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Chapter Chapter 44A Tour of the Cell
Copyright © 2009 Pearson Education, Inc.
PowerPoint Lectures for
Biology: Concepts & Connections, Sixth Edition
Campbell, Reece, Taylor, Simon, and Dickey
Lecture by Richard L. MyersTranslated by Nabih Baeshen
Introduction: Cells on the Move
� Cells, the simplest collection of matter that can live, were first observed by Robert Hooke in 1665
� Antoni van Leeuwenhoek later described � Antoni van Leeuwenhoek later described cells that could move– He viewed bacteria with his own hand-
crafted microscopes
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Introduction: Cells on the Move
� The early microscopes provided data to establish the cell theory– That is, all living things are
composed of cells and that all
Paramecium
composed of cells and that all cells come from other cells
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4.1 Microscopes reveal the world of the cell
� A variety of microscopes have been developed for a clearer view of cells and cellular structure
� The most frequently used microscope is the light light light light microscopemicroscopemicroscopemicroscope (LMLMLMLM)—like the one used in biology laboratorieslaboratories– Light passes through a specimen then through
glass lenses into the viewer’s eye– Specimens can be magnified up to 1,000 times
the actual size of the specimen
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4.1 Microscopes reveal the world of the cell
� Microscopes have limitations
– Both the human eye and the microscope Both the human eye and the microscope Both the human eye and the microscope Both the human eye and the microscope have limits of resolution—the ability to distinguish between small structures distinguish between small structures – Therefore, the light microscope cannot provide the details of a small cell’s structure
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Enlarges imageformed by objective
Lens
Magnifies specimen,forming primary
Image
Eyepiece
OcularLens
Specimen
Objective lens
Light microscope (LM)
Focuses lightthrough specimen
Specimen
CondenserLens
Light source
Electron Microscope
Light Microscope
Light Microscope
Light micrograph of a protist, Paramecium.
4.1 Microscopes reveal the world of the cell
� Biologists often use a very powerful microscope called the electron microscopeelectron microscopeelectron microscopeelectron microscope(EMEMEMEM) to view the ultrastructureultrastructureultrastructureultrastructure of cells – It can resolve biological structures as
small as 2 nanometers and can magnify small as 2 nanometers and can magnify up to 100,000 times
– Instead of light, the EM uses a beam of electrons
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Scanning electron micrograph of Paramecium.
C:\WINDOWS\hinhem.scrC:\WINDOWS\hinhem.scr
The sizes of cells and related
objects
Human height
Length of somenerve andmuscle cells
10 m
Frog egg
Chicken egg
Una
ided
eye
1 m
100 mm(10 cm)
10 mm(1 cm)
1 mm
Ligh
t mic
rosc
ope
100 µmMost plant and animal cells
م
Ligh
t mic
rosc
ope
Ele
ctro
n m
icro
scop
e
100 nm
10 µm
1 µm
cells
Viruses
NucleusMost bacteriaMitochondrion
10 nm
Lipids
Ribosome
Proteins
Mycoplasmas(smallest bacteria)
1 nmSmall molecules
0.1 nm Atoms
4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
� Bacteria and archaea are prokaryoticprokaryoticprokaryoticprokaryotic cells� All other forms of life are eukaryoticeukaryoticeukaryoticeukaryotic cells
– Both prokaryotic and eukaryotic cells have a plasma membrane and one or have a plasma membrane and one or more chromosomes and ribosomes
– Eukaryotic cells have a membrane-bound nucleus and a number of other organelles, whereas prokaryotes have a nucleoid and no true organelles
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Nucleoid
Ribosomes
Plasma membrane
Cell wallBacterial
Chromosome
Pili
Cell wall
Capsule
Flagella
Chromosome
A typical rod-shapedBacterium
A thin section through thebacterium Bacillus coagulans
(TEM)
A structural diagram (left) and electron micrograph (right) of a typical prokaryotic cell
4.4 Eukaryotic cells are partitioned into functional compartments
� There are four life processes in eukaryotic cells that depend upon structures and organelles – Manufacturing– Breakdown of molecules– Breakdown of molecules– Energy processing– Structural support, movement, and communication
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Smooth endoplasmicReticulum
RoughEndoplasmic Reticulum
CYTOSKELETON
NUCLEUSNuclear envelope
Chromosomes
Nucleolus Ribosomes
Golgi Apparatus
Central vacuole
MicrotubuleChloroplast
Nuclear pore
Nuclear sap
Plasma membrane
Mitochondrion
Peroxisome
Cell wallIntermediate
filament
Microfilament
Cell wall of adjacent cell
Plasmodesmata
A plant cell
Smooth endoplasmicReticulum
Roughendoplasmic
Reticulum
NUCLEUS
Nuclear envelope
Chromosomes
Nucleolus
Lysosome
Nuclear pore
Nuclear sap
An animal cell
CYTOSKELETON
Ribosomes
GolgiApparatus
Plasma membrane
Mitochondrion
Peroxisome
Centriole
Microtubule
Intermediatefilament
Microfilament
4.4 Eukaryotic cells are partitioned into functional compartments
� Although there are many similarities between animal and plant cells, differences exist – Lysosomes and centrioles are not found in plant cellsin plant cells– Plant cells have a rigid cell wall, chloroplasts, and a central vacuole not found in animal cells
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4.5 The structure of membranes correlates with their functions
� The plasma membrane controls the The plasma membrane controls the The plasma membrane controls the The plasma membrane controls the movement of molecules into and out of the movement of molecules into and out of the movement of molecules into and out of the movement of molecules into and out of the cell, a trait called cell, a trait called cell, a trait called cell, a trait called selective permeabilityselective permeabilityselective permeabilityselective permeability – The structure of the membrane with its – The structure of the membrane with its
component molecules is responsible for this characteristic
– Membranes are made of lipids, proteins, and some carbohydrate, but the most abundant lipids are phospholipids
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Hydrophilic head
Phosphategroup
Hydrophobic tails
Symbol
A Phospholipid molecule
Hydrophilic Heads
Hydrophobic Tails
Hydrophobic region ofProtein
Outside cell
TailsProteinsInside cell
Hydrophilic region ofProtein
Phospholipid bilayer with associated proteins.
