Download Cells and Tissues

Cells
and
Tissues
Chapter 4
A Tour of the Cell
PowerPoint Lectures for
Biology: Concepts & Connections, Sixth Edition
Campbell, Reece, Taylor, Simon, and Dickey
Copyright © 2009 Pearson Education, Inc.
Lecture by Richard L. Myers
Translated 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
cells that could move
– He viewed bacteria with his own handcrafted microscopes
Copyright © 2009 Pearson Education, Inc.
Paramecium
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
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
microscope (LM)—like the one used in biology
laboratories
– 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
have limits of resolution—the ability to
distinguish between small structures
– Therefore, the light microscope cannot
provide the details of a small cell’s
structure
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Light microscope (LM)
Enlarges image
formed by objective
Lens
Eyepiece
Ocular
Lens
Magnifies specimen,
forming primary
Image
Objective lens
Specimen
Focuses light
through specimen
Condenser
Lens
Light source
Light
Microscope
Light
Microscope
Electron
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 microscope
(EM) to view the ultrastructure of cells
– It can resolve biological structures as
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.scr
10 m
Human height
1m
100 mm
(10 cm)
Length of some
nerve and
muscle cells
Chicken egg
10 mm
(1 cm)
Unaided eye
Frog egg
100 µm
10 µm
1 µm
100 nm
Most plant
and animal
cells
‫م‬
Nucleus
Most bacteria
Mitochondrion
Mycoplasmas
(smallest bacteria)
Viruses
10 nm
Ribosome
Proteins
Lipids
1 nm
Small molecules
0.1 nm
Atoms
Electron microscope
1 mm
Light microscope
The sizes of cells
and related
objects
4.3 Prokaryotic cells are structurally simpler than eukaryotic
cells
 Bacteria and archaea are prokaryotic cells
 All other forms of life are eukaryotic cells
– Both prokaryotic and eukaryotic cells
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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Pili
Nucleoid
Ribosomes
Plasma membrane
Bacterial
Chromosome
Cell wall
Capsule
A typical rod-shaped
Bacterium
Flagella
A thin section through the
bacterium 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
– Energy processing
– Structural support, movement, and communication
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NUCLEUS
Nuclear envelope
Rough
Endoplasmic Reticulum
Chromosomes
Ribosomes
Nucleolus
Nuclear pore
Smooth endoplasmic
Reticulum
Nuclear sap
Golgi Apparatus
CYTOSKELETON
Central vacuole
Chloroplast
Microtubule
Cell wall
Intermediate
filament
Plasmodesmata
Microfilament
Mitochondrion
Peroxisome
Plasma membrane
Cell wall of adjacent cell
A plant cell
NUCLEUS
An animal cell
Nuclear envelope
Smooth endoplasmic
Reticulum
Chromosomes
Nucleolus
Rough
endoplasmic
Reticulum
Nuclear pore
Nuclear sap
Lysosome
Centriole
Ribosomes
Peroxisome
CYTOSKELETON
Microtubule
Intermediate
filament
Microfilament
Golgi
Apparatus
Plasma membrane
Mitochondrion
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 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
movement of molecules into and out of the
cell, a trait called selective permeability
– 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
Phosphate
group
Symbol
A Phospholipid molecule
Hydrophobic tails
Outside cell
Hydrophobic
region of
Protein
Hydrophilic
Heads
Hydrophobic
Tails
Inside cell
Proteins
Hydrophilic
region of
Protein
Phospholipid bilayer with associated proteins.
