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Semelhante a Biology in Focus Chapter 4 (20)
Biology in Focus Chapter 4
- 1. CAMPBELL BIOLOGY IN FOCUS
© 2014 Pearson Education, Inc.
Urry • Cain • Wasserman • Minorsky • Jackson • Reece
Lecture Presentations by
Kathleen Fitzpatrick and Nicole Tunbridge
4
A Tour of
the Cell
- 2. Overview: The Fundamental Units of Life
All organisms are made of cells
The cell is the simplest collection of matter
that can be alive
All cells are related by their descent from earlier
cells
Though cells can differ substantially from one
another, they share common features
© 2014 Pearson Education, Inc.
- 4. Concept 4.1: Biologists use microscopes and the
tools of biochemistry to study cells
Most cells are between 1 and 100 µm in diameter,
too small to be seen by the unaided eye
© 2014 Pearson Education, Inc.
- 5. Microscopy
Scientists use microscopes to visualize cells too
small to see with the naked eye
In a light microscope (LM), visible light is passed
through a specimen and then through glass lenses
Lenses refract (bend) the light, so that the image is
magnified
© 2014 Pearson Education, Inc.
- 6. Three important parameters of microscopy
Magnification, the ratio of an object’s image
size to its real size
Resolution, the measure of the clarity of the
image, or the minimum distance between two
distinguishable points
Contrast, visible differences in parts of the
sample
© 2014 Pearson Education, Inc.
- 7. © 2014 Pearson Education, Inc.
Figure 4.2
Most plant and
animal cells
Length of some
nerve and
muscle cells
Viruses
Smallest bacteria
Human height
Chicken egg
Frog egg
Human egg
Nucleus
Most bacteria
Mitochondrion
Super-
resolution
microscopy
Atoms
Small molecules
Ribosomes
Proteins
Lipids
Unaidedeye
LM
10 m
EM
1 m
0.1 m
1 cm
1 mm
100 µm
10 nm
1 nm
0.1 nm
100 nm
10 µm
1 µm
- 8. © 2014 Pearson Education, Inc.
Figure 4.2a
Length of some
nerve and
muscle cells
Human height
Chicken egg
Frog egg
Human egg Unaidedeye
LM
10 m
1 m
0.1 m
1 cm
1 mm
100 µm
- 9. © 2014 Pearson Education, Inc.
Figure 4.2b
Most plant and
animal cells
Viruses
Smallest bacteria
Nucleus
Most bacteria
Mitochondrion
Super-
resolution
microscopy
Atoms
Small molecules
Ribosomes
Proteins
Lipids
EM
100 µm
10 nm
1 nm
0.1 nm
100 nm
10 µm
1 µm
LM
- 10. LMs can magnify effectively to about 1,000 times the
size of the actual specimen
Various techniques enhance contrast and enable cell
components to be stained or labeled
Most subcellular structures, including organelles
(membrane-enclosed compartments), are too small
to be resolved by light microscopy
© 2014 Pearson Education, Inc.
- 11. Two basic types of electron microscopes (EMs) are
used to study subcellular structures
Scanning electron microscopes (SEMs) focus a
beam of electrons onto the surface of a specimen,
providing images that look three-dimensional
Transmission electron microscopes (TEMs) focus
a beam of electrons through a specimen
TEM is used mainly to study the internal structure
of cells
© 2014 Pearson Education, Inc.
- 12. © 2014 Pearson Education, Inc.
Figure 4.3
Scanning electron
microscopy (SEM)
Transmission electron
microscopy (TEM)
Longitudinal section
of cilium
Cross section
of cilium
Cilia
2 µm
2 µm
50µm
10µm50µm
Brightfield
(unstained specimen)
Electron Microscopy (EM)
Fluorescence
Brightfield
(stained specimen)
Differential-interference
contrast (Nomarski)
Phase-contrast
Confocal
Light Microscopy (LM)
- 13. © 2014 Pearson Education, Inc.
Figure 4.3a
50µm
Brightfield
(unstained specimen)
Brightfield
(stained specimen)
Differential-interference
contrast (Nomarski)
Phase-contrast
Light Microscopy (LM)
- 14. © 2014 Pearson Education, Inc.
Figure 4.3aa
50µm
Brightfield
(unstained specimen)
- 15. © 2014 Pearson Education, Inc.
Figure 4.3ab
Brightfield
(stained specimen)
50µm
- 17. © 2014 Pearson Education, Inc.
Figure 4.3ad
Differential-interference
contrast (Nomarski)
50µm
- 18. © 2014 Pearson Education, Inc.
Figure 4.3b
50µm
10µm
Fluorescence Confocal
Light Microscopy (LM)
- 20. © 2014 Pearson Education, Inc.
Figure 4.3bb
Confocal: without technique
50µm
- 21. © 2014 Pearson Education, Inc.
Figure 4.3bc
Confocal: with technique
50µm
- 22. © 2014 Pearson Education, Inc.
Figure 4.3c
Scanning electron
microscopy (SEM)
Transmission electron
microscopy (TEM)
Longitudinal section
of cilium
Cross section
of cilium
Cilia
2 µm
Electron Microscopy (EM)
- 23. © 2014 Pearson Education, Inc.
Figure 4.3ca
Scanning electron
microscopy (SEM)
Cilia
2 µm
- 24. © 2014 Pearson Education, Inc.