4.5 The structure of membranes correlates with their functions
� Phospholipids form a twoPhospholipids form a twoPhospholipids form a twoPhospholipids form a two----layer sheet called layer sheet called layer sheet called layer sheet called a phospholipid bilayera phospholipid bilayera phospholipid bilayera phospholipid bilayer – Hydrophilic heads face outward, and hydrophobic tails Hydrophilic heads face outward, and hydrophobic tails Hydrophilic heads face outward, and hydrophobic tails Hydrophilic heads face outward, and hydrophobic tails
point inwardpoint inwardpoint inwardpoint inward– Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while
hydrophobic tails are shielded from waterhydrophobic tails are shielded from waterhydrophobic tails are shielded from waterhydrophobic tails are shielded from water– Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while Thus, hydrophilic heads are exposed to water, while
hydrophobic tails are shielded from waterhydrophobic tails are shielded from waterhydrophobic tails are shielded from waterhydrophobic tails are shielded from water� Proteins are attached to the surface, and Proteins are attached to the surface, and Proteins are attached to the surface, and Proteins are attached to the surface, and some are embedded into the phospholipid some are embedded into the phospholipid some are embedded into the phospholipid some are embedded into the phospholipid bilayerbilayerbilayerbilayer
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CELL STRUCTURES INVOLVED IN MANUFACTURING AND BREAKDOWNAND BREAKDOWN
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Two membranes ofnuclear envelope
Nucleusا
Nucleolus
Chromatin
PorePore
EndoplasmicReticulum
Ribosomesا
TEM (left) and diagram (right) of the nucleus
Nuclear sap
Cytoplasm
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
RibosomesER
Large subunit
Small subunit
Diagram of a ribosome
TEM showing ERand ribosomes
Large subunit
Ribosomes
Smooth ER
NuclearEnvelope
RibosomesSmooth ER
Rough ER
Smooth and rough endoplasmic reticulum
4.6 The nucleus is the cell’s genetic control center
� The nucleusnucleusnucleusnucleus controls the cell’s activities and is responsible for inheritance– Inside is a complex of proteins and DNA called chromatinchromatinchromatinchromatin, which makes up the cell’s chromosomescell’s chromosomes– DNA is copied within the nucleus prior to cell division
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4.6 The nucleus is the cell’s genetic control center
� The nuclear envelopenuclear envelopenuclear envelopenuclear envelope is a double membrane with pores that allow material to flow in and out of the nucleus – It is attached to a network of cellular – It is attached to a network of cellular
membranes called the endoplasmic reticulum
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4.7 Ribosomes make proteins for use in the cell and export
� RibosomesRibosomesRibosomesRibosomes are involved in the cell’s protein synthesis – Ribosomes are synthesized in the
nucleolus, which is found in the nucleolus, which is found in the nucleus
– Cells that must synthesize large amounts of protein have a large number of ribosomes
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4.7 Ribosomes make proteins for use in the cell and export
� Some ribosomes are free ribosomes; others are bound – Free ribosomes are suspended in
the cytoplasmthe cytoplasm– Bound ribosomes are attached to
the endoplasmic reticulum (ER) associated with the nuclear envelope
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4.8 Overview: Many cell organelles are connected through the endomembrane system
� The membranes within an eukaryotic cell are physically connected and compose the endomembrane systemendomembrane systemendomembrane systemendomembrane system – The endomembrane system includes – 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 connected through the endomembrane system
ية
� Some components of the endomembrane system are able to communicate with others with formation and transfer of small membrane and transfer of small membrane segments called vesiclesvesiclesvesiclesvesicles – One important result of
communication is the synthesis, storage, and export of molecules
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4.9 The endoplasmic reticulum is a biosynthetic factory
� There are two kinds of endoplasmic reticulum—smooth and rough � Smooth ER lacks attached ribosomes� Rough ER lines the outer surface of � Rough ER lines the outer surface of membranes
– They differ in structure and function– However, they are connected
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4.9 The endoplasmic reticulum is a biosynthetic factory
� Smooth ER is involved in a variety Smooth ER is involved in a variety Smooth ER is involved in a variety Smooth ER is involved in a variety of diverse metabolic processes of diverse metabolic processes of diverse metabolic processes of diverse metabolic processes –For example, enzymes of the
