Chapter 4 cell & tissues (1) [compatibility mode]

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


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


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



� 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


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.


� 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


Scanning electron micrograph of Paramecium.

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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


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


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


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


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


CELL STRUCTURES INVOLVED IN MANUFACTURING AND BREAKDOWNAND BREAKDOWN


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


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


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


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


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


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


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



� 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



�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


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


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


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


Animation: Lysosome Formation

DigestiveEnzymes

Lysosome

Plasma membrane

Lysosome fusing with a food vacuole and digesting food

DigestiveEnzymes

LysosomePlasma membrane

Food vacuole


DigestiveEnzymes

Lysosome

Plasma membrane

Food vacuole


DigestiveEnzymes

Lysosome

Plasma membrane

Digestion

Food vacuole


Lysosome

Vesicle containingdamaged mitochondrion

Lysosome fusing with vesicle containing damagedorganelle and digesting and recycling its contents

Lysosome

Vesicle containingdamaged mitochondrion


Lysosome

DigestionVesicle containing

damaged mitochondrion

Digestionا


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


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


Nucleus

Smooth ER

NuclearMembrane

Rough ER

TransportVesicle

TransportVesicle

VacuoleLysosomePlasma

Membrane

GolgiApparatus

Connections among the organelles of the endomembrane system

ENERGY-CONVERTING ORGANELLESORGANELLES


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


INTERNAL AND EXTERNAL

SUPPORT: THE CYTOSKELETON SUPPORT: THE CYTOSKELETON

AND CELL SURFACES


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

Copyright © 2009 Pearson Education, Inc.Video: Cytoplasmic Streaming

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


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


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


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


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


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


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


Tissues

ANIMAL TISSUESANIMAL TISSUES


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


20.3 Tissues are groups of cells with a common structure and function

� Animals have four main categories of tissues

– Epithelial tissue


– 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


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


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


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


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


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


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


laboratory-grown bladder

PLANT TISSUES


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


� Ground tissueGround tissueGround tissueGround tissue

– Bulk of the plant body– Food production, storage, support


�Dermal tissueDermal tissueDermal tissueDermal tissue– Layer of tightly packed cells called the epidermisepidermisepidermisepidermis– First line of defense against damage


– First line of defense against damage and infection– Waxy layer called cuticlecuticlecuticlecuticle on top of epidermis, reduces water loss


� Vascular tissueVascular tissueVascular tissueVascular tissue– Composed of xylem and phloem– Arranged in bundles

� Ground tissueGround tissueGround tissueGround tissue


� 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


PhloemVein

GuardCells

Stoma

Sheath

Mesophyll ا

Lower epidermis


Eudicot stem

Vascularbundle

Cortex

Monocot stem

VascularBundle

Key




Pith

Epidermis Epidermis


Cortex

Epidermis

Phloem

XylemVascularcylinder

Eudicot root

Endodermis

CortexKey






� Plants cells have three structures that distinguish them from animals cells

– Chloroplasts used in photosynthesis


– 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


– 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



– Collenchyma cellsCollenchyma cellsCollenchyma cellsCollenchyma cells– Sclerenchyma cellsSclerenchyma cellsSclerenchyma cellsSclerenchyma cells– WaterWaterWaterWater----conducting cellsconducting cellsconducting cellsconducting cells– FoodFoodFoodFood----conducting cellsconducting cellsconducting cellsconducting cells


� Parenchyma cells– Most abundant cell type– Thin primary cell wall– Lack secondary cell wall


– 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



– 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



– 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



– 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



– 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


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.


� 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)


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

Science

Chapter 4 cell & tissues (1) [compatibility mode]