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PowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE • TAYLOR • SIMON • DICKEY • HOGAN
Chapter 4
Lecture by Edward J. Zalisko
A Tour of the Cell
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Introduction
• Cells have a cytoskeleton that • provides support and • allows some cells to crawl and others to swim.
• Our understanding of nature often goes hand in hand with the invention and refinement of instruments that extend our senses.
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Introduction
• In 1665, Hooke examined a piece of cork under a crude microscope and identified “little rooms” as cells.
• Leeuwenhoek, working at about the same time, used more refined lenses to describe living cells from blood, sperm, and pond water.
• Since the days of Hooke and Leeuwenhoek, improved microscopes have vastly expanded our view of the cell.
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Figure 4.0-1
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Figure 4.0-2
Introduction to the Cell
Chapter 4: Big Ideas
The Nucleus and Ribosomes
The Endomembrane System
Energy-ConvertingOrganelles
The Cytoskeleton andCell Surfaces
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INTRODUCTION TO THE CELL
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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 first microscopes were light microscopes. In a light microscope (LM), visible light passes through a specimen, then through glass lenses, and finally is projected into the viewer’s eye.
• Specimens can be magnified by up to 1,000 times.
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4.1 Microscopes reveal the world of the cell
• Magnification is the increase in an object’s image size compared with its actual size.
• Resolution is a measure of the clarity of an image. In other words, it is the ability of an instrument to show two nearby objects as separate.
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4.1 Microscopes reveal the world of the cell
• Microscopes have limitations. • 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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4.1 Microscopes reveal the world of the cell
• Using light microscopes, scientists studied • microorganisms, • animal and plant cells, and • some structures within cells.
• In the 1800s, these studies led to cell theory, which states that
• all living things are composed of cells and • all cells come from other cells.
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Figure 4.1a
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Figure 4.1b
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Figure 4.1c
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Figure 4.1d
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Figure 4.1e-0
Human heightLength of some nerve and muscle cells
Chicken egg
Frog egg
ParameciumHuman egg
Most plant andanimal cellsNucleusMost bacteriaMitochondrion
Smallest bacteriaViruses
Ribosome
ProteinsLipids
SmallmoleculesAtoms
Una
ided
eye
Ligh
t mic
rosc
ope
Elec
tron
mic
rosc
ope
10 m
1 m
100 mm(10 cm)
10 mm(1 cm)
1 mm
100 nm
10 nm
1 nm
0.1 nm
100 μm
10 μm
1 μm
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Figure 4.1e-1
Human heightLength of some nerve and muscle cells
Chicken egg
Frog egg
ParameciumHuman eggU
naid
ed e
ye
10 m
1 m
100 mm(10 cm)
10 mm(1 cm)
1 mm
100 μm
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Figure 4.1e-2
Frog egg
ParameciumHuman egg
Most plant andanimal cellsNucleusMost bacteriaMitochondrion
Smallest bacteriaViruses
Ribosome
ProteinsLipids
SmallmoleculesAtoms
Ligh
t mic
rosc
ope
Elec
tron
mic
rosc
ope
1 mm
100 nm
10 nm
1 nm
0.1 nm
100 μm
10 μm
1 μm
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4.1 Microscopes reveal the world of the cell
• Beginning in the 1950s, scientists started using a very powerful microscope called the electron microscope (EM) to view the ultrastructure of cells.
• Instead of light, EM uses a beam of electrons. • Electron microscopes can
• resolve biological structures as small as 2 nanometers and
• magnify up to 100,000 times.
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4.1 Microscopes reveal the world of the cell
• Scanning electron microscopes (SEMs) study the detailed architecture of cell surfaces.
• Transmission electron microscopes (TEMs) study the details of internal cell structure.
• Differential interference light microscopes amplify differences in density so that structures in living cells appear almost three-dimensional.
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4.2 The small size of cells relates to the need to exchange materials across the plasma membrane
• Cell size must • be large enough to house DNA, proteins, and
structures needed to survive and reproduce, but • remain small enough to allow for a surface-to-
volume ratio that will allow adequate exchange with the environment.
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Figure 4.2a
Total volume
3
3
1
1
2 6
Total surface areaSurface-to-volume ratio
27 units3 27 units3
54 units2 162 units2
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4.2 The small size of cells relates to the need to exchange materials across the plasma membrane
• The plasma membrane forms a flexible boundary between the living cell and its surroundings.