smooth ER are involved in the smooth ER are involved in the synthesis of lipids, oils, phospholipids, and steroids
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4.9 The endoplasmic reticulum is a biosynthetic factory
�Rough ER makes additional membrane for itself and proteins destined for secretion –Once proteins are synthesized, –Once proteins are synthesized, they are transported in vesicles to other parts of the endomembrane system
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Transport vesiclebuds off
Secretoryprotein
inside trans-port vesicle
Ribosome
3
4
Synthesis and packaging of a secretory protein by the rough ER
Glycoprotein
Polypeptide
Sugar chain
Rough ER
1
2
3
Golgi apparatus
Golgi apparatus“Receiving” side of
Golgi apparatusجولجي
Transportvesicle
from ER
New vesicleForming
“Shipping” sideof Golgi apparatus
Transport vesicle From the Golgi
The Golgi apparatus
4.10 The Golgi apparatus finishes, sorts, and ships cell products
� The Golgi apparatus functions in conjunction with the 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 receiving dock for the product and the other as a shipping dock– Products are modified as they go from one side of the Golgi apparatus to the other and travel in vesicles to other sites
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4.11 Lysosomes are digestive compartments within a cell
� A lysosome is a membranous sac containing digestive enzymes – The enzymes and membrane are
produced by the ER and transferred to the Golgi apparatus for processingproduced by the ER and transferred to the Golgi apparatus for processing
– The membrane serves to safely isolate these potent enzymes from the rest of the cell
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4.11 Lysosomes are digestive compartments within a cell
� One of the several functions of lysosomes is to remove or recycle damaged parts of a cell – The damaged organelle is first enclosed
in a membrane vesiclein a membrane vesicle– Then a lysosome fuses with the vesicle,
dismantling its contents and breaking down the damaged organelle
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Animation: Lysosome Formation
DigestiveEnzymes
Lysosome
Plasma membrane
Lysosome fusing with a food vacuole and digesting food
DigestiveEnzymes
LysosomePlasma membrane
Food vacuole
Lysosome fusing with a food vacuole and digesting food
DigestiveEnzymes
Lysosome
Plasma membrane
Food vacuole
Lysosome fusing with a food vacuole and digesting food
DigestiveEnzymes
Lysosome
Plasma membrane
Digestion
Food vacuole
Lysosome fusing with a food vacuole and digesting food
Lysosome
Vesicle containingdamaged mitochondrion
Lysosome fusing with vesicle containing damagedorganelle and digesting and recycling its contents
Lysosome
Vesicle containingdamaged mitochondrion
Lysosome fusing with vesicle containing damagedorganelle and digesting and recycling its contents
Lysosome
DigestionVesicle containing
damaged mitochondrion
Digestionا
Lysosome fusing with vesicle containing damagedorganelle and digesting and recycling its contents
4.12 Vacuoles function in the general maintenance of the cell
� VacuolesVacuolesVacuolesVacuoles are membranous sacs that are found in a variety of cells and possess an assortment of functions – Examples are the central vacuole in plants with hydrolytic functions, plants with hydrolytic functions, pigment vacuoles in plants to provide color to flowers, and contractile vacuoles in some protists to expel water from the cell
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Video: Paramecium Vacuole
Nucleus
Chloroplast
CentralVacuoleVacuole
Central vacuole in a plant cell
Nucleus
ContractileVacuoles
Contractile vacuoles in Paramecium, a single-celled organism
4.13 A review of the structures involved in manufacturing and breakdown
(
�The following figure summarizes the relationships among the major organelles of the major organelles of the endomembrane system
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Nucleus
Smooth ER
NuclearMembrane
Rough ER
TransportVesicle
TransportVesicle
VacuoleLysosomePlasma
Membrane
GolgiApparatus
Connections among the organelles of the endomembrane system
ENERGY-CONVERTING ORGANELLESORGANELLES
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Mitochondrion
IntermembraneSpace
OuterMembrane
InnerMembrane
Cristae
MatrixThe mitochondrion
Chloroplast
Stromaحشوة
Inner and outerMembranes
Granum
IntermembraneSpace The chloroplast
4.14 Mitochondria harvest chemical energy from food
� Cellular respiration is accomplished in the mitochondriamitochondriamitochondriamitochondria of eukaryotic cells – Cellular respiration involves conversion of chemical energy in foods to chemical energy in ATP (adenosine triphosphate)energy in ATP (adenosine triphosphate)– Mitochondria have two internal compartments
– The intermembrane spaceintermembrane spaceintermembrane spaceintermembrane space, which encloses the mitochondrial matrixmitochondrial matrixmitochondrial matrixmitochondrial matrixwhere materials necessary for ATP generation are foundCopyright © 2009 Pearson Education, Inc.