4.5 The structure of membranes correlates with their functions
 Phospholipids form a two-layer sheet called
a phospholipid bilayer
– Hydrophilic heads face outward, and hydrophobic tails
point inward
– Thus, hydrophilic heads are exposed to water, while
hydrophobic tails are shielded from water
 Proteins are attached to the surface, and
some are embedded into the phospholipid
bilayer
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CELL STRUCTURES INVOLVED
IN MANUFACTURING
AND BREAKDOWN
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Two membranes of
nuclear envelope
Nucleus
‫ا‬
Nucleolus
Chromatin
Pore
Nuclear sap
Endoplasmic
Reticulum
Ribosomes
‫ا‬
TEM (left) and diagram (right) of the nucleus
Ribosomes
ER
Cytoplasm
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large subunit
TEM showing ER
and ribosomes
Small subunit
Diagram of
a ribosome
Ribosomes
Nuclear
Envelope
Ribosomes
Smooth ER
Rough ER
Smooth and rough endoplasmic reticulum
4.6 The nucleus is the cell’s genetic control center
 The nucleus controls the cell’s activities
and is responsible for inheritance
– Inside is a complex of proteins and DNA
called chromatin, which makes up the
cell’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 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
membranes called the endoplasmic
reticulum
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4.7 Ribosomes make proteins for use in the cell and export
 Ribosomes are involved in the cell’s
protein synthesis
– Ribosomes are synthesized 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 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 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 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
segments 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 biosynthetic factory
 There are two kinds of endoplasmic
reticulum—smooth 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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4.9 The endoplasmic reticulum is a biosynthetic factory
 Smooth ER is involved in a variety
of diverse metabolic processes
– For example, enzymes of 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,
they are transported in vesicles
to other parts of the
endomembrane system
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Transport vesicle
buds off
4
Ribosome
Secretory
protein
inside transport vesicle
3
Sugar chain
1
2
Glycoprotein
Polypeptide
Rough ER
Synthesis and packaging of a secretory protein by the rough ER
“Receiving” side of
Golgi apparatus
‫جولجي‬
Golgi apparatus
Golgi apparatus
Transport
vesicle
from ER
New vesicle
Forming
“Shipping” side
of 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 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 vesicle
– Then a lysosome fuses with the vesicle,
dismantling its contents and breaking
down the damaged organelle
Animation: Lysosome Formation
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Digestive
Enzymes
Lysosome
Plasma membrane
Lysosome fusing with a food vacuole and digesting food
Digestive
Enzymes
Lysosome
Plasma membrane
Food vacuole
Lysosome fusing with a food vacuole and digesting food
Digestive
Enzymes
Lysosome
Plasma membrane
Food vacuole
Lysosome fusing with a food vacuole and digesting food
Digestive
Enzymes
Lysosome
Plasma membrane
Digestion
Food vacuole
Lysosome fusing with a food vacuole and digesting food
Lysosome
Vesicle containing
damaged mitochondrion
Lysosome fusing with vesicle containing damaged
organelle and digesting and recycling its contents
Lysosome
Vesicle containing
damaged mitochondrion
Lysosome fusing with vesicle containing damaged
organelle and digesting and recycling its contents
Lysosome
Vesicle containing
damaged mitochondrion
Digestion
‫ا‬
Lysosome fusing with vesicle containing damaged
organelle and digesting and recycling its contents
4.12 Vacuoles function in the general maintenance of the cell
 Vacuoles 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,
pigment vacuoles in plants to provide
color to flowers, and contractile
vacuoles in some protists to expel
water from the cell
Video: Paramecium Vacuole
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Chloroplast
Nucleus
Central
Vacuole
Central vacuole in a plant cell
Nucleus
Contractile
Vacuoles
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
endomembrane system
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Nuclear
Membrane
Nucleus
Rough ER
Smooth
ER
Transport
Vesicle
Golgi
Apparatus
Lysosome
Transport
Vesicle
Vacuole
Plasma
Membrane
Connections among the organelles of the endomembrane system
ENERGY-CONVERTING
ORGANELLES
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Mitochondrion
Outer
Membrane
Intermembrane
Space
Inner
Membrane
Cristae
The mitochondrion
Matrix
Chloroplast
Stroma
‫حشوة‬
Inner and outer
Membranes
Granum
Intermembrane
Space
The chloroplast
4.14 Mitochondria harvest chemical energy from food
 Cellular respiration is accomplished in the
