduceHas potential to reproduce

CellCell

Question 1Question 1

1. What are three characteristics of 1. What are three characteristics of cells?cells?

Answer 1Answer 1

1. What are three characteristics of cells?1. What are three characteristics of cells? Smallest unit of lifeSmallest unit of life Can survive on its own or has potential to Can survive on its own or has potential to

do sodo so Is highly organized for metabolismIs highly organized for metabolism Senses and responds to environmentSenses and responds to environment Has potential to reproduceHas potential to reproduce

Question 2Question 2

2. What are two tenants of the cell 2. What are two tenants of the cell theory?theory?

Answer 2Answer 2

2. What are two tenants of the cell theory?2. What are two tenants of the cell theory?

1) Every organism is composed of one 1) Every organism is composed of one

or more cellsor more cells

2) Cell is smallest unit having 2) Cell is smallest unit having

properties of lifeproperties of life

3) Continuity of life arises from growth 3) Continuity of life arises from growth

and division of single cellsand division of single cells

Structure of CellsStructure of Cells

All start out life All start out life with:with:– Plasma Plasma

membrane membrane

– Region where Region where DNA is storedDNA is stored

– Cytoplasm Cytoplasm

Two types:Two types:– ProkaryoticProkaryotic

– Eukaryotic Eukaryotic

Main component of cell membranesMain component of cell membranes Gives the membrane its fluid Gives the membrane its fluid

propertiesproperties Two layers of phospholipidsTwo layers of phospholipids

Lipid BilayerLipid Bilayer

one layerof lipids

one layerof lipids

Figure 4.3Page 56

Membrane ProteinsMembrane Proteins

Protein pump across

bilayer

Protein channel

across bilayer

Protein pump

Recognition protein

Receptor protein

extracellular environment

cytoplasm

lipid bilayer

Figure 4.4Page 57

Androgen Insensitivity Syndrome Androgen Insensitivity Syndrome

Disease characteristics:Disease characteristics:   (AIS)   (AIS) typically includes evidence of typically includes evidence of feminization; and abnormal feminization; and abnormal secondary sexual development in secondary sexual development in puberty, and infertility. puberty, and infertility.

Cause:Cause: Gene for testosterone Gene for testosterone recognition malfunctions (recognition recognition malfunctions (recognition protein doesn’t work)protein doesn’t work)

““Genetic males” are feminizedGenetic males” are feminized

““Women with AIS look and feel like typical womenWomen with AIS look and feel like typical women, and in , and in every practical, social, legal, and everyday sense they are women, even every practical, social, legal, and everyday sense they are women, even though congenitally they have testes and XY chromosomes, and can never though congenitally they have testes and XY chromosomes, and can never bear children.  The fact that a "woman" has AIS and is genetically a "male" bear children.  The fact that a "woman" has AIS and is genetically a "male" is often not discovered until puberty, when she does not start to is often not discovered until puberty, when she does not start to menstruate and a gynecological examination reveals the syndrome.”menstruate and a gynecological examination reveals the syndrome.”

Beauty queen Janel Bishop, Miss Teen USA 1991, suffers from AIS.

http://transwoman.tripod.com/ais.htm

Plasma Membrane VideoPlasma Membrane Video

http://video.yahoo.com/video/play?http://video.yahoo.com/video/play?p=plasma+membrane&btn=Yahoop=plasma+membrane&btn=Yahoo%21+Search&tab=Video&ei=UTF-%21+Search&tab=Video&ei=UTF-8&b=0&oid=7cf76a19833e5a60&rurl=s8&b=0&oid=7cf76a19833e5a60&rurl=staff.jccc.net&vdone=http%3A%2Ftaff.jccc.net&vdone=http%3A%2F%2Fvideo.yahoo.com%2Fsearch%2Fvideo.yahoo.com%2Fsearch%2Fvideo%3Fp%3Dplasma%2Fvideo%3Fp%3Dplasma%2Bmembrane%26btn%3DYahoo%2Bmembrane%26btn%3DYahoo%2521%2BSearch%26tab%3DVideo%2521%2BSearch%26tab%3DVideo%26%26

Why Are Cells So Small?Why Are Cells So Small?