4.15 Chloroplasts convert solar energy to chemical energy
� ChloroplastsChloroplastsChloroplastsChloroplasts are the photosynthesizing organelles of plants – PhotosynthesisPhotosynthesisPhotosynthesisPhotosynthesis is the conversion of light energy to chemical energy of sugar moleculessugar molecules
� Chloroplasts are partitioned into compartments– The important parts of chloroplasts are the stroma, thylakoids, and grana
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INTERNAL AND EXTERNAL
SUPPORT: THE CYTOSKELETON SUPPORT: THE CYTOSKELETON
AND CELL SURFACES
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4.17 The cell’s internal skeleton helps organize its structure and activities
� Cells contain a network of protein fibers, called the cytoskeletoncytoskeletoncytoskeletoncytoskeleton, that functions in cell structural support and motility – Scientists believe that motility and
cellular regulation result when the cytoskeleton interacts with proteins called motor proteins
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4.17 The cell’s internal skeleton helps organize its structure and activities
� The cytoskeleton is composed of three kinds of fibers – MicrofilamentsMicrofilamentsMicrofilamentsMicrofilaments (actin filaments) support the cell’s shape and are involved in motility– Intermediate filamentsIntermediate filamentsIntermediate filamentsIntermediate filaments reinforce cell shape and anchor
organelles– Intermediate filamentsIntermediate filamentsIntermediate filamentsIntermediate filaments reinforce cell shape and anchor
organelles– MicrotubulesMicrotubulesMicrotubulesMicrotubules (made of tubulin) shape the cell and act as tracks for motor protein
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VesicleATPح Receptor for
motor protein
Microtubuleof cytoskeleton
Motor protein (ATP powered)
ATPالـ
Microtubuleأ Vesicles 0.25 µm
Diagram
Motor proteins and the cytoskeleton
EM micrograph
Nucleus
Nucleus
Microfilament
Actin subunit
7 nm
Intermediate filament
Fibrous subunits
10 nm
Microtubule
Tubulin subunit
25 nm
Fibers of the cytoskeleton
4.18 Cilia and flagella move when microtubules bend
� While some protists have flagella and cilia that are important in locomotion, some cells of multicellular organisms have them for different reasons– Cells that sweep mucus out of our lungs have cilia– Cells that sweep mucus out of our lungs have cilia– Animal sperm are flagellated
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Cilia أ
Cilia on cells lining the respiratory tract
Flagellum
Undulating flagellum on a sperm cell
4.18 Cilia and flagella move when microtubules bend
� Although differences exist, flagella and cilia have a common structure and mechanism of movement
� Both flagella and cilia are made of � Both flagella and cilia are made of microtubules wrapped in an extension of the plasma membrane
� A ring of nine microtubule doublets surrounds a central pair of microtubules
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CentralMicrotubules
Outer microtubule doublet
Radial spoke
Dynein arms
Plasma
Cross sections:
Flagellum
PlasmaMembrane
Triplet
Basal body
Structure of a eukaryotic flagellum or cilium
4.20 The extracellular matrix of animal cells functions in support, movement, and regulation
� Cells synthesize and secrete the extracellular matrixextracellular matrixextracellular matrixextracellular matrix (ECMECMECMECM) that is essential to cell function– The ECM is composed of strong fibers of collagen,
which holds cells together and protects the plasma membrane
– ECM attaches through connecting proteins that bind to – ECM attaches through connecting proteins that bind to membrane proteins called integrinsintegrinsintegrinsintegrins
– Integrins span the plasma membrane and connect to microfilaments of the cytoskeleton
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EXTRACELLULAR FLUID
Collagen fiber
Connectingglycoprotein
Integrin
Glycoproteincomplex with long
Polysaccharide
Microfilaments
Integrin
PlasmaMembrane
CYTOPLASM
The extracellular matrix (ECM) of an animal cell
4.21 Three types of cell junctions are found in animal tissues
� Adjacent cells communicate, interact, and adhere through specialized junctionsbetween them– Tight junctionsTight junctionsTight junctionsTight junctions prevent leakage of extracellular fluid across a layer of epithelial cellsepithelial cells– Anchoring junctionsAnchoring junctionsAnchoring junctionsAnchoring junctions fasten cells together into sheets– Gap junctionsjunctionsjunctionsjunctions are channels that allow molecules to flow between cells
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Tight junctions
Anchoring junction
Gap junctionsGap junctions
Plasma membranesof adjacent cells
Extracellular matrix
Three types of cell junctions in animal tissues
4.22 Cell walls enclose and support plant cells
� Plant, but not animal cells, have a rigid cell cell cell cell wallwallwallwall– It protects and provides skeletal support that helps keep the plant upright against gravitygravity– Plant cell walls are composed primarily of cellulose
� Plant cells have cell junctions called plasmodesmata plasmodesmata plasmodesmata plasmodesmata that serve in communication between cellsCopyright © 2009 Pearson Education, Inc.