mitochondria of eukaryotic cells
– Cellular respiration involves conversion of
chemical energy 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 ATP
generation are found
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4.15 Chloroplasts convert solar energy to chemical energy
 Chloroplasts are the photosynthesizing
organelles of plants
– Photosynthesis is the conversion of
light energy to chemical energy of
sugar 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
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 cytoskeleton, 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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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
– Microfilaments (actin filaments) support the
cell’s shape and are involved in motility
– Intermediate filaments reinforce cell shape and anchor
organelles
– Microtubules (made of tubulin) shape the cell
and act as tracks for motor protein
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ATP
Vesicle
‫ح‬
Receptor for
motor protein
Diagram
Motor protein
Microtubule
(ATP powered) of cytoskeleton
ATP ‫الـ‬
Microtubule
‫أ‬
Vesicles
EM micrograph
Motor proteins and the cytoskeleton
0.25 µm
Nucleus
Nucleus
Actin subunit
Fibrous subunits
7 nm
Microfilament
Tubulin subunit
10 nm
25 nm
Intermediate filament
Microtubule
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
– Animal sperm are flagellated
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Cilia‫أ‬
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
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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Cross sections:
Outer microtubule doublet
Central
Microtubules
Radial spoke
Flagellum
Dynein arms
Plasma
Membrane
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 matrix (ECM)
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
membrane proteins called integrins
– Integrins span the plasma membrane and connect
to microfilaments of the cytoskeleton
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Glycoprotein
complex with long
Polysaccharide
EXTRACELLULAR FLUID
Collagen fiber
Connecting
glycoprotein
Integrin
Plasma
Membrane
Microfilaments
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 junctions
between them
– Tight junctions prevent leakage of
extracellular fluid across a layer of
epithelial cells
– Anchoring junctions fasten cells together
into sheets
– Gap junctions are channels that allow
molecules to flow between cells
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Tight junctions
Anchoring junction
Gap junctions
Plasma membranes
of 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
wall
– It protects and provides skeletal support
that helps keep the plant upright against
gravity
– Plant cell walls are composed primarily
of cellulose
 Plant cells have cell junctions called
plasmodesmata that serve in
communication between cells
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Walls of two
adjacent
plant cells
Vacuole
Plasmodesmata
Primary cell wall
Secondary cell wall
Cytoplasm
Plasma membrane
Plant cell walls and cell junction
FUNCTIONAL CATEGORIES
OF 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
organelles
– In each category structure is
correlated with function
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Tissues
ANIMAL 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
– Connective tissue
– Muscle tissue
– Nervous tissue
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20.4 Epithelial tissue covers the body and lines its
organs and cavities
 Epithelial cells come in three shapes
– Squamous—like a fried egg
– Cuboidal—as tall as they are wide
– Columnar—taller than they are wide
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Apical surface of
epithelium
Basal
lamina
Underlying Tissue Cell nuclei
D Pseudostratified
A Simple squamous epithelium
ciliated columnar
Epithelium
(respiratory tract)
(air sacs of the lung)
B Simple cuboidal epithelium
(kidney ‫)ا‬
Types of epithelial tissue
C Simple columnar epithelium
(intestine )
E Stratified squamous epithelium
(esophagus)
20.4 Epithelial tissue covers the body and lines its
organs and cavities
 Stratified epithelial cells are
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 tissue can be
grouped into six major types
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Fat droplets
CartilageForming cells
C Adipose tissue
Cell nucleus
Matrix
Cartilage‫ا‬
(at the end of a bone)
D
Central
Canal
Collagen fibers
Cell
B Fibrous
Matrix
White blood
Cells
connective tissue
(forming a tendon)
BoneForming Cells
Red blood
cell
Collagen fiber
Plasma
Elastic fibers
E
A
Loose connective tissue
(under the skin)
Bone‫ا‬
F Blood ‫الدم‬
Types of connective tissue
20.6 Muscle tissue functions in movement
 Skeletal muscle causes
voluntary movements
 Cardiac muscle pumps blood
 Smooth muscle moves walls of
internal organs, such as the
intestines
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Unit of muscle