• Phospholipids form a two-layer sheet called a phospholipid bilayer in which
• hydrophilic heads face outward, exposed to water, and
• hydrophobic tails point inward, shielded from water.
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4.2 The small size of cells relates to the need to exchange materials across the plasma membrane
• Membrane proteins are embedded in the lipid bilayer.
• Some proteins form channels (tunnels) that shield ions and other hydrophilic molecules as they pass through the hydrophobic center of the membrane.
• Other proteins serve as pumps, using energy to actively transport molecules into or out of the cell.
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Figure 4.2b
Outside cell
Inside cell
Hydrophilicheads
Hydrophobictails
Phospholipid
Channelprotein
Hydrophilicregions ofa protein
Hydrophobicregions ofa protein
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Figure 4.UN01
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4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
• Bacteria and archaea are prokaryotic cells. • All other forms of life are composed of eukaryotic
cells. • Eukaryotic cells are distinguished by having
• a membrane-enclosed nucleus and • many membrane-enclosed organelles that perform
specific functions. • Prokaryotic cells are smaller and simpler in
structure.
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4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
• Prokaryotic and eukaryotic cells have • a plasma membrane, • an interior filled with a thick, jellylike fluid called the
cytosol, • one or more chromosomes, which carry genes
made of DNA, and • ribosomes, tiny structures that make proteins
according to instructions from the genes.
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4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
• The inside of both types of cells is called the cytoplasm.
• However, in eukaryotic cells, this term refers only to the region between the nucleus and the plasma membrane.
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4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
• In a prokaryotic cell, • the DNA is coiled into a region called the nucleoid
(nucleus-like) and • no membrane surrounds the DNA.
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4.3 Prokaryotic cells are structurally simpler than eukaryotic cells
• Outside the plasma membrane of most prokaryotes is a fairly rigid, chemically complex cell wall, which
• protects the cell and • helps maintain its shape.
• Some prokaryotes have surface projections. • Short projections help attach prokaryotes to each
other or their substrate. • Longer projections called flagella (singular, flagellum) propel a prokaryotic cell through its liquid environment.
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Figure 4.3-0
Fimbriae
Ribosomes
Nucleoid
Plasma membraneCell wall
CapsuleBacterialchromosome
A typical rod-shapedbacterium
A colorized TEM of the bacterium Escherichia coli
Flagella
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Figure 4.3-1 Fimbriae
Ribosomes
Nucleoid
Plasma membraneCell wall
CapsuleBacterialchromosome
A typical rod-shapedbacterium Flagella
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Figure 4.3-2
A colorized TEM of the bacterium Escherichia coli
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4.4 Eukaryotic cells are partitioned into functional compartments
• A eukaryotic cell contains • a membrane-enclosed nucleus and • various other organelles (“little organs”), which
perform specific functions in the cell.
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4.4 Eukaryotic cells are partitioned into functional compartments
• The structures and organelles of eukaryotic cells perform four basic functions.
1. The nucleus and ribosomes are involved in the genetic control of the cell.
2. The endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes are involved in the manufacture, distribution, and breakdown of molecules.
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4.4 Eukaryotic cells are partitioned into functional compartments
3. Mitochondria in all cells and chloroplasts in plant cells are involved in energy processing.
4. Structural support, movement, and communication between cells are functions of the cytoskeleton, plasma membrane, and cell wall.
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4.4 Eukaryotic cells are partitioned into functional compartments
• The internal membranes of eukaryotic cells partition it into compartments.
• Cellular metabolism, the many chemical activities of cells, occurs within organelles.
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4.4 Eukaryotic cells are partitioned into functional compartments
• Almost all of the organelles and other structures of animals cells are present in plant cells.
• A few exceptions exist. • Lysosomes and centrosomes containing centrioles
are not found in plant cells. • Only the sperm cells of a few plant species have
flagella.
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4.4 Eukaryotic cells are partitioned into functional compartments
• Plant but not animal cells have • a rigid cell wall that contains cellulose, • plasmodesmata, cytoplasmic channels through cell
walls that connect adjacent cells, • chloroplasts, where photosynthesis occurs, and • a central vacuole, a compartment that stores water
and a variety of chemicals.