Vacuole
Walls of twoadjacent
plant cells
Plasmodesmata
Cytoplasm
Primary cell wall
Plasma membrane
Secondary cell wall
Plant cell walls and cell junction
FUNCTIONAL CATEGORIES OF CELL STRUCTURESOF CELL STRUCTURES
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4.23 Review: Eukaryotic cell structures can be grouped on the basis of four basic functions
� It is possible to group cell organelles into four categories based on general functions of based on general functions of organelles– In each category structure is correlated with function
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Tissues
ANIMAL TISSUESANIMAL TISSUES
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20.1 Structure fits function at all levels of organization in the animal body
� Anatomy—structure� Physiology—function� Animals consist of a hierarchy of levels of
organization
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20.3 Tissues are groups of cells with a common structure and function
� Animals have four main categories of tissues
– Epithelial tissue
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– Connective tissue– Muscle tissue– Nervous tissue
20.4 Epithelial tissue covers the body and lines its organs and cavities
� Epithelial cellsEpithelial cellsEpithelial cellsEpithelial cells come in three shapes– Squamous—like a fried egg– Squamous—like a fried egg– Cuboidal—as tall as they are wide– Columnar—taller than they are wide
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Apical surface ofepithelium
Cell nucleiUnderlying Tissue
Basallamina
Simple squamous epithelium(air sacs of the lung)
Pseudostratifiedciliated columnar
Epithelium(respiratory tract)
A D
Simple cuboidal epithelium(kidney (ا
Simple columnar epithelium(intestine )
Stratified squamous epithelium(esophagus)
B
CE
Types of epithelial tissue
� Stratified epithelial cells are stacked on top of each other
20.4 Epithelial tissue covers the body and lines its organs and cavities
stacked on top of each other
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Types of epithelial tissue;Stratified squamus epithelium
(lining the esophagus)
E Stratified squamous epithelium(esophagus)
20.5 Connective tissue binds and supports other tissues
�Connective tissueConnective tissueConnective tissueConnective tissue can be grouped into six major types
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Fat droplets
Adipose tissue
Collagen fibers
Cell nucleusCartilage ا
(at the end of a bone)
Matrix
Cartilage-Forming cells
Central
D
C
White bloodCells
Red bloodcell
Blood الدم
Plasma
Loose connective tissue(under the skin)
Elastic fibers
Collagen fiber
CellFibrousconnective tissue(forming a tendon)
Collagen fibers CentralCanal
Matrix
Bone-Forming Cells
Bone ا
B
AF
E
Types of connective tissue
20.6 Muscle tissue functions in movement
�Skeletal muscleSkeletal muscleSkeletal muscleSkeletal muscle causes voluntary movements
�Cardiac muscle Cardiac muscle Cardiac muscle Cardiac muscle pumps blood�Cardiac muscle Cardiac muscle Cardiac muscle Cardiac muscle pumps blood�Smooth muscle Smooth muscle Smooth muscle Smooth muscle moves walls of
internal organs, such as the intestines
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Unit of musclecontraction
Nucleus
Nucleus
Junction betweentwo cells
Nucleus
Muscle fiber
Cardiac muscleB
Muscle fiberMuscle fiber
Cardiac muscle
Smooth muscle
Skeletal muscle
C
B
A
The three types of muscle
20.7 Nervous tissue forms a communication network
� NeuronsNeuronsNeuronsNeurons carry signals by conducting electrical impulsesSupporting cells insulate axons and � Supporting cells insulate axons and nourish neurons
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Cell body
Nucleus
Neurons in thespinal cord
20.8 Organs are made up of tissues
� Each tissue performs specific functions� The heart has epithelial, connective, and
nervous tissues– Epithelia line the heart chambers– Epithelia line the heart chambers– Connective tissues make the heart
elastic– Neurons regulate contractions
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Small intestine
Lumen
Epithelial tissue(columnar epithelium)
Lumen
Tissue layersof the small
intestine wall
Epithelial tissue
Connective tissue
Smooth muscle tissue(2 layers )
Connective tissue
� Artificial skin� Used to heal burn
20.9 CONNECTION: Bioengineers are learning toproduce tissues and organs for transplants
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laboratory-grown bladder
PLANT TISSUES
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31.5 Three tissue systems make up the plant body
� Dermal tissueDermal tissueDermal tissueDermal tissue– Outer protective covering
� Vascular tissueVascular tissueVascular tissueVascular tissue– Support and long-distance transport
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� Ground tissueGround tissueGround tissueGround tissue
– Bulk of the plant body– Food production, storage, support
31.5 Three tissue systems make up the plant body
�Dermal tissueDermal tissueDermal tissueDermal tissue– Layer of tightly packed cells called the epidermisepidermisepidermisepidermis– First line of defense against damage
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– First line of defense against damage and infection– Waxy layer called cuticlecuticlecuticlecuticle on top of epidermis, reduces water loss
31.5 Three tissue systems make up the plant body
� Vascular tissueVascular tissueVascular tissueVascular tissue– Composed of xylem and phloem– Arranged in bundles
� Ground tissueGround tissueGround tissueGround tissue
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� Ground tissueGround tissueGround tissueGround tissue– Lies between dermal and vascular tissue– Eudicot stem ground tissue is divided into pith and cortex– Leaf ground tissue is called mesophyll