contraction
Muscle fiber
Junction between
two cells
Muscle fiber
Nucleus
Muscle fiber
Nucleus
Nucleus
B Cardiac muscle
A Skeletal muscle
C Smooth muscle
The three types of muscle
20.7 Nervous tissue forms a communication network
 Neurons carry signals by conducting
electrical impulses
 Supporting cells insulate axons and
nourish neurons
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Cell body
Nucleus
Neurons in the
spinal 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
– Connective tissues make the heart
elastic
– Neurons regulate contractions
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Tissue layers
of the small
intestine wall
Small intestine
Lumen
Epithelial tissue
(columnar epithelium)
Connective tissue
Smooth muscle tissue
(2 layers )
Connective tissue
Epithelial tissue
Lumen
20.9 CONNECTION: Bioengineers are learning to
produce tissues and organs for transplants
 Artificial skin
 Used to heal burn
laboratory-grown bladder
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PLANT TISSUES
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31.5 Three tissue systems make up the plant body
 Dermal tissue
– Outer protective covering
 Vascular tissue
– Support and long-distance transport
 Ground tissue
– Bulk of the plant body
– Food production, storage, support
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31.5 Three tissue systems make up the plant body
 Dermal tissue
– Layer of tightly packed cells called
the epidermis
– First line of defense against damage
and infection
– Waxy layer called cuticle on top of
epidermis, reduces water loss
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31.5 Three tissue systems make up the plant body
 Vascular tissue
– Composed of xylem and phloem
– Arranged in bundles
 Ground tissue
– Lies between dermal and vascular tissue
– Eudicot stem ground tissue is divided into pith
and cortex
– Leaf ground tissue is called mesophyll
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Cuticle
Eudicot leaf
Xylem
Upper epidermis
Vein
‫ا‬
Mesophyll
Phloem
The three plant
tissue systems
Guard
Cells
Lower epidermis
Stoma
Sheath
Eudicot stem
Vascular
bundle
Vascular
Bundle
Monocot stem
Cortex
Pith
Epidermis
Epidermis
Xylem
Vascular
cylinder
Phloem
Epidermis
Cortex
Endodermis
Eudicot root
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Eudicot leaf
Vein
Cuticle
Xylem
Phloem
Upper epidermis
Mesophyll‫ا‬
Guard
Cells
Lower epidermis
Stoma
Sheath
The three plant tissue systems
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Eudicot stem
Vascular
bundle
Monocot stem
Vascular
Bundle
Cortex
Pith
Epidermis
Epidermis
The three plant tissue systems
Xylem
Phloem
Vascular
cylinder
Epidermis
Cortex
Key
Endodermis
Dermal tissue system
Ground tissue system
Vascular tissue system
Eudicot root
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
– A large, fluid-filled vacuole
– A cell wall composed of cellulose
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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
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
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Nucleus‫ا‬
Chloroplast
Central
vacuole
Cell walls
Endoplasmic
reticulum
Primary cell wall
Secondary
cell wall
Middle lamella
Mitochondrion
Golgi
apparatus
Cell walls of
adjoining cells
Ribosomes
Plasma
membrane
Microtubules
‫أ‬
Plasmodesmata
Plasma membrane
Pit
The structure of a plant cell
31.6 Plant cells and tissues are diverse in structure and
function
 Plant cell structure is related to function
 There are five major types of plant cells
– Parenchyma cells
– Collenchyma cells
– Sclerenchyma cells
– Water-conducting cells
– Food-conducting cells
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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
– Alive at maturity
– Function in photosynthesis, food and water storage
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Primary
cell wall
(thin)
Pit
Starch-storing vesicles
Parenchyma cell
31.6 Plant cells and tissues are diverse in structure and
function
 Collenchyma cells
– Unevenly thickened primary cell wall
– Lack secondary cell wall
– Alive at maturity
– Provide flexible support
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Primary
cell wall
(thick)
Collenchyma cell
31.6 Plant cells and tissues are diverse in structure and function
 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
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Secondary
cell wall
Secondary Sclereid cells
cell wall
Pits
Fiber cells
Primary
cell wall
Fiber
Primary
cell wall
Pits
Sclereid
Sclerenchyma cells:
fiber (left) and sclereid (right)
Pits
Secondary
cell wall
Fiber cells
Primary
cell wall
Fiber
Sclerenchyma cells: fiber
Secondary
cell wall Sclereid cells
Primary
cell wall
Pits
Sclereid
Sclerenchyma cells: sclereid (right)
31.6 Plant cells and tissues are diverse in structure and
function
 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 xylem
Copyright © 2009 Pearson Education, Inc.