Figure 4.3cb
Transmission electron
microscopy (TEM)
Longitudinal section
of cilium
Cross section
of cilium
2 µm
- 25. Recent advances in light microscopy
Labeling molecules or structures with fluorescent
markers improves visualization of details
Confocal and other types of microscopy have
sharpened images of tissues and cells
New techniques and labeling have improved
resolution so that structures as small as 10–20 µm
can be distinguished
© 2014 Pearson Education, Inc.
- 26. Cell Fractionation
Cell fractionation breaks up cells and separates the
components, using centrifugation
Cell components separate based on their
relative size
Cell fractionation enables scientists to determine the
functions of organelles
Biochemistry and cytology help correlate cell function
with structure
© 2014 Pearson Education, Inc.
- 27. Concept 4.2: Eukaryotic cells have internal
membranes that compartmentalize their functions
The basic structural and functional unit of every
organism is one of two types of cells: prokaryotic or
eukaryotic
Organisms of the domains Bacteria and Archaea
consist of prokaryotic cells
Protists, fungi, animals, and plants all consist of
eukaryotic cells
© 2014 Pearson Education, Inc.
- 28. Comparing Prokaryotic and Eukaryotic Cells
Basic features of all cells
Plasma membrane
Semifluid substance called cytosol
Chromosomes (carry genes)
Ribosomes (make proteins)
© 2014 Pearson Education, Inc.
- 29. Prokaryotic cells are characterized by having
No nucleus
DNA in an unbound region called the nucleoid
No membrane-bound organelles
Cytoplasm bound by the plasma membrane
© 2014 Pearson Education, Inc.
- 30. © 2014 Pearson Education, Inc.
Figure 4.4
(a) A typical rod-shaped
bacterium
0.5 µm
(b) A thin section through
the bacterium Bacillus
coagulans (TEM)
Bacterial
chromosome
Fimbriae
Nucleoid
Ribosomes
Cell wall
Plasma membrane
Capsule
Flagella
- 31. © 2014 Pearson Education, Inc.
Figure 4.4a
0.5 µm
(b) A thin section through
the bacterium Bacillus
coagulans (TEM)
Nucleoid
Ribosomes
Cell wall
Plasma membrane
Capsule
- 32. Eukaryotic cells are characterized by having
DNA in a nucleus that is bounded by a membranous
nuclear envelope
Membrane-bound organelles
Cytoplasm in the region between the plasma
membrane and nucleus
Eukaryotic cells are generally much larger than
prokaryotic cells
© 2014 Pearson Education, Inc.
- 33. The plasma membrane is a selective barrier that
allows sufficient passage of oxygen, nutrients, and
waste to service the volume of every cell
The general structure of a biological membrane is
a double layer of phospholipids
© 2014 Pearson Education, Inc.
- 34. © 2014 Pearson Education, Inc.
Figure 4.5
0.1 µm
(a) TEM of a plasma
membraneOutside of cell
(b) Structure of the plasma membrane
Inside
of cell
Hydrophilic
region
Hydrophilic
region
Hydrophobic
region
Carbohydrate side chains
Phospholipid Proteins
- 35. © 2014 Pearson Education, Inc.
Figure 4.5a
0.1 µm
(a) TEM of a plasma
membrane
Outside of cell
Inside
of cell
- 36. © 2014 Pearson Education, Inc.
Figure 4.5b
(b) Structure of the plasma membrane
Hydrophilic
region
Hydrophilic
region
Hydrophobic
region
Carbohydrate side chains
Phospholipid Proteins
- 37. Metabolic requirements set upper limits on the size
of cells
The ratio of surface area to volume of a cell is critical
As the surface area increases by a factor of n2
, the
volume increases by a factor of n3
Small cells have a greater surface area relative
to volume
© 2014 Pearson Education, Inc.
- 38. © 2014 Pearson Education, Inc.
Figure 4.6
750
Surface area increases while
total volume remains constant
125
150
125
6
1
6
1
61.2
5
1
Total surface area
[sum of the surface areas
(height × width) of all box
sides × number of boxes]
Total volume
[height × width × length
× number of boxes]
Surface-to-volume
ratio
[surface area ÷ volume]
- 39. A Panoramic View of the Eukaryotic Cell
A eukaryotic cell has internal membranes that
divide the cell into compartments—organelles
The plasma membrane and organelle
membranes participate directly in the cell’s
metabolism
© 2014 Pearson Education, Inc.
Animation: Tour of a Plant Cell
Animation: Tour of an Animal Cell
- 40. © 2014 Pearson Education, Inc.
Figure 4.7a
CYTOSKELETON:
NUCLEUS
ENDOPLASMIC RETICULUM (ER)
Smooth ER
Rough ERFlagellum
Centrosome
Microfilaments
Intermediate
filaments
Microvilli
Microtubules
Mitochondrion
Peroxisome
Golgi apparatus
Lysosome
Plasma
membrane
Ribosomes
Nucleolus
Nuclear
envelope
Chromatin
- 41. © 2014 Pearson Education, Inc.
Figure 4.7b
CYTO-
SKELETON
NUCLEUS
Smooth endoplasmic
reticulum
Chloroplast
Central vacuole
Microfilaments
Intermediate
filaments
Cell wall
Microtubules
Mitochondrion
Peroxisome
Golgi
apparatus
Plasmodesmata
Plasma membrane
Ribosomes
Nucleolus
Nuclear envelope
Chromatin
Wall of adjacent cell
Rough endoplasmic
reticulum
- 42. © 2014 Pearson Education, Inc.