Eudicot leafXylem
Phloem
Vein
GuardCells
Stoma
Sheath
Eudicot stemVascular
bundle
Cortex
Mesophyll ا
Cuticle
Upper epidermis
Lower epidermis
Monocot stemVascularBundle
The three plant tissue systems
Pith
Epidermis
Eudicot root
Endodermis
Cortex
Epidermis
Phloem
XylemVascularcylinder
Epidermis
Key
Ground tissue systemDermal tissue system
Vascular tissue system
Eudicot leaf
XylemPhloemVein
Cuticle
Upper epidermis
Key
Ground tissue system
Dermal tissue system
Vascular tissue system
PhloemVein
GuardCells
Stoma
Sheath
Mesophyll ا
Lower epidermis
The three plant tissue systems
Eudicot stem
Vascularbundle
Cortex
Monocot stem
VascularBundle
Key
Ground tissue system
Dermal tissue system
Vascular tissue system
Pith
Epidermis Epidermis
The three plant tissue systems
Cortex
Epidermis
Phloem
XylemVascularcylinder
Eudicot root
Endodermis
CortexKey
Ground tissue system
Dermal tissue system
Vascular tissue system
The three plant tissue systems
31.5 Three tissue systems make up the plant body
� Plants cells have three structures that distinguish them from animals cells
– Chloroplasts used in photosynthesis
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– Chloroplasts used in photosynthesis– A large, fluid-filled vacuole– A cell wall composed of cellulose
31.6 Plant cells and tissues are diverse in structure and function
� Plant cell wall– Some plant cell walls have two layers
– Primary cell wall—outermost layer– Secondary cell wall—tough layer inside primary
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– Secondary cell wall—tough layer inside primary wall
– A sticky layer called the middle lamella lies between adjacent plant cells
– Openings in cell walls called plasmodesmata allow cells to communicate and exchange materials easily
Secondarycell wall Middle lamella
Cell wallsPrimary cell wall
Centralvacuole
ChloroplastNucleus ا
Endoplasmicreticulum
Mitochondrion
Pit
Plasmodesmata
Plasmamembrane
Cell walls ofadjoining cells
Golgiapparatus
Ribosomes
Microtubulesأ
Plasma membrane
The structure of a plant cell
� Plant cell structure is related to function� There are five major types of plant cells
– Parenchyma cellsParenchyma cellsParenchyma cellsParenchyma cells
31.6 Plant cells and tissues are diverse in structure and function
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– Collenchyma cellsCollenchyma cellsCollenchyma cellsCollenchyma cells– Sclerenchyma cellsSclerenchyma cellsSclerenchyma cellsSclerenchyma cells– WaterWaterWaterWater----conducting cellsconducting cellsconducting cellsconducting cells– FoodFoodFoodFood----conducting cellsconducting cellsconducting cellsconducting cells
31.6 Plant cells and tissues are diverse in structure and function
� Parenchyma cells– Most abundant cell type– Thin primary cell wall– Lack secondary cell wall
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– Lack secondary cell wall– Alive at maturity– Function in photosynthesis, food and water storage
Primarycell wall
(thin)
Starch-storing vesicles
Pit
Parenchyma cell
� Collenchyma cells– Unevenly thickened primary cell wall– Lack secondary cell wall
31.6 Plant cells and tissues are diverse in structure and function
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– Lack secondary cell wall– Alive at maturity– Provide flexible support
Primarycell wall(thick)
Collenchyma cell
� Sclerenchyma cells– Thick secondary cell wall containing lignin, (lignin is a
main component of wood)– Dead at maturity– Rigid support
31.6 Plant cells and tissues are diverse in structure and function
Copyright © 2009 Pearson Education, Inc.
– Two types of sclerenchyma cells are fibers and sclereids
– Fibers—long and thin, arranged in bundles– Sclereids—shorter than fibers, present in nut
shells and pear tissue
Primarycell wall
Sclereid
Pits
Secondarycell wall
Sclereid cells
Secondarycell wall
Pits
Primarycell wall
Fiber
Fiber cells
Sclerenchyma cells:fiber (left) and sclereid (right)
Secondarycell wall
Pits
Primarycell wall
Fiber
Fiber cells
Sclerenchyma cells: fiber
Secondarycell wall Sclereid cells
Primarycell wall
Sclereid
Pits
Sclerenchyma cells: sclereid (right)
� Water conducting cells—tracheids and vessel elements
– Both have thick secondary cell walls
31.6 Plant cells and tissues are diverse in structure and function
Copyright © 2009 Pearson Education, Inc.
– Both are dead at maturity– Chains of tracheids and vessel elements
form tubes that make up the vascular tissue called xylemxylemxylemxylem
Pits Tracheids
Vessel element
PitsOpeningsin end wall
Water-conducting cells
� FoodFoodFoodFood----conducting cellsconducting cellsconducting cellsconducting cells————sieve tube memberssieve tube memberssieve tube memberssieve tube members– No secondary cell wall– Alive at maturity but lack most organelles– Companion cells
31.6 Plant cells and tissues are diverse in structure and function
Copyright © 2009 Pearson Education, Inc.
– Contain organelles– Control operations of sieve tube members
– Chains of sieve tube members, separated by porous sieve plates, form the vascular tissue called phloemphloemphloemphloem
Primarycell wall
Companion cell
Sieve plate
Cytoplasm
Food-conducting cell (sieve-tube member)
Meristematic tissues
� These are located at the tips of roots and stems, between the
31.6 Plant cells and tissues are diverse in structure and function
roots and stems, between the water- and food-conducting tissues of stems, and at various other places in plant bodies
Loca
tions
of a
pica
l mer
iste
ms,
whi
ch a
re
resp
onsi
ble
for
prim
ary
grow
th
Axillary buds
Terminal bud
Loca
tions
of a
pica
l mer
iste
ms,
whi
ch a
re
resp
onsi
ble
for
prim
ary
grow
th
Root tips
Black Arrows = direction of growth
� Meristematic cells are small, thin-walled, frequently cubical, densely packed with protoplasm, and capable of producing new cells by cell-division.