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Figure 4.4a
Roughendoplasmicreticulum
Smoothendoplasmicreticulum
Golgi apparatus
LysosomeMitochondrion
Centrosome with pair of centrioles
Plasma membrane
Peroxisome
Intermediate filament
MicrofilamentMicrotubule
CYTOSKELETON
NUCLEUSNuclear envelopeNucleolusChromatin
Ribosomes
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Figure 4.4b
Roughendoplasmicreticulum
Smoothendoplasmicreticulum
NUCLEUSNuclear envelopeNucleolusChromatin
Ribosomes
Plasma membrane
Peroxisome
Mitochondrion
MicrofilamentMicrotubule
CYTOSKELETON
Cell wall ofadjacent cell Golgi
apparatus
PlasmodesmaCell wall
Chloroplast
Centralvacuole
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THE NUCLEUS AND RIBOSOMES
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4.5 The nucleus contains the cell’s genetic instructions
• The nucleus • contains most of the cell’s DNA and • controls the cell’s activities by directing protein
synthesis by making messenger RNA (mRNA). • DNA is associated with many proteins and is
organized into structures called chromosomes. • When a cell is not dividing, this complex of proteins
and DNA, called chromatin, appears as a diffuse mass within the nucleus.
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4.5 The nucleus contains the cell’s genetic instructions
• The double membrane nuclear envelope has pores that
• regulate the entry and exit of large molecules and • connect with the cell’s network of membranes called
the endoplasmic reticulum.
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4.5 The nucleus contains the cell’s genetic instructions
• The nucleolus is • a prominent structure in the nucleus and • the site of ribosomal RNA (rRNA) synthesis.
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Figure 4.5
NucleolusNuclearenvelope
Endoplasmic reticulum
Ribosome
Pore Chromatin
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4.6 Ribosomes make proteins for use in the cell and export
• Ribosomes are involved in the cell’s protein synthesis.
• Ribosomes are the cellular components that use instructions from the nucleus, written in mRNA, to build proteins.
• Cells that make a lot of proteins have a large number of ribosomes.
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4.6 Ribosomes make proteins for use in the cell and export
• Some ribosomes are free ribosomes; others are bound.
• Free ribosomes are suspended in the cytosol. • Bound ribosomes are attached to the outside of the
endoplasmic reticulum or nuclear envelope.
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Figure 4.6
Rough ER
Bound ribosomeEndoplasmic reticulum
Protein
Ribosome
Free ribosomemRNA
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THE ENDOMEMBRANE SYSTEM
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4.7 Many organelles are connected in the endomembrane system
• Many of the membranes within a eukaryotic cell are part of the endomembrane system.
• Some of these membranes are physically connected, and others are linked when tiny vesicles (sacs made of membrane) transfer membrane segments between them.
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4.7 Many organelles are connected in the endomembrane system
• Many of these organelles interact in the • synthesis, • distribution, • storage, and • export of molecules.
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4.7 Many organelles are connected in the endomembrane system
• The endomembrane system includes the • nuclear envelope, • endoplasmic reticulum (ER), • Golgi apparatus, • lysosomes, • vacuoles, and • plasma membrane.
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4.7 Many organelles are connected in the endomembrane system
• The largest component of the endomembrane system is the endoplasmic reticulum (ER), an extensive network of flattened sacs and tubules.
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4.8 The endoplasmic reticulum is a biosynthetic workshop
• There are two kinds of endoplasmic reticulum, which differ in structure and function.
1. Smooth ER lacks attached ribosomes. 2. Rough ER has bound ribosomes that stud the
outer surface of the membrane.
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Figure 4.8a
Rough ER
Smooth ER
Ribosomes
Rough ERSmooth ER
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Figure 4.8b
mRNA
1
2
3
4
Bound ribosome
Transport vesiclebuds off
Secretoryproteininside trans-port vesicle
Sugar chain
Rough ER
GlycoproteinGrowing polypeptide
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4.8 The endoplasmic reticulum is a biosynthetic workshop
• Smooth ER is involved in a variety of metabolic processes, including
• the production of enzymes important in the synthesis of lipids, oils, phospholipids, and steroids,
• the production of enzymes that help process drugs, alcohol, and other potentially harmful substances, and
• the storage of calcium ions.
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4.8 The endoplasmic reticulum is a biosynthetic workshop
• Rough ER makes • additional membrane for itself and • secretory proteins.
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4.9 The Golgi apparatus modifies, sorts, and ships cell products
• The Golgi apparatus serves as a molecular warehouse and processing station for products manufactured by the ER.
• Products travel in transport vesicles from the ER to the Golgi apparatus.
• One side of the Golgi stack serves as a receiving dock for transport vesicles produced by the ER.
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4.9 The Golgi apparatus modifies, sorts, and ships cell products
• Products of the ER are modified as a Golgi sac progresses through the stack.