Figure 4.7c
Nucleolus
Nucleus
Cell
10µm
Human cells from lining of uterus
(colorized TEM)
- 43. © 2014 Pearson Education, Inc.
Figure 4.7d
5µm
Parent
cell
Buds
Yeast cells budding (colorized SEM)
- 44. © 2014 Pearson Education, Inc.
Figure 4.7e
1 µm
A single yeast cell (colorized TEM)
Mitochondrion
Nucleus
Vacuole
Cell wall
- 45. © 2014 Pearson Education, Inc.
Figure 4.7f
5µm
Cell wall
Cell
Chloroplast
Mitochondrion
Nucleus
Nucleolus
Cells from duckweed (colorized TEM)
- 46. © 2014 Pearson Education, Inc.
Figure 4.7g
8µm
Chlamydomonas
(colorized SEM)
- 47. © 2014 Pearson Education, Inc.
Figure 4.7h
1µm
Chlamydomonas (colorized TEM)
Cell wall
Flagella
Chloroplast
Vacuole
Nucleus
Nucleolus
- 48. Concept 4.3: The eukaryotic cell’s genetic
instructions are housed in the nucleus and carried
out by the ribosomes
The nucleus contains most of the DNA in a
eukaryotic cell
Ribosomes use the information from the DNA to
make proteins
© 2014 Pearson Education, Inc.
- 49. The Nucleus: Information Central
The nucleus contains most of the cell’s genes and
is usually the most conspicuous organelle
The nuclear envelope encloses the nucleus,
separating it from the cytoplasm
The nuclear membrane is a double membrane;
each membrane consists of a lipid bilayer
© 2014 Pearson Education, Inc.
- 50. Pores regulate the entry and exit of molecules from
the nucleus
The shape of the nucleus is maintained by the
nuclear lamina, which is composed of protein
© 2014 Pearson Education, Inc.
- 51. © 2014 Pearson Education, Inc.
Figure 4.8
Ribosome
1 µm
Chromatin
Rough ER
Nucleus
Nucleolus
Nucleus
Chromatin
0.5µm
0.25µm
Nuclear envelope:
Nuclear pore
Inner membrane
Outer membrane
Pore
complex
Close-up
of nuclear
envelope
Nuclear lamina (TEM)
Surface of nuclear
envelope
Pore complexes (TEM)
- 52. © 2014 Pearson Education, Inc.
Figure 4.8a
Ribosome
Chromatin
Rough ER
Nucleus
Nucleolus
Chromatin
Nuclear envelope:
Nuclear pore
Inner membrane
Outer membrane
Pore
complex
Close-up
of nuclear
envelope
- 53. © 2014 Pearson Education, Inc.
Figure 4.8b
1 µm
Nuclear envelope:
Nuclear pore
Inner membrane
Outer membrane
Surface of nuclear envelope
- 54. © 2014 Pearson Education, Inc.
Figure 4.8c
0.25µm
Pore complexes (TEM)
- 55. © 2014 Pearson Education, Inc.
Figure 4.8d
0.5µm
Nuclear lamina (TEM)
- 56. In the nucleus, DNA is organized into discrete units
called chromosomes
Each chromosome is one long DNA molecule
associated with proteins
The DNA and proteins of chromosomes are together
called chromatin
Chromatin condenses to form discrete
chromosomes as a cell prepares to divide
The nucleolus is located within the nucleus and is
the site of ribosomal RNA (rRNA) synthesis
© 2014 Pearson Education, Inc.
- 57. Ribosomes: Protein Factories
Ribosomes are complexes of ribosomal RNA and
protein
Ribosomes carry out protein synthesis in two
locations
In the cytosol (free ribosomes)
On the outside of the endoplasmic reticulum or the
nuclear envelope (bound ribosomes)
© 2014 Pearson Education, Inc.
- 58. © 2014 Pearson Education, Inc.
Figure 4.9
TEM showing ER and ribosomes Diagram of a ribosome
Ribosomes bound to ER
Free ribosomes in cytosol
Endoplasmic reticulum (ER)
Ribosomes
ER
0.25 µm
Large
subunit
Small
subunit
- 59. © 2014 Pearson Education, Inc.
Figure 4.9a
TEM showing ER and ribosomes
Ribosomes bound to ER
Free ribosomes in cytosol
Endoplasmic reticulum (ER)
0.25 µm
- 60. Concept 4.4: The endomembrane system
regulates protein traffic and performs metabolic
functions in the cell
Components of the endomembrane system
Nuclear envelope
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Plasma membrane
These components are either continuous or
connected through transfer by vesicles
© 2014 Pearson Education, Inc.
- 61. The Endoplasmic Reticulum: Biosynthetic Factory
The endoplasmic reticulum (ER) accounts for
more than half of the total membrane in many
eukaryotic cells
The ER membrane is continuous with the nuclear
envelope
There are two distinct regions of ER
Smooth ER: lacks ribosomes
Rough ER: surface is studded with ribosomes
© 2014 Pearson Education, Inc.
Video: Endoplasmic Reticulum
Video: ER and Mitochondria
- 62. © 2014 Pearson Education, Inc.
Figure 4.10
Transport vesicle
Smooth ER
Rough
ER
Ribosomes Transitional
ER
Cisternae
ER lumen
Smooth ER Rough ER
Nuclear
envelope
0.2 µm
- 63. © 2014 Pearson Education, Inc.