Surface-to-volume ratioSurface-to-volume ratio

The bigger a cell is, the less surface The bigger a cell is, the less surface

area there is per unit volumearea there is per unit volume

Above a certain size, material cannot Above a certain size, material cannot

be moved in or out of cell fast be moved in or out of cell fast

enoughenough

Question 3Question 3

3. What the two general cell types?3. What the two general cell types?

Answer 3Answer 3

3. What the two general cell types?3. What the two general cell types?

Two types:Two types:– ProkaryoticProkaryotic

– EukaryoticEukaryotic

Create detailed images of something Create detailed images of something

that is otherwise too small to seethat is otherwise too small to see

Light microscopesLight microscopes– Simple or compoundSimple or compound

Electron microscopesElectron microscopes– Transmission EM or Scanning EMTransmission EM or Scanning EM

MicroscopesMicroscopes

Limitations of Light MicroscopyLimitations of Light Microscopy

Wavelengths of light are 400-750 nmWavelengths of light are 400-750 nm

If a structure is less than one-half of a If a structure is less than one-half of a wavelength long, it will not be visiblewavelength long, it will not be visible

Light microscopes can resolve objects Light microscopes can resolve objects down to about 200 nm in sizedown to about 200 nm in size

Electron MicroscopyElectron Microscopy

Uses streams of accelerated Uses streams of accelerated electrons rather than lightelectrons rather than light

Electrons are focused by magnets Electrons are focused by magnets rather than glass lensesrather than glass lenses

Can resolve structures down to 0.5 Can resolve structures down to 0.5 nm nm

Eukaryotic CellsEukaryotic Cells

Have a nucleus and Have a nucleus and other organellesother organelles

Eukaryotic organismsEukaryotic organisms– PlantsPlants– AnimalsAnimals– ProtistansProtistans– FungiFungi

Animal Cell FeaturesAnimal Cell Features

Plasma Plasma membranemembrane

NucleusNucleus RibosomesRibosomes Endoplasmic Endoplasmic

reticulumreticulum Golgi bodyGolgi body VesiclesVesicles MitochondriaMitochondria CytoskeletonCytoskeleton

Figure 4.10bPage 61

Plant Cell FeaturesPlant Cell Features

Cell wallCell wall Central vacuoleCentral vacuole ChloroplastChloroplast

Plasma Plasma membranemembrane

NucleusNucleus RibosomesRibosomes Endoplasmic Endoplasmic

reticulumreticulum Golgi bodyGolgi body VesiclesVesicles MitochondriaMitochondria CytoskeletonCytoskeleton

Figure 4.10aPage 61

Keeps the DNA molecules of Keeps the DNA molecules of eukaryotic cells separated from eukaryotic cells separated from metabolic machinery of cytoplasmmetabolic machinery of cytoplasm

Makes it easier to organize DNA and Makes it easier to organize DNA and to copy it before parent cells divide to copy it before parent cells divide into daughter cells into daughter cells

Functions of NucleusFunctions of Nucleus

Components of NucleusComponents of Nucleus

nuclear envelope

nucleoplasm

nucleolus

chromatin

Figure 4.11bPage 62

Nuclear EnvelopeNuclear Envelope

Two outer membranes (lipid bilayers)Two outer membranes (lipid bilayers) Innermost surface has DNA attachment Innermost surface has DNA attachment

sitessites

Nuclear pore bilayer facing cytoplasm Nuclear envelope

bilayer facing nucleoplasm

Figure 4.12bPage 63

Group of related organelles in which Group of related organelles in which lipids are assembled and new lipids are assembled and new polypeptide chains are modifiedpolypeptide chains are modified

