04 Lecture Presentation Cells

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Copyright 2009 Pearson Education, Inc.

PowerPoint Lectures for

Biology: Concepts & Connections, Sixth EditionCampbell, Reece, Taylor, Simon, and Dickey

Chapter 4 A Tour of the Cell

Lecture by Richard L. MyersEdited by: Mr. Glen R. Mangali


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You should be able to

1. Describe the structure of cell membranes and howmembrane structure relates to function

2. Discuss ways that cellular organelles are involved in

the manufacture and breakdown of important cellularmolecules



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You should be able to

3. Describe cell structures involved in manufactureand breakdown of important cellular materials

4. Describe the function of each cellular organelle

that is involved in manufacture and breakdown ofimportant cellular materials

5. Describe the function of each cellular organelle

that is involved in energy conversion6. Describe the function of each cellular organelle

that is involved in internal and external support ofthe cell



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Introduction: Cells on the Move

Cells, the simplest collection ofmatter that can live, were firstobserved by Robert Hooke in1665

Antoni van Leeuwenhoek laterdescribed cells that could move

He viewed bacteria with his ownhand-crafted microscopes



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Introduction: Cells on the Move

Although cell movementattracted the earlyscientists, we know todaythat not all cells move

However, the cellularparts are actively moving

Cells are dynamic,

moving, living systems



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INTRODUCTION TO THE CELL



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Human height

Length of somenerve andmuscle cells

10 m

Frog egg

Chicken egg

Unaid

edeye

1 m

100 mm(10 cm)

10 mm(1 cm)

1 mm

Lightmicroscope

Electronmicroscope

100 nm

100 m

10 m

1 m

Most plantand animalcells

Viruses

Nucleus

Most bacteria

Mitochondrion

10 nm

Lipids

Ribosome

Proteins

Mycoplasmas(smallest bacteria)

1 nmSmall molecules

0.1 nm Atoms


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Most cells are microscopic

Most cells cannot be seen without a microscope

Bacteria are the smallest of all cells and requiremagnifications up to 1,000X

Plant and animal cells are 10 times larger than mostbacteria



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Prokaryote vs. Eukaryote

PROKARYOTE plasma membrane PRESENT

Chromosome one or more

Membrane boundorganelles/nucleus

ABSENT/NUCLEOID

SIMPLE

Bacteria and archaea

EUKARYOTE PRESENT

MORE

PRESENT

COMPLEX

All other forms of life


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Nucleoid

Ribosomes

Plasma membrane

Cell wall

Capsule

Flagella

Bacterialchromosome

A typical rod-shapedbacterium

Pili

A thin section through thebacterium Bacillus coagulans

(TEM)

Fig 4.3 A structural diagram (left) and electron micrograph (right) of a typicalprokaryotic cell.


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Eukaryotic cells are partitioned intofunctional compartments

There are four life processes in eukaryotic cellsthat depend upon structures and organelles

1. Manufacturing

2. Breakdown of molecules

3. Energy processing

4. Structural support, movement, and communication



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I. Manufacturing: nucleus, ribosomes, endoplasmicreticulum, and Golgi apparatus

Manufacture of a protein, perhaps an enzyme, involvesall of these


II. Breakdown of molecules: lysosomes, vacuoles,and peroxisomes

Breakdown of an internalized bacterium by a phagocyticcell would involve all of these


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III. Energy processing: mitochondria in animalcells and chloroplasts in plant cells

Generation of energy-containing molecules, such asadenosine triphosphate, occurs in mitochondria and

chloroplasts


IV. Structural support, movement, andcommunication: cytoskeleton, plasma membrane,and cell wall

Example:movement of phagocytic cells to an infectedarea


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10. Smooth endoplasmicreticulum

11. Roughendoplasmicreticulum

CYTOSKELETON:

1. NUCLEUS:

2. Nuclear envelope

3. Chromosomes

4. Nucleolus

5. Ribosomes

6. Golgiapparatus

7. Plasma membrane

9. Mitochondrion

Peroxisome

13. Centriole

12. Lysosome

Microtubule

Intermediatefilament

Microfilament


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Smoothendoplasmicreticulum

Rough endoplasmicreticulum

CYTOSKELETON:

NUCLEUS:

Nuclear envelope

Chromosome

NucleolusRibosomes

Golgiapparatus

Plasma membrane

Mitochondrion

Peroxisome

Cell wall

Central vacuole

Microtubule

Intermediatefilament

Microfilament

Cell wall of

adjacent cell

Chloroplast

Plasmodesmata


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PARTNERSHIP/GROUPING

1. Endoplasmic Reticulum(Smooth and Rough)

2. Ribosome

3. Mitochondria

4. Vacuole

5. Centrioles

6. Golgi Apparatus

7. Cell wall

8. Plasma Membrane

9. Flagella10. Lysosomes

11. Nucleus

12. Cilia

13. Chloroplast

14. Cytoplasm


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Animal vs. Plant Cell

ORGANELLE ANIMAL PLANT

EndoplasmicReticulum

(Smooth andRough)

RibosomeMitochondria

Vacuole

Centrioles

Golgi ApparatusCell wall

Plasma Membrane

Present PresentPresent PresentPresent Present

One or more smallvacuoles (much

smaller than plantcells).

One, large centralvacuole taking up 90%

of cell volume

Present in allanimal cells

Only present inlower plant forms.

Present PresentAbsent Presentonly cell

membranecell wall and a cell

membrane


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Animal vs. Plant Cell

ORGANELLE ANIMAL PLANT

Flagella

LysosomesNucleus

Cilia

ChloroplastCytoplasm

May be found insome cells May be found insome cells

Lysosomes occurin cytoplasm. Lysosomes usuallynot evident.

Present PresentPresent It is very rare

Animal cellsdon't have

chloroplasts

Plant cells havechloroplasts

because they maketheir own foodPresent Present


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The nucleus is the cells genetic control center

The nucleuscontrols the cells activities and is

responsible for inheritance Inside is a complex of proteins and DNA called

chromatin, which makes up the cells chromosomes

DNA is copied within the nucleus prior to cell division



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4.6 The nucleus is the cells genetic control center

The nuclear envelope is a double membranewith pores that allow material to flow in and out ofthe nucleus

It is attached to a network of cellular membranes calledthe endoplasmic reticulum



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Two membranes ofnuclear envelope Nucleus

Nucleolus

Chromatin

Pore

EndoplasmicreticulumRibosomes


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4.7 Ribosomes make proteins for use in the celland export

Ribosomesare involved in the cells proteinsynthesis

Ribosomes are synthesized in the nucleolus, which isfound in the nucleus

Cells that must synthesize large amounts of proteinhave a large number of ribosomes



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4.7 Ribosomes make proteins for use in the celland export

Some ribosomes are free ribosomes; others arebound

Free ribosomes are suspended in the cytoplasm

Bound ribosomes are attached to the endoplasmicreticulum (ER) associated with the nuclear envelope



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Cytoplasm

Endoplasmic reticulum (ER)

Free ribosomes

Bound ribosomes

Ribosomes

ER

SmallsubunitDiagram ofa ribosome

TEM showing ERand ribosomes

Largesubunit


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4.8 Overview: Many cell organelles are connectedthrough the endomembrane system

The membranes within a eukaryotic cell arephysically connected and compose the

endomembrane system The endomembrane system includes the nuclear

envelope, endoplasmic reticulum (ER), Golgi apparatus,lysosomes, vacuoles, and the plasma membrane



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4.8 Overview: Many cell organelles are connectedthrough the endomembrane system

Some components of the endomembrane systemare able to communicate with others with

formation and transfer of small membranesegments called vesicles

One important result of communication is the synthesis,storage, and export of molecules



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4.9 The endoplasmic reticulum is a biosyntheticfactory

There are two kinds of endoplasmic reticulumsmooth and rough

Smooth ER lacks attached ribosomes

Rough ER lines the outer surface of membranes

They differ in structure and function

However, they are connected



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Smooth ER

Nuclearenvelope

Ribosomes

Rough ER


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Smooth ER is involved in a variety of diversemetabolic processes

For example, enzymes produced by the smooth ER areinvolved in the synthesis of lipids, oils, phospholipids,and steroids



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Rough ER makes additional membrane for itself

and proteins destined for secretion

Once proteins are synthesized, they are transported invesicles to other parts of the endomembrane system



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Transport vesiclebuds off

Secretoryproteininside trans-port vesicle

Glycoprotein

Polypeptide

Ribosome

Sugarchain

Rough ER

1

2

3

4


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4.10 The Golgi apparatus finishes, sorts, andships cell products

The Golgi apparatus functions in conjunction withthe ER by modifying products of the ER

Products travel in transport vesicles from the ER to the

Golgi apparatus

One side of the Golgi apparatus functions as a receivingdock for the product and the other as a shipping dock

Products are modified as they go from one side of the Golgiapparatus to the other and travel in vesicles to other sites



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Golgi apparatusGolgiapparatus