Figure 4.10a
Transport vesicle
Smooth ER
Rough
ER
Ribosomes Transitional
ER
Cisternae
ER lumen
Nuclear
envelope
- 64. © 2014 Pearson Education, Inc.
Figure 4.10b
Smooth ER Rough ER
0.2 µm
- 65. Functions of Smooth ER
The smooth ER
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies drugs and poisons
Stores calcium ions
© 2014 Pearson Education, Inc.
- 66. Functions of Rough ER
The rough ER
Has bound ribosomes, which secrete glycoproteins
(proteins covalently bonded to carbohydrates)
Distributes transport vesicles, proteins surrounded
by membranes
Is a membrane factory for the cell
© 2014 Pearson Education, Inc.
- 67. The Golgi apparatus consists of flattened
membranous sacs called cisternae
Functions of the Golgi apparatus
Modifies products of the ER
Manufactures certain macromolecules
Sorts and packages materials into transport vesicles
The Golgi Apparatus: Shipping and Receiving
Center
© 2014 Pearson Education, Inc.
Video: Golgi 3-D
Video: Golgi Secretion
Video: ER to Golgi Traffic
- 68. © 2014 Pearson Education, Inc.
Figure 4.11
TEM of Golgi apparatus
Golgi
apparatus
trans face
(“shipping”
side of Golgi
apparatus)
Cisternae
0.1 µm
cis face
(“receiving” side of
Golgi apparatus)
- 69. © 2014 Pearson Education, Inc.
Figure 4.11a
trans face
(“shipping”
side of Golgi
apparatus)
Cisternae
cis face
(“receiving” side of
Golgi apparatus)
- 70. © 2014 Pearson Education, Inc.
Figure 4.11b
TEM of Golgi apparatus
0.1 µm
- 71. Lysosomes: Digestive Compartments
A lysosome is a membranous sac of hydrolytic
enzymes that can digest macromolecules
Lysosomal enzymes can hydrolyze proteins, fats,
polysaccharides, and nucleic acids
Lysosomal enzymes work best in the acidic
environment inside the lysosome
© 2014 Pearson Education, Inc.
- 72. Animation: Lysosome Formation
Video: Phagocytosis
Some types of cell can engulf another cell by
phagocytosis; this forms a food vacuole
A lysosome fuses with the food vacuole and digests
the molecules
Lysosomes also use enzymes to recycle the cell’s
own organelles and macromolecules, a process
called autophagy
© 2014 Pearson Education, Inc.
Video: Paramecium Vacuole
- 73. © 2014 Pearson Education, Inc.
Figure 4.12
Lysosome
1 µmNucleus
Lysosome
Digestive
enzymes
Plasma
membrane
Food vacuole
Lysosomes: Phagocytosis
Digestion
- 74. © 2014 Pearson Education, Inc.
Figure 4.12a
Lysosome
Digestive
enzymes
Plasma
membrane
Food vacuole
Lysosomes: Phagocytosis
Digestion
- 76. © 2014 Pearson Education, Inc.
Figure 4.13
Lysosome
Lysosomes: Autophagy
Peroxisome
Mitochondrion
Vesicle
Digestion
Mitochondrion
fragment
Peroxisome
fragment
Vesicle containing two
damaged organelles
1 µm
- 77. © 2014 Pearson Education, Inc.
Figure 4.13a
Lysosome
Lysosomes: Autophagy
Peroxisome
Mitochondrion
Vesicle
Digestion
- 78. © 2014 Pearson Education, Inc.
Figure 4.13b
Mitochondrion
fragment
Peroxisome
fragment
Vesicle containing two
damaged organelles
1 µm
- 79. Vacuoles: Diverse Maintenance Compartments
Vacuoles are large vesicles derived from the
endoplasmic reticulum and Golgi apparatus
© 2014 Pearson Education, Inc.
- 80. Food vacuoles are formed by phagocytosis
Contractile vacuoles, found in many freshwater
protists, pump excess water out of cells
Central vacuoles, found in many mature plant cells,
hold organic compounds and water
Certain vacuoles in plants and fungi carry out
enzymatic hydrolysis like lysosomes
© 2014 Pearson Education, Inc.
- 81. © 2014 Pearson Education, Inc.
Figure 4.14
Central vacuole
Central
vacuole
Chloroplast
Cytosol
Cell wall
Nucleus
Plant cell vacuole 5 µm
- 82. © 2014 Pearson Education, Inc.
Figure 4.14a
Central
vacuole
Chloroplast
Cytosol
Cell wall
Nucleus
Plant cell vacuole 5 µm
- 83. The Endomembrane System: A Review
The endomembrane system is a complex and
dynamic player in the cell’s compartmental
organization
© 2014 Pearson Education, Inc.
- 84. © 2014 Pearson Education, Inc.
Figure 4.15-1
Rough ER
Nucleus
Smooth ER
Plasma
membrane
- 85. © 2014 Pearson Education, Inc.
Figure 4.15-2
Plasma
membrane
Rough ER
cis Golgi
Nucleus
Smooth ER
trans Golgi
- 86. © 2014 Pearson Education, Inc.
Figure 4.15-3
Plasma
membrane
Rough ER
cis Golgi
Nucleus
Smooth ER
trans Golgi
- 87. Concept 4.5: Mitochondria and chloroplasts
change energy from one form to another
Mitochondria are the sites of cellular respiration, a
metabolic process that uses oxygen to generate ATP
Chloroplasts, found in plants and algae, are the
sites of photosynthesis
Peroxisomes are oxidative organelles
© 2014 Pearson Education, Inc.