Products are sorted and shipped to Products are sorted and shipped to various destinationsvarious destinations

Cytomembrane SystemCytomembrane System

Components of Cytomembrane Components of Cytomembrane SystemSystem

Endoplasmic reticulumEndoplasmic reticulum

Golgi bodiesGolgi bodies

VesiclesVesicles

Endoplasmic ReticulumEndoplasmic Reticulum

In animal cells, continuous with In animal cells, continuous with

nuclear membranenuclear membrane

Extends throughout cytoplasmExtends throughout cytoplasm

Two regions - rough and smoothTwo regions - rough and smooth

Endoplasmic Reticulum VideoEndoplasmic Reticulum Video

Golgi BodyGolgi Body

Puts finishing touches on proteins Puts finishing touches on proteins and lipids that arrive from ERand lipids that arrive from ER

Packages finished material for Packages finished material for shipment to final destinationsshipment to final destinations

Material arrives and leaves in vesiclesMaterial arrives and leaves in vesicles

budding vesicle

Figure 4.15Page 65

Golgi Body VideoGolgi Body Video

http://www.biologymad.com/http://www.biologymad.com/resources/golgi.swfresources/golgi.swf

VesiclesVesicles

Membranous sacs that Membranous sacs that

move through move through

cytoplasmcytoplasm

LysosomesLysosomes

PeroxisomesPeroxisomes

LysosomesLysosomes

Lysosomes are membranous sacs of Lysosomes are membranous sacs of hydrolytic enzymes. hydrolytic enzymes.

Made by the endoplasmic reticulum Made by the endoplasmic reticulum and Golgi complex.and Golgi complex.

Formed by budding Golgi complex. Formed by budding Golgi complex.

Lysosomes recycle the cell's Lysosomes recycle the cell's organic material organic material auto-digestingauto-digesting

organellesorganelles

A Lysosomal DiseaseA Lysosomal Disease People with People with Gaucher diseaseGaucher disease lack the normal lack the normal

form of the glucocerebrosidase enzyme. form of the glucocerebrosidase enzyme. This This defect doesn’t allow macrophages to digest defect doesn’t allow macrophages to digest old, spent cellsold, spent cells..

These undigested cells accumulate and are These undigested cells accumulate and are “stored” in various parts of the body. Hence the “stored” in various parts of the body. Hence the name name “storage disease”.“storage disease”.

If the central nervous system is affected, death If the central nervous system is affected, death may ensue.may ensue.

Gaucher patients can receive enzyme Gaucher patients can receive enzyme replacement infusions. Not effective in the brain.replacement infusions. Not effective in the brain.

ATP-producing powerhousesATP-producing powerhouses

Membranes form two distinct Membranes form two distinct

compartments compartments

ATP-making machinery ATP-making machinery

embedded in inner mitochondrial embedded in inner mitochondrial

membranemembrane

MitochondriaMitochondria

Mitochondria VideoMitochondria Video

““Interactive Concepts in Biology” CDInteractive Concepts in Biology” CD Chapter 4Chapter 4

Mitochondrial OriginsMitochondrial Origins

Mitochondria resemble bacteriaMitochondria resemble bacteria

– Have own DNA, ribosomesHave own DNA, ribosomes

– Divide on their ownDivide on their own May have evolved from ancient May have evolved from ancient

bacteria that were engulfed but not bacteria that were engulfed but not digesteddigested

Mitochondrial DiseaseMitochondrial Disease MELASMELAS is an acronym for is an acronym for MMitochondrial itochondrial

myopathy, myopathy, EEncephalopathy, ncephalopathy, LLactic actic AAcidosis, cidosis, SStroke-like episodes. troke-like episodes.