• The “shipping” side of the Golgi functions as a depot, where products in vesicles bud off and travel to other sites.
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Figure 4.9
Golgi apparatus
1
2
3
4
“Receiving” side of Golgi apparatusTransport vesiclefrom the ER
Transportvesicle from the Golgi
“Shipping” side of Golgi apparatus
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4.10 Lysosomes are digestive compartments within a cell
• A lysosome is a membrane-enclosed sac of digestive enzymes
• made by rough ER and • processed in the Golgi apparatus
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4.10 Lysosomes are digestive compartments within a cell
• Lysosomes • fuse with food vacuoles and digest food, • destroy bacteria engulfed by white blood cells, or • fuse with other vesicles containing damaged
organelles or other materials to be recycled within a cell.
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Animation: Lysosome Formation
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Figure 4.10a-1
Digestive enzymes
Lysosome
Plasma membrane
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Figure 4.10a-2
Digestive enzymes
Lysosome
Food vacuole
Plasma membrane
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Figure 4.10a-3
Digestive enzymes
Lysosome
Food vacuole
Plasma membrane
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Figure 4.10a-4
Digestive enzymes
Lysosome
Food vacuole
Plasma membrane
Digestion
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Figure 4.10b-1
Lysosome
Vesicle containingdamaged mitochondrion
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Figure 4.10b-2
Lysosome
Vesicle containingdamaged mitochondrion
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Figure 4.10b-3
Lysosome
DigestionVesicle containingdamaged mitochondrion
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4.11 Vacuoles function in the general maintenance of the cell
• Vacuoles are large vesicles that have a variety of functions.
• Some protists have contractile vacuoles, which help to eliminate water from the protist.
• In plants, vacuoles may • have digestive functions, • contain pigments, or • contain poisons that protect the plant.
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Video: Paramecium Vacuole
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Figure 4.11a
Contractile vacuoles
Nucleus
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Figure 4.11b
Central vacuole
Chloroplast
Nucleus
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4.12 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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Figure 4.12
Nucleus
Smooth ER
Rough ER
Transport vesicle
Lysosome
Nuclear envelope
Golgi apparatus
Plasma membrane
Transportvesicle
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4.12 A review of the structures involved in manufacturing and breakdown
• Peroxisomes are metabolic compartments that do not originate from the endomembrane system.
• How they are related to other organelles is still unknown.
• Some peroxisomes break down fatty acids to be used as cellular fuel.
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ENERGY-CONVERTING ORGANELLES
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4.13 Mitochondria harvest chemical energy from food
• Mitochondria are organelles that carry out cellular respiration in nearly all eukaryotic cells.
• Cellular respiration converts the chemical energy in foods to chemical energy in ATP (adenosine triphosphate).
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4.13 Mitochondria harvest chemical energy from food
• Mitochondria have two internal compartments. 1. The intermembrane space is the narrow region
between the inner and outer membranes. 2. The mitochondrial matrix contains
• the mitochondrial DNA, • ribosomes, and • many enzymes that catalyze some of the reactions of
cellular respiration.
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4.13 Mitochondria harvest chemical energy from food
• Folds of the inner mitochondrial membrane, called cristae, increase the membrane’s surface area, enhancing the mitochondrion’s ability to produce ATP.
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Figure 4.13
Mitochondrion
Intermembrane space
Outer membrane
Inner membrane
CristaMatrix
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4.14 Chloroplasts convert solar energy to chemical energy
• Photosynthesis is the conversion of light energy from the sun to the chemical energy of sugar molecules.
• Chloroplasts are the photosynthesizing organelles of plants and algae.
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4.14 Chloroplasts convert solar energy to chemical energy
• Chloroplasts are partitioned into compartments. • Between the outer and inner membrane is a thin
intermembrane space. • Inside the inner membrane is a thick fluid called
stroma, which contains the chloroplast DNA, ribosomes, many enzymes, and a network of interconnected sacs called thylakoids, where green chlorophyll molecules trap solar energy.
• In some regions, thylakoids are stacked like poker chips. Each stack is called a granum.
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Figure 4.14
Chloroplast
Granum
Stroma
Inner and outer membranes
Thylakoid
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4.15 EVOLUTION CONNECTION: Mitochondria and chloroplasts evolved by endosymbiosis
• Mitochondria and chloroplasts contain • DNA and • ribosomes.
• The structure of this DNA and these ribosomes is very similar to that found in prokaryotic cells.