Pits
Tracheids
Vessel element
Openings
in end wall
Water-conducting cells
Pits
31.6 Plant cells and tissues are diverse in structure and
function
 Food-conducting cells—sieve 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 phloem
Copyright © 2009 Pearson Education, Inc.
Sieve plate
Companion cell
Primary
cell wall
Cytoplasm
Food-conducting cell (sieve-tube member)
31.6 Plant cells and tissues are diverse in structure and function
Meristematic tissues
 These are located at the tips of
roots and stems, between the
water- and food-conducting tissues
of stems, and at various other
places in plant bodies
Locations of apical meristems, which are
responsible for primary growth
Terminal bud
Axillary buds
Black Arrows = direction of growth
Root tips
31.6 Plant cells and tissues are diverse in structure and function
 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)
31.6 Plant cells and tissues are diverse in structure and function
Microscopic photographs of the meristematic cells in the tip of
onion roots showing cell division (Arrows)
Glossary for chapter 4 (cell and tissues)
‫المصطلح‬
‫تعريف المصطلح‬
.‫هي أبسط تجمع من المادة يمكنه العيش‬: ‫الخاليا‬
Cells: the simplest collection of matter that
can live.
Cell theory: all living things are composed ‫ وأن‬، ‫أن كل الكائنات الحية تتكون من خاليا‬: ‫نظرية الخلية‬
.‫كل الخاليا تأتي من خاليا أخرى‬
of cells and that all cells come from other
cells.
Light microscope (LM): Light passes
‫يمر الضوء خالل العينة ومن ثم إلى‬: ‫المجهر الضوئي‬
. ‫العدسات الزجاجية ومنها إلى عين المشاهد‬
through a specimen then through glass lenses
into the viewer’s eye.
.‫ القدرة على التمييز بين التراكيب الصغيرة‬:‫قوة اإلظهار‬
Resolution: the ability to distinguish
between small structures.
Electron microscope (EM): a very powerful ‫يستخدم لتوضيح التراكيب الدقيقة جدا‬: ‫المجهر اإللكتروني‬
microscope used to see very small structures.
Prokaryotic cells: cells that have no true
‫ خاليا ال تحتوي على عضيات حقيقية أو‬:‫خاليا أولية النواة‬
organelles and no nucleus.
.‫ وال تحتوي على نواة حقيقية‬,‫معقدة‬
Eukaryotic cells :cells that have true
‫ خاليا تحتوي على عضيات حقيقية و‬:‫خاليا حقيقية النواة‬
organelles and true nucleus.
.‫تحتوي أيضا على نواة حقيقية‬
Selective permeability: controlling the
‫ التحكم في حركة الجزيئات من و إلى‬:‫النفاذية االصطفائية‬
.‫الخلية‬
movement of molecules into and out of the
cell
Glossary for chapter 4 (cell and tissues)
‫المصطلح‬
‫تعريف المصطلح‬
Phospholipid bilayer: a double layer of
‫ هي طبقة مزدوجة من الليبيدات‬:‫الليبيدات الفسفورية‬
phosphorated lipids (fats).
.‫(الدهون) المفسفرة‬
Nuclear envelope: double membrane with
‫عبارة عن غشاء مزدوج يحتوي على‬:‫الغالف النووي‬
. ‫ثقوب تسمح بمرور المواد من وإلى النواة‬
pores that allow material to flow in and out
of the nucleus.
.‫ شبكة من األغشية الخلوية‬:‫الشبكة اإلندوبالزمية‬
Endoplasmic reticulum: to a network of
cellular membranes.
.‫ مسئولة عن بناء البروتين في الخلية‬:‫الرايبوزومات‬
Ribosomes: are involved in the cell’s protein
synthesis.