Receiving side ofGolgi apparatus

Transport

vesiclefrom ER

New vesicleforming

Shipping sideof Golgi apparatus

Transportvesicle fromthe Golgi

4 11 L di i


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4.11 Lysosomes are digestive compartmentswithin a cell

A lysosome is a membranous sac containingdigestive enzymes

The enzymes and membrane are produced by the ERand transferred to the Golgi apparatus for processing

The membrane serves to safely isolate these potent

enzymes from the rest of the cell


4 11 L di ti t t


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4.11 Lysosomes are digestive compartmentswithin a cell

One of the several functions of lysosomes is toremove or recycle damaged parts of a cell

The damaged organelle is first enclosed in a membranevesicle

Then a lysosome fuses with the vesicle, dismantling itscontents and breaking down the damaged organelle


Animation: Lysosome Formation
http://04_11lysosomeformation_a.html/


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Digestiveenzymes

Lysosome

Plasmamembrane


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Digestiveenzymes

Lysosome

Plasmamembrane

Food vacuole


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Digestiveenzymes

Lysosome

Plasmamembrane

Food vacuole


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Digestiveenzymes

Lysosome

Plasmamembrane

Food vacuole

Digestion


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Lysosome

Vesicle containing

damaged mitochondrion


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Lysosome

Vesicle containing



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Lysosome

Vesicle containing


Digestion

4 12 Vacuoles function in the general


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4.12 Vacuoles function in the generalmaintenance of the cell

Vacuoles are membranous sacs that are found ina variety of cells and possess an assortment offunctions

Examples are the central vacuole in plants withhydrolytic functions, pigment vacuoles in plants toprovide color to flowers, and contractile vacuoles insome protists to expel water from the cell


Video: ParameciumVacuole
http://04_12bparameciumvacuole_sv.mpg/


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Nucleus

Chloroplast

Centralvacuole


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Nucleus

Contractilevacuoles

Figure 4.12B Contractile vacuoles in Paramecium, a single-celled organism.

4 13 A review of the structures involved in


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4.13 A review of the structures involved inmanufacturing and breakdown

The following figure summarizes the relationshipsamong the major organelles of the endomembranesystem


N l


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Nucleus

VacuoleLysosome Plasma

membrane

SmoothER

Nuclearmembrane

Golgi

apparatus

Rough ER

Transportvesicle

Transportvesicle


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ENERGY-CONVERTINGORGANELLES


4 14 Mitochondria harvest chemical energy from


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4.14 Mitochondria harvest chemical energy fromfood

Cellular respiration is accomplished in themitochondria of eukaryotic cells

Cellular respiration involves conversion of chemicalenergy in foods to chemical energy in ATP (adenosine

triphosphate)

Mitochondria have two internal compartments

The intermembrane space, which encloses the

mitochondrial matrix where materials necessary for ATPgeneration are found


Mitochondrion


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Mitochondrion

Intermembrane

space

Innermembrane

Cristae

Matrix

Outermembrane

4 15 Chloroplasts convert solar energy to


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4.15 Chloroplasts convert solar energy tochemical energy

Chloroplasts are the photosynthesizingorganelles of plants

Photosynthesis is the conversion of light energy tochemical energy of sugar molecules

Chloroplasts are partitioned into compartments

The important parts of chloroplasts are the stroma,thylakoids, and grana



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Chloroplast

Stroma

Inner and outermembranes

Granum

Intermembranespace

4 16 EVOLUTION CONNECTION:


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4.16 EVOLUTION CONNECTION:Mitochondria and chloroplasts evolved byendosymbiosis

When compared, you find that mitochondria andchloroplasts have (1) DNA and (2) ribosomes

The structure of both DNA and ribosomes is very similar

to that found in prokaryotic cells, and mitochondria andchloroplasts replicate much like prokaryotes

The hypothesis ofendosymbiosis proposes that

mitochondria and chloroplasts were formerly smallprokaryotes that began living within larger cells

Symbiosis benefited both cell types



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Engulfing of

photosyntheticprokaryote

Chloroplast

Mitochondrion

Somecells

Host cell

Mitochondrion

Host cellEngulfingof aerobicprokaryote


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INTERNAL AND EXTERNALSUPPORT: THE CYTOSKELETON

AND CELL SURFACES


4 17 The cells internal skeleton helps organize


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4.17 The cell s internal skeleton helps organizeits structure and activities

Cells contain a network of protein fibers, called thecytoskeleton, that functions in cell structuralsupport and motility