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4.15 EVOLUTION CONNECTION: Mitochondria and chloroplasts evolved by endosymbiosis
• The endosymbiont theory states that • mitochondria and chloroplasts were formerly small
prokaryotes and • they began living within larger cells.
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Figure 4.15Endoplasmic reticulum
Nucleus
Ancestor ofeukaryotic cells (host cell)
Mitochondrion
Engulfing of photosynthetic prokaryote
Mitochondrion
Photosynthetic eukaryote
Chloroplast
Nonphotosynthetic eukaryote
At leastone cell
Engulfing of oxygen- using prokaryote
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Figure 4.15-1Endoplasmic reticulum
Nucleus
Ancestor ofeukaryotic cells (host cell)
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Figure 4.15-2Endoplasmic reticulum
Nucleus
Ancestor ofeukaryotic cells (host cell)
Mitochondrion
Nonphotosynthetic eukaryote
Engulfing of oxygen- using prokaryote
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Figure 4.15-3Endoplasmic reticulum
Nucleus
Ancestor ofeukaryotic cells (host cell)
Mitochondrion
Engulfing of photosynthetic prokaryote
Mitochondrion
Photosynthetic eukaryote
Chloroplast
Nonphotosynthetic eukaryote
At leastone cell
Engulfing of oxygen- using prokaryote
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THE CYTOSKELETON AND CELL SURFACES
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4.16 The cell’s internal skeleton helps organize its structure and activities
• Cells contain a network of protein fibers, called the cytoskeleton, which organize the structures and activities of the cell.
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Video: Cytoplasmic Streaming
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4.16 The cell’s internal skeleton helps organize its structure and activities
• Microtubules (made of tubulin) • shape and support the cell and • act as tracks along which organelles equipped with
motor proteins move. • In animal cells, microtubules grow out from a region
near the nucleus called the centrosome, which contains a pair of centrioles, each composed of a ring of microtubules.
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4.16 The cell’s internal skeleton helps organize its structure and activities
• Intermediate filaments • are found in the cells of most animals, • reinforce cell shape and anchor some organelles,
and • are often more permanent fixtures in the cell.
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4.16 The cell’s internal skeleton helps organize its structure and activities
• Microfilaments (actin filaments) • support the cell’s shape and • are involved in motility.
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Figure 4.16-0
Nucleus
Nucleus
Microtubule
25 nmIntermediate filament
10 nm
Microfilament
7 nm
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Figure 4.16-1
Nucleus
Microtubule
25 nm
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Figure 4.16-2
Nucleus
Intermediate filament
10 nm
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Figure 4.16-3
Microfilament
7 nm
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Figure 4.16-4
Nucleus
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Figure 4.16-5
Nucleus
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Figure 4.16-6
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4.17 SCIENTIFIC THINKING: Scientists discovered the cytoskeleton using the tools of biochemistry and microscopy
• In the 1940s, biochemists first isolated and identified the proteins actin and myosin from muscle cells.
• In 1954, scientists, using newly developed techniques of microscopy, established how filaments of actin and myosin interact in muscle contraction.
• In the next decade, researchers identified actin filaments in all types of cells.
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4.17 SCIENTIFIC THINKING: Scientists discovered the cytoskeleton using the tools of biochemistry and microscopy
• In the 1970s, scientists were able to visualize actin filaments using fluorescent tags and in living cells.
• In the 1980s, biologists were able to record the changing architecture of the cytoskeleton.
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Figure 4.17
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4.18 Cilia and flagella move when microtubules bend
• The short, numerous appendages that propel protists such as Paramecium are called cilia (singular, cilium).
• Other protists may move using flagella, which are longer than cilia and usually limited to one or a few per cell.
• Some cells of multicellular organisms also have cilia or flagella.
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Video: Paramecium Cilia
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Video: Chlamydomonas
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Figure 4.18a
Cilia
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Figure 4.18b
Flagellum
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4.18 Cilia and flagella move when microtubules bend
• A flagellum, longer than cilia, propels a cell by an undulating, whiplike motion.
• Cilia work more like the oars of a boat. • Although differences exist, flagella and cilia have a
common structure and mechanism of movement.
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4.18 Cilia and flagella move when microtubules bend
• Both flagella and cilia are composed of microtubules wrapped in an extension of the plasma membrane.
• In nearly all eukaryotic cilia and flagella, a ring of nine microtubule doublets surrounds a central pair of microtubules.