- 88. Mitochondria and chloroplasts have similarities
with bacteria
Enveloped by a double membrane
Contain free ribosomes and circular DNA molecules
Grow and reproduce somewhat independently in cells
The Evolutionary Origins of Mitochondria and
Chloroplasts
© 2014 Pearson Education, Inc.
- 89. The endosymbiont theory
An early ancestor of eukaryotic cells engulfed a
nonphotosynthetic prokaryotic cell, which formed an
endosymbiont relationship with its host
The host cell and endosymbiont merged into a single
organism, a eukaryotic cell with a mitochondrion
At least one of these cells may have taken up a
photosynthetic prokaryote, becoming the ancestor of
cells that contain chloroplasts
© 2014 Pearson Education, Inc.
Video: ER and Mitochondria
Video: Mitochondria 3-D
- 90. © 2014 Pearson Education, Inc.
Figure 4.16
Mitochondrion
Mitochondrion
Nonphotosynthetic
eukaryote
Photosynthetic eukaryote
At least
one cell Chloroplast
Engulfing of
photosynthetic
prokaryote
Nucleus
Nuclear
envelope
Endoplasmic
reticulum
Ancestor of
eukaryotic cells
(host cell)
Engulfing of oxygen-
using nonphotosynthetic
prokaryote, which
becomes a mitochondrion
- 91. Mitochondria: Chemical Energy Conversion
Mitochondria are in nearly all eukaryotic cells
They have a smooth outer membrane and an inner
membrane folded into cristae
The inner membrane creates two compartments:
intermembrane space and mitochondrial matrix
Some metabolic steps of cellular respiration are
catalyzed in the mitochondrial matrix
Cristae present a large surface area for enzymes
that synthesize ATP
© 2014 Pearson Education, Inc.
- 92. © 2014 Pearson Education, Inc.
Figure 4.17
Free
ribosomes
in the
mitochondrial
matrix
Mitochondrion
Intermembrane space
Matrix
Cristae
DNA
Outer
membrane
Inner
membrane
0.1 µm
- 93. © 2014 Pearson Education, Inc.
Figure 4.17a
Matrix
Cristae
Outer
membrane
Inner
membrane
0.1 µm
- 94. Chloroplasts: Capture of Light Energy
Chloroplasts contain the green pigment chlorophyll,
as well as enzymes and other molecules that
function in photosynthesis
Chloroplasts are found in leaves and other green
organs of plants and in algae
© 2014 Pearson Education, Inc.
- 95. Chloroplast structure includes
Thylakoids, membranous sacs, stacked to form
a granum
Stroma, the internal fluid
The chloroplast is one of a group of plant organelles
called plastids
© 2014 Pearson Education, Inc.
- 96. © 2014 Pearson Education, Inc.
Figure 4.18
Intermembrane space
Ribosomes
Inner and outer
membranes
1 µm
Stroma
Granum
DNA
Chloroplast
Thylakoid
(a) Diagram and TEM of chloroplast
50 µm
(b) Chloroplasts in an algal cell
Chloroplasts
(red)
- 97. © 2014 Pearson Education, Inc.
Figure 4.18a
Intermembrane space
Ribosomes
Inner and outer
membranes
1 µm
Stroma
Granum
DNA
Thylakoid
(a) Diagram and TEM of chloroplast
- 98. © 2014 Pearson Education, Inc.
Figure 4.18aa
Inner and outer
membranes
1 µm
Stroma
Granum
- 99. © 2014 Pearson Education, Inc.
Figure 4.18b
50 µm
(b) Chloroplasts in an algal cell
Chloroplasts
(red)
- 100. Peroxisomes: Oxidation
Peroxisomes are specialized metabolic
compartments bounded by a single membrane
Peroxisomes produce hydrogen peroxide and
convert it to water
Peroxisomes perform reactions with many different
functions
© 2014 Pearson Education, Inc.
Video: Cytoskeleton in Neuron
- 101. © 2014 Pearson Education, Inc.
Figure 4.19
Chloroplast
1 µm
Peroxisome
Mitochondrion
- 102. Concept 4.6: The cytoskeleton is a network of
fibers that organizes structures and activities in
the cell
The cytoskeleton is a network of fibers extending
throughout the cytoplasm
It organizes the cell’s structures and activities,
anchoring many organelles
© 2014 Pearson Education, Inc.
Video: Organelle Movement
Video: Organelle Transport
Video: Microtubule Transport
- 104. Roles of the Cytoskeleton: Support and Motility
The cytoskeleton helps to support the cell and
maintain its shape
It interacts with motor proteins to produce motility
Inside the cell, vesicles and other organelles can
“walk” along the tracks provided by the cytoskeleton
© 2014 Pearson Education, Inc.
- 105. © 2014 Pearson Education, Inc.
Figure 4.21
Microtubule Vesicles
(b) SEM of a squid giant axon
Receptor for
motor protein
0.25 µm
Vesicle
Motor protein
(ATP powered)
ATP
Microtubule
of cytoskeleton
(a) Motor proteins “walk” vesicles along cytoskeletal
fibers.
- 106. © 2014 Pearson Education, Inc.