Vesicles
‫الحويصالت‬
Golgi apparatus: functions in conjunction
‫ يعمل باالشتراك مع الشبكة االندوبالزمية‬:‫جهاز جولجي‬
.‫على تهيئة منتجات الشبكة االندوبالزمية‬
with the ER by modifying products of the
ER.
Lysosome: a membranous sac containing
‫عبارة عن كيس غشائي يحتوي إنزيمات‬:‫الجسم الهاضم‬
.‫هاضمة‬
digestive enzymes.
Vacuoles: membranous sacs that are found in ‫عبارة عن أكياس غشائية وتوجد في انواع مختلفة‬:‫الفجوات‬
.‫من الخاليا ولها وظائف متنوعة‬
a variety of cells and possess an assortment
of functions.
Glossary for chapter 4 (cell and tissues)
‫المصطلح‬
‫تعريف المصطلح‬
.‫ العضي المسئول عن التنفس الخلوي‬:‫ميتوكوندريا‬
Mitochondria: the organelle responsible for
cellular respiration.
Chloroplasts: the photosynthesizing
‫ هي عضيات البناء الضوئي في‬:‫البالستيدات الخضراء‬
organelles of plants.
.‫النبات‬
Photosynthesis: the conversion of light
‫ هو تحويل الطاقة الضوئية إلى طاقة‬:‫البناء الضوئي‬
.‫كيميائية في جزيئات السكر‬
energy to chemical energy of sugar
molecules.
Cytoskeleton: a network of protein fibers,
‫ شبكة من األلياف البروتينية والذي له‬:‫الهيكل الخلوي‬
.‫وظائف مثل دعم التراكيب الخلوية والحركة الخلوية‬
that functions in cell structural support and
motility.
Microfilaments :(actin filaments) support
‫ ( خيوط األكتين ) وتعمل على تحديد شكل‬:‫الخيوط لدقيقة‬
the cell’s shape and are involved in motility.
.‫الخلية ودعمه ولها دور في حركة الخلية‬
Intermediate filaments: reinforce cell shape ‫ تعزز وتدعم شكل الخلية كما وتثبت‬:‫الخيوط المتوسطة‬
and anchor organelles.
. ‫العضيات‬
Microtubules: (made of tubulin) shape the
‫األنيبيبات الدقيقة ( مصنوعة من التوبيولين ) تشكل‬
. ‫وتعمل كخطوط سير للبروتينات الحركية‬
cell and act as tracks for motor protein .
Extracellular matrix (ECM): composed of
‫ تتكون من الياف كوالجين قوية‬:‫المواد الخارج خلوية‬
strong fibers of collagen, which holds cells
‫تعمل على تماسك الخاليا مع بعضها البعض كما وتقوم‬
together and protects the plasma membrane.
.‫بحماية الغشاء البالزمي‬
Glossary for chapter 4 (cell and tissues)
‫المصطلح‬
‫تعريف المصطلح‬
‫تلتصق المواد الخارج خلوية بالخلية عن‬: ‫االنتيجرينات‬
‫طريق البروتينات الرابطة والتي ترتبط ببروتينات الغشاء‬
.‫الخلوي المسماة‬
Tight junctions: prevent leakage of
‫ تمنع تسرب السائل الخلوي الخارجي‬:‫اإلتصاالت المحكمة‬
. ‫عبر طبقة الخاليا الطالئية‬
extracellular fluid across a layer of epithelial
cells.
Anchoring junctions: fasten cells together ‫ تشد الخاليا ببعضها البعض على هيئة‬:‫االتصاالت المثبتة‬
into sheet.
. ‫صفيحة‬
Gap junctions: are channels that allow
‫ عبارة عن قنوات تسمح بتدفق ومرور‬:‫االتصاالت الثغرية‬
molecules to flow between cells.
. ‫الجزيئات بين الخاليا‬
Cell wall: rigid structures that protect and
‫ أغشية صلية تحمي الجدر الخلوية النبات‬: ‫جدر خلوية‬
. ‫وتدعمه هيكليا ليبقى منتصبا إلى أعلى ضد الجاذبية‬
provide skeletal support that helps keep the
plant upright against gravity.