31.6 Plant cells and tissues are diverse in structure and function
� permanent tissues do not become changed into other kinds of tissues as do Meristematic tissues. (source of differentiation :they give rise to all other kinds of tissues)
31.6 Plant cells and tissues are diverse in structure and function
Microscopic photographs of the meristematic cells i n the tip of onion roots showing cell division ( Arrows )
Glossary for chapter 4 (cell and tissues)المصطلح تعريف المصطلح
Cells: the simplest collection of matter that can live.
.ھي أبسط تجمع من المادة يمكنه العيش:الخ�يا
Cell theory: all living things are composed of cells and that all cells come from other cells.
أن كل الكائنات الحية تتكون من خ�يا ، وأن :نظرية الخلية.كل الخ�يا تأتي من خ�يا أخرى
Light microscope (LM ): Light passes through a specimen then through glass lenses into the viewer’s eye.
يمر الضوء خ�ل العينة ومن ثم إلى : المجھر الضوئي.العدسات الزجاجية ومنھا إلى عين المشاھد
Resolution: the ability to distinguish القدرة على التمييز بين التراكيب الصغيرة: قوة ا;ظھار.Resolution: the ability to distinguish between small structures.
.القدرة على التمييز بين التراكيب الصغيرة: قوة ا;ظھار
Electron microscope (EM): a very powerful microscope used to see very small structures.
يستخدم لتوضيح التراكيب الدقيقة جداً :المجھر ا�لكتروني
Prokaryotic cells: cells that have no true organelles and no nucleus.
خ�يا H تحتوي على عضيات حقيقية أو : خ�يا أولية النواة.وH تحتوي على نواة حقيقية, معقدة
Eukaryotic cells : cells that have true organelles and true nucleus.
خ�يا تحتوي على عضيات حقيقية و : خ�يا حقيقية النواة.تحتوي أيضاً على نواة حقيقية
Selective permeability:controlling the movement of molecules into and out of the cell
التحكم في حركة الجزيئات من و إلى :النفاذية ا'صطفائية.الخلية
Phospholipid bilayer: a double layer of phosphorated lipids (fats).
ھي طبقة مزدوجة من الليبيدات :الليبيدات الفسفورية.المفسفرة) الدھون(
Nuclear envelope:double membrane with pores that allow material to flow in and out of the nucleus.
عبارة عن غشاء مزدوج يحتوي على :الغ�ف النووي.ثقوب تسمح بمرور المواد من وإلى النواة
Endoplasmic reticulum: to a network of cellular membranes.
.شبكة من اRغشية الخلوية: الشبكة ا�ندوب�زمية
Ribosomes:are involved in the cell’s protein مسئولة عن بناء البروتين في الخلية :الرايبوزومات.
Glossary for chapter 4 (cell and tissues)
المصطلح تعريف المصطلح
Ribosomes:are involved in the cell’s protein synthesis.
مسئولة عن بناء البروتين في الخلية
Vesicles الحويص�تGolgi apparatus: functions in conjunction with the ER by modifying products of the ER.
يعمل باHشتراك مع الشبكة اHندوب�زمية : جھاز جولجي.على تھيئة منتجات الشبكة اHندوب�زمية
Lysosome: a membranous sac containing digestive enzymes.
عبارة عن كيس غشائي يحتوي إنزيمات :الجسم الھاضم.ھاضمة
Vacuoles: membranous sacs that are found in a variety of cells and possess an assortment of functions.
عبارة عن أكياس غشائية وتوجد في انواع مختلفة :الفجوات.من الخ�يا ولھا وظائف متنوعة
Mitochondria : the organelle responsible for cellular respiration.
.العضي المسئول عن التنفس الخلوي :ميتوكوندريا
Chloroplasts: the photosynthesizing organelles of plants.
ھي عضيات البناء الضوئي في : الب�ستيدات الخضراء.النبات
Photosynthesis: the conversion of light energy to chemical energy of sugar molecules.
ھو تحويل الطاقة الضوئية إلى طاقة :البناء الضوئي.كيميائية في جزيئات السكر
Cytoskeleton: a network of protein fibers, that functions in cell structural support and
شبكة من اRلياف البروتينية والذي له : الھيكل الخلوي.وظائف مثل دعم التراكيب الخلوية والحركة الخلوية
Glossary for chapter 4 (cell and tissues)Glossary for chapter 4 (cell and tissues)المصطلح تعريف المصطلح
that functions in cell structural support and motility.
.وظائف مثل دعم التراكيب الخلوية والحركة الخلوية
Microfilaments : (actin filaments) support the cell’s shape and are involved in motility.
وتعمل على تحديد شكل ) خيوط اRكتين ( : لدقيقةالخيوط .الخلية ودعمه ولھا دور في حركة الخلية
Intermediate filaments: reinforce cell shape and anchor organelles.
تعزز وتدعم شكل الخلية كما وتثبت : الخيوط المتوسطة. العضيات
Microtubules: (made of tubulin) shape the cell and act as tracks for motor protein.