Figure 4.21a
Microtubule Vesicles
(b) SEM of a squid giant axon
0.25 µm
- 107. Components of the Cytoskeleton
Three main types of fibers make up the cytoskeleton
Microtubules are the thickest of the three components
of the cytoskeleton
Microfilaments, also called actin filaments, are the
thinnest components
Intermediate filaments are fibers with diameters in a
middle range
© 2014 Pearson Education, Inc.
- 108. © 2014 Pearson Education, Inc.
Video: Actin in Crawling Cell
Video: Actin in Neuron
Video: Actin Cytoskeleton
Video: Cytoplasmic Stream
Video: Microtubule Movement
Video: Chloroplast Movement
Video: Microtubules
- 110. © 2014 Pearson Education, Inc.
Table 4.1a
Column of tubulin dimers
Microtubules
25 nm
Tubulin dimerβα
- 111. © 2014 Pearson Education, Inc.
Table 4.1b
Actin subunit
Microfilaments
7 nm
- 112. © 2014 Pearson Education, Inc.
Table 4.1c
Keratin
proteins
Fibrous subunit
(keratins coiled
together)
Intermediate filaments
8–12 nm
- 113. Microtubules
Microtubules are hollow rods constructed from
globular protein dimers called tubulin
Functions of microtubules
Shape and support the cell
Guide movement of organelles
Separate chromosomes during cell division
© 2014 Pearson Education, Inc.
- 114. Centrosomes and Centrioles
In animal cells, microtubules grow out from a
centrosome near the nucleus
The centrosome is a “microtubule-organizing center”
The centrosome has a pair of centrioles, each with
nine triplets of microtubules arranged in a ring
© 2014 Pearson Education, Inc.
- 115. © 2014 Pearson Education, Inc.
Animation: Cilia Flagella
Video: Ciliary Motion
Video: Chlamydomonas
Video: Flagellum Microtubule
Video: Sperm Flagellum
Video: Flagella in Sperm
Video: Paramecium Cilia
- 116. © 2014 Pearson Education, Inc.
Figure 4.22
Microtubule
Centrioles
Centrosome
- 117. Cilia and Flagella
Microtubules control the beating of cilia and
flagella, microtubule-containing extensions
projecting from some cells
Flagella are limited to one or a few per cell, while
cilia occur in large numbers on cell surfaces
Cilia and flagella also differ in their beating patterns
© 2014 Pearson Education, Inc.
- 118. Cilia and flagella share a common structure
A core of microtubules sheathed by the plasma
membrane
A basal body that anchors the cilium or flagellum
A motor protein called dynein, which drives the
bending movements of a cilium or flagellum
© 2014 Pearson Education, Inc.
- 119. © 2014 Pearson Education, Inc.
Figure 4.23
Plasma
membrane
Microtubules
Basal body
(a) Longitudinal section
of motile cilium
(c) Cross section of basal body
(b) Cross section of
motile cilium
Triplet
Plasma
membrane
Cross-linking
proteins
between outer
doublets
Radial spoke
Central
microtubule
Outer microtubule
doublet
Dynein proteins
0.1 µm
0.5 µm
0.1 µm
- 120. © 2014 Pearson Education, Inc.
Figure 4.23a
Plasma
membrane
Microtubules
Basal body
(a) Longitudinal section of
motile cilium
0.5 µm
- 121. © 2014 Pearson Education, Inc.
Figure 4.23b
(b) Cross section of
motile cilium
Plasma
membrane
Cross-linking
proteins
between outer
doublets
Radial spoke
Central
microtubule
Outer microtubule
doublet
Dynein proteins
0.1 µm
- 122. © 2014 Pearson Education, Inc.
Figure 4.23ba
(b) Cross section of
motile cilium
Cross-linking
proteins
between outer
doublets
Radial spoke
Central
microtubule
Dynein proteins
0.1 µm Outer microtubule
doublet
- 123. © 2014 Pearson Education, Inc.
Figure 4.23c
(c) Cross section of basal body
Triplet
0.1 µm
- 124. © 2014 Pearson Education, Inc.
Figure 4.23ca
(c) Cross section of basal body
Triplet
0.1 µm
- 125. How dynein “walking” moves flagella and cilia
Dynein arms alternately grab, move, and release the
outer microtubules
The outer doublets and central microtubules are held
together by flexible cross-linking proteins
Movements of the doublet arms cause the cilium or
flagellum to bend
© 2014 Pearson Education, Inc.
- 126. Microfilaments (Actin Filaments)
Microfilaments are thin solid rods, built from
molecules of globular actin subunits
The structural role of microfilaments is to bear
tension, resisting pulling forces within the cell
Bundles of microfilaments make up the core of
microvilli of intestinal cells
© 2014 Pearson Education, Inc.
- 127. © 2014 Pearson Education, Inc.
Figure 4.24
Microfilaments
(actin filaments)
0.25 µm Microvillus
Plasma
membrane
- 128. Microfilaments that function in cellular motility
interact with the motor protein myosin
For example, actin and myosin interact to cause
muscle contraction, amoeboid movement of white
blood cells, and cytoplasmic streaming in plant cells
© 2014 Pearson Education, Inc.
- 129. Intermediate Filaments
Intermediate filaments are larger than
microfilaments but smaller than microtubules
They support cell shape and fix organelles in place
Intermediate filaments are more permanent
cytoskeleton elements than the other two classes
© 2014 Pearson Education, Inc.
- 130. Concept 4.7: Extracellular components and
connections between cells help coordinate
cellular activities
Most cells synthesize and secrete materials that
are external to the plasma membrane
These extracellular materials are involved in many
cellular functions
© 2014 Pearson Education, Inc.