Scientists believe that motility and cellular regulation

result when the cytoskeleton interacts with proteinscalled motor proteins


Video: Cytoplasmic Streaming
http://04_17cytoplasmicstream_sv.mpg/


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VesicleATP

Receptor formotor protein

Microtubuleof cytoskeletonMotor protein(ATP powered)

(a)Microtubule

Vesicles

(b)

0.25 m

4.17 The cells internal skeleton helps organize


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4.17 The cell s internal skeleton helps organizeits structure and activities

The cytoskeleton is composed of three kinds offibers

Microfilaments(actin filaments) support the cellsshape and are involved in motility

Intermediate filaments reinforce cell shape andanchor organelles

Microtubules (made of tubulin) shape the cell and act

as tracks for motor protein



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Microfilament

Actin subunit

7 nm

Intermediate filament

Fibrous subunits

10 nm

Microtubule

Tubulin subunit

25 nm

Nucleus

Nucleus

4.18 Cilia and flagella move when microtubules


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4.18 Cilia and flagella move when microtubulesbend

While some protists have flagella and cilia that areimportant in locomotion, some cells of multicellularorganisms have them for different reasons

Cells that sweep mucus out of our lungs have cilia

Animal sperm are flagellated


Video: ParameciumCilia

Video: Chlamydomonas
http://04_18bchlamydomonas_sv.mpg/http://04_18aparameciumcilia_sv.mpg/


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Cilia

Figure 4.18A Cilia on cells lining the respiratory tract.


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Flagellum

Figure 4.18B Undulating flagellum on a sperm cell.



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A flagellum propels a cell by an undulating,whiplike motion

Cilia, however, work more like the oars of a crewboat

Although differences exist, flagella and cilia have acommon structure and mechanism of movement




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Both flagella and cilia are made of microtubuleswrapped in an extension of the plasma membrane

A ring of nine microtubule doublets surrounds acentral pair of microtubules

This arrangement is called the 9 + 2 pattern and isanchored in a basal body with nine microtubule tripletsarranged in a ring


Animation: Cilia and Flagella

Cross sections:
http://04_18cciliaflagella_a.html/


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Centralmicrotubules

Outer microtubuledoublet

Radial spoke

Dynein arms

Plasmamembrane

Triplet

Flagellum

Basal body

Basal body



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gbend

Cilia and flagella move by bending motor proteinscalled dynein arms

These attach to and exert a sliding force on an adjacentdoublet

The arms then release and reattach a little further alongand repeat this time after time

This walking causes the microtubules to bend


4.19 CONNECTION: Problems with sperm


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pmotility may be environmental or genetic

There has been a decline in sperm quality

A group of chemicals called phthalates used in a varietyof things people use every day may be the cause

On the other hand, there are genetic reasons thatsperm lack motility

Primary ciliary dyskinesia (PCD) is an example



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Figure 4.19 Cross section of immotile sperm flagellum.

4.20 The extracellular matrix of animal cells


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functions in support, movement, andregulation

Cells synthesize and secrete the extracellularmatrix (ECM) that is essential to cell function

The ECM is composed of strong fibers of collagen,

which holds cells together and protects the plasmamembrane

ECM attaches through connecting proteins that bind tomembrane proteins called integrins

Integrins span the plasma membrane and connect tomicrofilaments of the cytoskeleton


Glycoprotein


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EXTRACELLULAR FLUID

Microfilaments

Collagen fiber

Connectingglycoprotein

Integrin

Plasmamembrane

Glycoproteincomplex with longpolysaccharide

CYTOPLASM

4.21 Three types of cell junctions are found in


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yp janimal tissues

Adjacent cells communicate, interact, and adherethrough specialized junctions between them

Tight junctions prevent leakage of extracellular fluidacross a layer of epithelial cells

Anchoring junctions fasten cells together into sheets

Gap junctions are channels that allow molecules toflow between cells


Animation: Desmosomes

Animation: Gap Junctions

Animation: Tight Junctions
http://04_21tightjunctions_a.html/http://04_21gapjunctions_a.html/http://04_21desmosomes_a.html/


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Tight junctions

Anchoring junction

Gap junctions

Plasma membranesof adjacent cells

Extracellular matrix

4.22 Cell walls enclose and support plant cells


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pp p

Plant, but not animal cells, have a rigid cell wall

It protects and provides skeletal support that helpskeep the plant upright against gravity

Plant cell walls are composed primarily of cellulose

Plant cells have cell junctions calledplasmodesmata that serve in communicationbetween cells



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04 Lecture Presentation Cells

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