تشكل ) مصنوعة من التوبيولين ( ا?نيبيبات الدقيقة . وتعمل كخطوط سير للبروتينات الحركية
Extracellular matrix (ECM ): composed of strong fibers of collagen, which holds cells together and protects the plasma membrane.
من الياف كوHجين قوية تتكون : المواد الخارج خلويةتعمل على تماسك الخ�يا مع بعضھا البعض كما وتقوم
.بحماية الغشاء الب�زمي
Integrins: ECM attaches through connecting proteins that bind to membrane proteins.
تلتصق المواد الخارج خلوية بالخلية عن :ا'نتيجريناتطريق البروتينات الرابطة والتي ترتبط ببروتينات الغشاء
.الخلوي المسماةTight junctions: prevent leakage of extracellular fluid across a layer of epithelial cells.
تمنع تسرب السائل الخلوي الخارجي :ا�تصا'ت المحكمة. عبر طبقة الخ�يا الط�ئية
Anchoring junctions: fasten cells together into sheet.
تشد الخ�يا ببعضھا البعض على ھيئة :ا'تصا'ت المثبتة .صفيحة
Gap junctions: are channels that allow عبارة عن قنوات تسمح بتدفق ومرور :ا'تصا'ت الثغرية
Glossary for chapter 4 (cell and tissues)المصطلح تعريف المصطلح
Gap junctions: are channels that allow molecules to flow between cells.
عبارة عن قنوات تسمح بتدفق ومرور :ا'تصا'ت الثغرية.الجزيئات بين الخ�يا
Cell wall: rigid structures that protect and provide skeletal support that helps keep the plant upright against gravity.
تحمي الجدر الخلوية النبات أغشية صلية :جدر خلوية.وتدعمه ھيكلياً ليبقى منتصباً إلى أعلى ضد الجاذبية
Plasmodesmata:cytoplasmic threads that serve in communication between cells.
خيوط سيتوب�زمية تعمل على اHتصال : الب�زموديزماتا.بين الخ�يا
Smooth muscle:moves walls of internal organs, such as the intestines.
تحرك جدر اRعضاء الداخلية مثل : العضلة الملساء.اRمعاء
Neurons: carry signals by conducting electrical impulses.
تحمل ا;شارات بتوصيل الدفعات :الخ�يا العصبية.الكھربية
Dermal tissue: Outer protective covering. .غطاء خارجي واقي: النسيج الجلديVascular tissue: Support and long-distance الدعم والنقل لمسافات طويلة: النسيج الوعائي.
Glossary for chapter 4 (tissues)المصطلح تعريف المصطلح
Skeletal muscle:causes voluntary movements.
.في الحركة ا;راديةتتسبب :العضلة الھيكلية
Cardiac muscle:pumps blood. .تقوم بضخ الدم: العضلة القلبية
Vascular tissue: Support and long-distance transport.
.الدعم والنقل لمسافات طويلة: النسيج الوعائي
Ground tissue: Bulk of the plant body that functions as food production, storage, support.
و تقوم بوظيفة , تشكل معظم جسم النبات: النسيج ا?ساسي.انتاج الطعام والتخزين والدعم
Epidermis: Layer of tightly packed cells. .طبقة من الخ�يا المرتصة بإحكام: البشرةCuticle: Waxy layer on top of epidermis reduces water loss.
.طبقة شمعية فوق البشرة تقلل من فقدان الماء:ا?دمة
Eudicot stem ساق ذوات الفلقتين
Fibers: long and thin, arranged in bundles. .طويلة ورقيقة وتنتظم في حزم : ?ليافاSclereids:shorter than fibers, present in nut shells and pear tissue.
أقصر من اRلياف وتوجد في قشور :الخ�يا الحجرية.الجوز وأنسجة الكمثرى
Xylem : Chains of tracheids and vessel سل القصيبات والعناصرالوعائية أنابيباً : الخشب�تشكل س
Glossary for chapter 4 (tissues)
المصطلح تعريف المصطلح
Mesophyll : Leaf ground tissue. .النسيج اRساسي في الورقة): النسيج الوسطي(الميزوفيل Middle lamella: A sticky layer lies between adjacent plant cells.
طبقة لزجة تقع بين الخ�يا النباتية :الصفيحة الوسطى.المجاورة
Lignin : the main component of wood. .مكون أساسي للخشب :الليجنين
Xylem : Chains of tracheids and vessel elements form tubes that make up the vascular tissue.
تشكل س�سل القصيبات والعناصرالوعائية أنابيباً : الخشب.مكونة للنسيج الوعائي
Phloem:Chains of sieve tube members, separated by porous sieve plates, form the vascular tissue.
سلسلة من اRنابيب الغربالية يفصل بعضھا عن :اللحاء.بعض صفائح مثقبة غربالية مكونة النسيج الوعائي
Meristematic cells: small, thin-walled, frequently cubical, densely packed with protoplasm, and capable of producing new cells by cell-division.
خ�يا صغيرة ، رقيقة الجدر ، وغالبا :الخ�يا المريستيميةما تكون مكعبة ، و ممتلئة بالبروتوب�زم ، و لھا القدرة
.على إنتاج خ�يا جديدة عن طريق ا;نقسام الخلوى