- 131. Cell Walls of Plants
The cell wall is an extracellular structure that
distinguishes plant cells from animal cells
Prokaryotes, fungi, and some protists also have
cell walls
The cell wall protects the plant cell, maintains its
shape, and prevents excessive uptake of water
Plant cell walls are made of cellulose fibers
embedded in other polysaccharides and protein
© 2014 Pearson Education, Inc.
- 132. Plant cell walls may have multiple layers
Primary cell wall: relatively thin and flexible
Middle lamella: thin layer between primary walls of
adjacent cells
Secondary cell wall (in some cells): added between
the plasma membrane and the primary cell wall
Plasmodesmata are channels between adjacent
plant cells
© 2014 Pearson Education, Inc.
Video: Extracellular Matrix
Video: Fibronectin
Video: Collagen Model
- 133. © 2014 Pearson Education, Inc.
Figure 4.25
Secondary
cell wall
Central vacuole
Primary
cell wall
1 µm
Middle
lamella
Plasmodesmata
Cytosol
Plasma membrane
Plant cell walls
- 134. © 2014 Pearson Education, Inc.
Figure 4.25a
Secondary
cell wall
Primary
cell wall
1 µm
Middle
lamella
- 135. The Extracellular Matrix (ECM) of Animal Cells
Animal cells lack cell walls but are covered by an
elaborate extracellular matrix (ECM)
The ECM is made up of glycoproteins such as
collagen, proteoglycans, and fibronectin
ECM proteins bind to receptor proteins in the
plasma membrane called integrins
© 2014 Pearson Education, Inc.
- 139. Cell Junctions
Neighboring cells in an animal or plant often
adhere, interact, and communicate through direct
physical contact
There are several types of intercellular junctions
that facilitate this
Plasmodesmata
Tight junctions
Desmosomes
Gap junctions
© 2014 Pearson Education, Inc.
- 140. Plasmodesmata in Plant Cells
Plasmodesmata are channels that perforate plant
cell walls
Through plasmodesmata, water and small solutes
(and sometimes proteins and RNA) can pass from
cell to cell
© 2014 Pearson Education, Inc.
- 141. Tight Junctions, Desmosomes, and Gap Junctions
in Animal Cells
Animal cells have three main types of cell junctions
Tight junctions
Desmosomes
Gap junctions
All are especially common in epithelial tissue
© 2014 Pearson Education, Inc.
Animation: Gap Junctions
Animation: Tight Junctions
Animation: Desmosomes
- 142. © 2014 Pearson Education, Inc.
Figure 4.27
1 µm
Intermediate
filaments
TEM
0.5 µm
TEM
0.1 µm
TEM
Tight
junction
Tight
junction
Ions or small
molecules
Extracellular
matrix
Gap
junction
Desmosome
Space
between cells
Plasma membranes
of adjacent cells
Tight junctions prevent
fluid from moving
across a layer of cells
- 143. © 2014 Pearson Education, Inc.
Figure 4.27a
Intermediate
filaments
Tight
junction
Ions or small
molecules
Extracellular
matrix
Gap
junction
Desmosome
Space
between cells
Plasma
membranes of
adjacent cells
Tight junctions
prevent fluid from
moving across a
layer of cells
- 144. © 2014 Pearson Education, Inc.
Figure 4.27b
0.5 µm
TEM
Tight
junction
- 146. © 2014 Pearson Education, Inc.
Figure 4.27d
0.1 µm
Gap junctions
(TEM)
- 147. The Cell: A Living Unit Greater Than the Sum of
Its Parts
Cellular functions arise from cellular order
For example, a macrophage’s ability to destroy
bacteria involves the whole cell, coordinating
components such as the cytoskeleton, lysosomes,
and plasma membrane
© 2014 Pearson Education, Inc.
- 149. © 2014 Pearson Education, Inc.
Figure 4.UN01a
1 µm
Mature parent
cell
Budding
cell
Notas do Editor
- Figure 4.1 How do your brain cells help you learn about biology?