Plasmodesmata: cytoplasmic threads that
‫ خيوط سيتوبالزمية تعمل على االتصال‬:‫البالزموديزماتا‬
serve in communication between cells.
.‫بين الخاليا‬
Integrins: ECM attaches through connecting
proteins that bind to membrane proteins.
Glossary for chapter 4 (tissues)
‫المصطلح‬
Skeletal muscle: causes voluntary
movements.
Cardiac muscle: pumps blood.
Smooth muscle: moves walls of internal
organs, such as the intestines.
Neurons: carry signals by conducting
electrical impulses.
Dermal tissue :Outer protective covering.
Vascular tissue: Support and long-distance
transport.
Ground tissue: Bulk of the plant body that
functions as food production, storage,
support.
Epidermis: Layer of tightly packed cells.
Cuticle: Waxy layer on top of epidermis
reduces water loss.
Eudicot stem
‫تعريف المصطلح‬
.‫تتسبب في الحركة اإلرادية‬: ‫العضلة الهيكلية‬
.‫ تقوم بضخ الدم‬:‫العضلة القلبية‬
‫ تحرك جدر األعضاء الداخلية مثل‬:‫العضلة الملساء‬
.‫األمعاء‬
‫ تحمل اإلشارات بتوصيل الدفعات‬:‫الخاليا العصبية‬
.‫الكهربية‬
.‫ غطاء خارجي واقي‬:‫النسيج الجلدي‬
.‫ الدعم والنقل لمسافات طويلة‬:‫النسيج الوعائي‬
‫ و تقوم بوظيفة‬,‫ تشكل معظم جسم النبات‬:‫النسيج األساسي‬
. ‫انتاج الطعام والتخزين والدعم‬
.‫ طبقة من الخاليا المرتصة بإحكام‬:‫البشرة‬
.‫طبقة شمعية فوق البشرة تقلل من فقدان الماء‬:‫األدمة‬
‫ساق ذوات الفلقتين‬
Glossary for chapter 4 (tissues)
‫المصطلح‬
‫تعريف المصطلح‬
.‫ النسيج األساسي في الورقة‬:)‫الميزوفيل (النسيج الوسطي‬
Mesophyll :Leaf ground tissue.
Middle lamella: A sticky layer lies between
‫ طبقة لزجة تقع بين الخاليا النباتية‬:‫الصفيحة الوسطى‬
adjacent plant cells.
.‫المجاورة‬
.‫ مكون أساسي للخشب‬:‫الليجنين‬
Lignin :the main component of wood.
Fibers: long and thin, arranged in bundles.
. ‫ طويلة ورقيقة وتنتظم في حزم‬:‫األلياف‬
Sclereids: shorter than fibers, present in nut
‫ أقصر من األلياف وتوجد في قشور‬:‫الخاليا الحجرية‬
shells and pear tissue.
.‫الجوز وأنسجة الكمثرى‬
Xylem :Chains of tracheids and vessel
‫ تشكل سالسل القصيبات والعناصرالوعائية أنابيبا‬:‫الخشب‬
.‫مكونة للنسيج الوعائي‬
elements form tubes that make up the
vascular tissue.
Phloem: Chains of sieve tube members,
‫سلسلة من األنابيب الغربالية يفصل بعضها عن‬: ‫اللحاء‬
.‫بعض صفائح مثقبة غربالية مكونة النسيج الوعائي‬
separated by porous sieve plates, form the
vascular tissue.
Meristematic cells: small, thin-walled,
‫ وغالبا‬، ‫ رقيقة الجدر‬، ‫خاليا صغيرة‬: ‫الخاليا المريستيمية‬
frequently cubical, densely packed with
‫ و لها القدرة‬، ‫ و ممتلئة بالبروتوبالزم‬، ‫ما تكون مكعبة‬
.‫على إنتاج خاليا جديدة عن طريق اإلنقسام الخلوى‬
protoplasm, and capable of producing new
cells by cell-division.