• This arrangement is called the 9 + 2 pattern. • The microtubule assembly is anchored in a basal
body with nine microtubule triplets arranged in a ring.
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Animation: Cilia and Flagella
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Figure 4.18c-0
Outer microtubule doublet
Central microtubules
Cross-linkingproteinsMotor proteins (dyneins)
Plasma membrane
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Figure 4.18c-1
Outer microtubule doublet
Central microtubules
Cross-linkingproteinsMotor proteins (dyneins)
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Figure 4.18c-2
Outer microtubule doublet
Central microtubules
Cross-linkingproteinsMotor proteins (dyneins)
Plasma membrane
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4.18 Cilia and flagella move when microtubules bend
• Cilia and flagella move by bending motor proteins called dynein feet.
• These feet attach to and exert a sliding force on an adjacent doublet.
• This “walking” causes the microtubules to bend.
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4.19 The extracellular matrix of animal cells functions in support and regulation
• Animal cells synthesize and secrete an elaborate extracellular matrix (ECM), which
• helps hold cells together in tissues and • protects and supports the plasma membrane.
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4.19 The extracellular matrix of animal cells functions in support and regulation
• The ECM may attach to the cell through other glycoproteins that then bind to membrane proteins called integrins.
• Integrins • span the membrane and • attach on the other side to proteins connected to
microfilaments of the cytoskeleton.
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Figure 4.19
Collagen fiber
EXTRACELLULAR FLUID
CYTOPLASM
Glycoproteincomplex with long polysaccharide
Connectingglycoprotein
Integrin
Plasma membrane
Microfilaments of cytoskeleton
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4.20 Three types of cell junctions are found in animal tissues
• Adjacent cells adhere, interact, and communicate through specialized junctions between them.
• Tight junctions prevent leakage of fluid across a layer of epithelial cells.
• Anchoring junctions fasten cells together into sheets.
• Gap junctions are channels that allow small molecules to flow through protein-lined pores between cells.
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Animation: Desmosomes
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Animation: Gap Junctions
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Animation: Tight Junctions
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Figure 4.20
Tight junction
Anchoringjunction
Gap junction
Plasma membranesof adjacent cells
Ions or small molecules Extracellular matrix
Tight junctions prevent fluid from moving across alayer of cells
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4.21 Cell walls enclose and support plant cells
• A plant cell, but not an animal cell, has a rigid cell wall that
• protects and provides skeletal support that helps keep the plant upright and
• is primarily composed of cellulose. • Plant cells have cell junctions called
plasmodesmata that allow plants tissues to share • water, • nourishment, and • chemical messages.
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Figure 4.21
Vacuole
Plant cellwalls
Plasmodesmata
Primary cell wallSecondary cell wallPlasma membrane
Cytosol
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4.22 Review: Eukaryotic cell structures can be grouped on the basis of four main functions
• Eukaryotic cell structures can be grouped on the basis of four functions:
1. genetic control, 2. manufacturing, distribution, and breakdown of
materials, 3. energy processing, and 4. structural support, movement, and intercellular
communication.
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Table 4-22-0
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Table 4-22-1
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Table 4-22-2
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You should now be able to
1. Describe the importance of microscopes in understanding cell structure and function.
2. Describe the two parts of cell theory. 3. Distinguish between the structures of prokaryotic
and eukaryotic cells. 4. Explain how cell size is limited. 5. Describe the structure and functions of cell
membranes.
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You should now be able to
6. Explain why compartmentalization is important in eukaryotic cells.
7. Compare the structures of plant and animal cells. Note the function of each cell part.
8. Compare the structures and functions of chloroplasts and mitochondria.
9. Describe the evidence that suggests that mitochondria and chloroplasts evolved by endosymbiosis.
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You should now be able to
10. Compare the structures and functions of microfilaments, intermediate filaments, and microtubules.
11. Relate the structure of cilia and flagella to their functions.
12. Relate the structure of the extracellular matrix to its functions.
13. Compare the structures and functions of tight junctions, anchoring junctions, and gap junctions.
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You should now be able to
14. Relate the structures of plant cell walls and plasmodesmata to their functions.
15. Describe the four functional categories of organelles in eukaryotic cells.
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Table 4-1
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Figure 4.UN02
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Figure 4.UN03
a. b.c.
d.
e.
f.
g.
h.
i.
j.k.
l.
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Figure 4.UN04-0
Poles of dividing cell
Mark
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Figure 4.UN04-1
Poles of dividing cell
Mark
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Figure 4.UN04-2