Brain dysfunction (encephalopathy)Brain dysfunction (encephalopathy) Seizures and headachesSeizures and headaches Muscle disease with a build-up of lactic acid in the Muscle disease with a build-up of lactic acid in the

blood blood Temporary local paralysis (stroke-like episodes)Temporary local paralysis (stroke-like episodes) Abnormal thinking (dementia).Abnormal thinking (dementia). There is no known treatment for the underlying There is no known treatment for the underlying

diseasedisease

http://www.medicinenet.com/melas_syndrome/article.htm

PlastidsPlastids

Central VacuoleCentral Vacuole

Specialized Plant OrganellesSpecialized Plant Organelles

ChloroplastsChloroplasts

Convert sunlight energy to ATP Convert sunlight energy to ATP through photosynthesisthrough photosynthesis

CyclosisCyclosis

http://video.yahoo.com/video/play?http://video.yahoo.com/video/play?p=Chloroplasts&toggle=1&ei=UTF-p=Chloroplasts&toggle=1&ei=UTF-8&b=4&oid=806139b810acbda0&ru8&b=4&oid=806139b810acbda0&rurl=bio.winona.edu&vdone=http%3Arl=bio.winona.edu&vdone=http%3A%2F%2Fvideo.yahoo.com%2Fsearch%2F%2Fvideo.yahoo.com%2Fsearch%2Fvideo%3Fp%3DChloroplasts%2Fvideo%3Fp%3DChloroplasts%26toggle%3D1%26ei%3DUTF-%26toggle%3D1%26ei%3DUTF-8&vback=Results8&vback=Results

Other PlastidsOther Plastids

Chromoplasts Chromoplasts – No chlorophyllNo chlorophyll

– Abundance of carotenoidsAbundance of carotenoids

– Color fruits and flowers red to yellowColor fruits and flowers red to yellow

AmyloplastsAmyloplasts– No pigmentsNo pigments

– Store starchStore starch

Present in all eukaryotic cellsPresent in all eukaryotic cells

Basis for cell shape and internal Basis for cell shape and internal organizationorganization

Allows organelle movement within Allows organelle movement within cells and, in some cases, cell motilitycells and, in some cases, cell motility

CytoskeletonCytoskeleton

Cytoskeletal ElementsCytoskeletal Elements

microtubule

microfilament

intermediatefilament

MicrotubulesMicrotubules

Largest elementsLargest elements Composed of tubulinComposed of tubulin Arise from microtubule Arise from microtubule

organizing centers organizing centers

(MTOCs)(MTOCs) Involved in shape, motility, Involved in shape, motility,

cell divisioncell division

Figure 4.21Page 71

tubulinsubunit

Microtubule Formation VideoMicrotubule Formation Video

– http://video.yahoo.com/video/play?http://video.yahoo.com/video/play?p=microtubule&ei=UTF-p=microtubule&ei=UTF-8&b=5&oid=5ac35cab59185982&rurl=v8&b=5&oid=5ac35cab59185982&rurl=vethist.snu.ac.kr&vdone=http%3A%2Fethist.snu.ac.kr&vdone=http%3A%2F%2Fvideo.yahoo.com%2Fsearch%2Fvideo.yahoo.com%2Fsearch%2Fvideo%3Fp%3Dmicrotubule%26ei%2Fvideo%3Fp%3Dmicrotubule%26ei%3DUTF-8&vback=Results%3DUTF-8&vback=Results

MicrofilamentsMicrofilaments

Thinnest elementsThinnest elements

Composed of actin Composed of actin

Take part in Take part in

movement, formation, movement, formation,

and maintenance of and maintenance of

cell shapecell shapeactinsubunit

Figure 4.21Page 71

Intermediate FilamentsIntermediate Filaments

Only in animal Only in animal cells of certain cells of certain tissuestissues

Most stable Most stable cytoskeletal cytoskeletal elementselements

Six known Six known groupsgroups

onepolypeptidechain

Figure 4.21Page 71

Motor ProteinsMotor Proteins

KinesinsKinesins and and dyneinsdyneins move along move along

microtubulesmicrotubules

MyosinsMyosins move along microfilaments move along microfilaments

kinesin

microtubule

Figure 4.24b, Page 72

Motor ProteinsMotor Proteins

A motor is a device that consumes A motor is a device that consumes energy in one form and converts it energy in one form and converts it into motion (mechanical energy )into motion (mechanical energy )

Molecular motors convert the Molecular motors convert the chemical energy present in ATP into chemical energy present in ATP into mechanical energy mechanical energy

Motors are often superior to currently Motors are often superior to currently available man-made motors available man-made motors

http://en.wikipedia.org/wiki/Motor_protein

Kinesin (Stopped here 9/4 *biol)Kinesin (Stopped here 9/4 *biol)

http://fondazione-elba.org/nsito/abstract/37.htm

Question 4Question 4

4. Name three types of cytoskeletal 4. Name three types of cytoskeletal elements.elements.

Answer 4Answer 4

4. Name three types of cytoskeletal 4. Name three types of cytoskeletal elements.elements.

MicrotubulesMicrotubules MicrofilamentsMicrofilaments Intermediate filamentsIntermediate filaments

Question 5Question 5

5. What are two motor proteins and 5. What are two motor proteins and what do they do?what do they do?

Answer 5Answer 5

5. What are two motor proteins and 5. What are two motor proteins and what do they do?what do they do?

Kinesins and dyneins move along Kinesins and dyneins move along microtubulesmicrotubules

Myosins move along Myosins move along

microfilamentsmicrofilaments

Flagella and CiliaFlagella and Cilia

Structures for Structures for

cell motilitycell motility

9 + 2 internal 9 + 2 internal

structurestructure

dynein

microtubule

Figure 4.25Page 73

Flagella VideoFlagella Video

http://www.youtube.com/watch?http://www.youtube.com/watch?v=E1L27sUzwQ0v=E1L27sUzwQ0

Plant Cell WallsPlant Cell Walls

Primary cell wall

Secondary cell wall(3 layers)

Plant CuticlePlant Cuticle

Cell secretions and waxes Cell secretions and waxes accumulate at plant cell surfaceaccumulate at plant cell surface

SemitransparentSemitransparent

Restricts water lossRestricts water loss

Question 6Question 6

6. Name two organelles that plant 6. Name two organelles that plant cells have that animals don’t have.cells have that animals don’t have.

Answer 6Answer 6

6. Name two organelles that plant cells 6. Name two organelles that plant cells have that animals don’t have.have that animals don’t have.

Cell wallsCell walls

Plastids (chloroplasts, chromoplasts, Plastids (chloroplasts, chromoplasts,

and amyloplasts)and amyloplasts)

Central VacuoleCentral Vacuole

Matrixes between Animal CellsMatrixes between Animal Cells Animal cells have no cell wallsAnimal cells have no cell walls

Some are surrounded by a matrix Some are surrounded by a matrix

of cell secretions and other of cell secretions and other

materialmaterial

Cell-to-Cell JunctionsCell-to-Cell Junctions

Plants Plants

– Plasmodesmata Plasmodesmata Animals Animals

– Tight junctionsTight junctions

– Adhering Adhering junctionsjunctions

– Gap junctionsGap junctions

plasmodesma

Animal Cell JunctionsAnimal Cell Junctions

tightjunctions

adhering junction

gapjunction

Archaebacteria and EubacteriaArchaebacteria and Eubacteria

DNA is not enclosed in nucleusDNA is not enclosed in nucleus

Generally the smallest, simplest Generally the smallest, simplest

cellscells

No membrane-bound organellesNo membrane-bound organelles

Prokaryotic CellsProkaryotic Cells

Prokaryotic StructureProkaryotic Structure

DNA

pilus

flagellum

cytoplasm with ribosomes

capsulecell wall

plasma membrane