- Figure 4.2 The size range of cells and how we view them
- Figure 4.2a The size range of cells and how we view them (part 1: LM to unaided eye)
- Figure 4.2b The size range of cells and how we view them (part 2: EM to LM)
- Figure 4.3 Exploring microscopy
- Figure 4.3a Exploring microscopy (part 1: light microscopy)
- Figure 4.3aa Exploring microscopy (part 1a: brightfield, unstained)
- Figure 4.3ab Exploring microscopy (part 1b: brightfield, stained)
- Figure 4.3ac Exploring microscopy (part 1c: phase-contrast)
- Figure 4.3ad Exploring microscopy (part 1d: differential-interference contrast)
- Figure 4.3b Exploring microscopy (part 2: light microscopy)
- Figure 4.3ba Exploring microscopy (part 2a: fluorescence)
- Figure 4.3bb Exploring microscopy (part 2b: confocal, blurry)
- Figure 4.3bc Exploring microscopy (part 2c: confocal, sharp)
- Figure 4.3c Exploring microscopy (part 3: electron microscopy)
- Figure 4.3ca Exploring microscopy (part 3a: SEM)
- Figure 4.3cb Exploring microscopy (part 3b: TEM)
- Figure 4.4 A prokaryotic cell
- Figure 4.4a A prokaryotic cell (TEM)
- Figure 4.5 The plasma membrane
- Figure 4.5a The plasma membrane (TEM)
- Figure 4.5b The plasma membrane
- Figure 4.6 Geometric relationships between surface area and volume
- Figure 4.7a Exploring eukaryotic cells (part 1: animal cell cutaway)
- Figure 4.7b Exploring eukaryotic cells (part 2: plant cell cutaway)
- Figure 4.7c Exploring eukaryotic cells (part 3: animal cell, TEM)
- Figure 4.7d Exploring eukaryotic cells (part 4: fungal cell, SEM)
- Figure 4.7e Exploring eukaryotic cells (part 5: fungal cell, TEM)
- Figure 4.7f Exploring eukaryotic cells (part 6: plant cell, TEM)
- Figure 4.7g Exploring eukaryotic cells (part 7: protist cell, SEM)
- Figure 4.7h Exploring eukaryotic cells (part 8: protist cell, TEM)
- Figure 4.8 The nucleus and its envelope
- Figure 4.8a The nucleus and its envelope (part 1: detail of art)
- Figure 4.8b The nucleus and its envelope (part 2: nuclear envelope, TEM)
- Figure 4.8c The nucleus and its envelope (part 3: pore complexes, TEM)
- Figure 4.8d The nucleus and its envelope (part 4: nuclear lamina, TEM)
- Figure 4.9 Ribosomes
- Figure 4.9a Ribosomes (TEM)
- Figure 4.10 Endoplasmic reticulum (ER)
- Figure 4.10a Endoplasmic reticulum (ER) (part 1: detail of art)
- Figure 4.10b Endoplasmic reticulum (ER) (part 2: TEM)
- Figure 4.11 The Golgi apparatus
- Figure 4.11a The Golgi apparatus (part 1: detail of art)
- Figure 4.11b The Golgi apparatus (part 2: TEM)
- Figure 4.12 Lysosomes: phagocytosis
- Figure 4.12a Lysosomes: phagocytosis (part 1: detail of art)
- Figure 4.12b Lysosomes: phagocytosis (part 2: TEM)
- Figure 4.13 Lysosomes: autophagy
- Figure 4.13a Lysosomes: autophagy (part 1: detail of art)
- Figure 4.13b Lysosomes: autophagy (part 2: TEM)
- Figure 4.14 The plant cell vacuole
- Figure 4.14a The plant cell vacuole (TEM)
- Figure 4.15-1 Review: relationships among organelles of the endomembrane system (step 1)
- Figure 4.15-2 Review: relationships among organelles of the endomembrane system (step 2)
- Figure 4.15-3 Review: relationships among organelles of the endomembrane system (step 3)
- Figure 4.16 The endosymbiont theory of the origin of mitochondria and chloroplasts in eukaryotic cells
- Figure 4.17 The mitochondrion, site of cellular respiration
- Figure 4.17a The mitochondrion, site of cellular respiration (TEM)
- Figure 4.18 The chloroplast, site of photosynthesis
- Figure 4.18a The chloroplast, site of photosynthesis (part 1: detail)
- Figure 4.18aa The chloroplast, site of photosynthesis (part 1a: TEM)
- Figure 4.18b The chloroplast, site of photosynthesis (part 2: fluorescence micrograph)
- Figure 4.19 A peroxisome
- Figure 4.20 The cytoskeleton
- Figure 4.21 Motor proteins and the cytoskeleton
- Figure 4.21a Motor proteins and the cytoskeleton (SEM)
- Table 4.1 The structure and function of the cytoskeleton
- Table 4.1a The structure and function of the cytoskeleton (part 1: microtubules)
- Table 4.1b The structure and function of the cytoskeleton (part 2: microfilaments)
- Table 4.1c The structure and function of the cytoskeleton (part 3: intermediate filaments)
- Figure 4.22 Centrosome containing a pair of centrioles
- Figure 4.23 Structure of a flagellum or motile cilium
- Figure 4.23a Structure of a flagellum or motile cilium (part 1: longitudinal section of cilium, TEM)
- Figure 4.23b Structure of a flagellum or motile cilium (part 2: cilium cross section)
- Figure 4.23ba Structure of a flagellum or motile cilium (part 2a: cilium cross section, TEM)
- Figure 4.23c Structure of a flagellum or motile cilium (part 3: basal body cross section)
- Figure 4.23ca Structure of a flagellum or motile cilium (part 3a: basal body cross section, TEM)
- Figure 4.24 A structural role of microfilaments
- Figure 4.25 Plant cell walls
- Figure 4.25a Plant cell walls (TEM)
- Figure 4.26 Extracellular matrix (ECM) of an animal cell
- Figure 4.26a Extracellular matrix (ECM) of an animal cell (part 1: detail of art)
- Figure 4.26b Extracellular matrix (ECM) of an animal cell (part 2: proteoglycan complex)
- Figure 4.27 Exploring cell junctions in animal tissues
- Figure 4.27a Exploring cell junctions in animal tissues (part 1: detail of art)
- Figure 4.27b Exploring cell junctions in animal tissues (part 2: tight junction, TEM)
- Figure 4.27c Exploring cell junctions in animal tissues (part 3: desmosome, TEM)
- Figure 4.27d Exploring cell junctions in animal tissues (part 4: gap junctions, TEM)
- Figure 4.28 The emergence of cellular functions
- Figure 4.UN01a Skills exercise: using a scale bar to calculate volume and surface area of a cell (part 1)
- Figure 4.UN01b Skills exercise: using a scale bar to calculate volume and surface area of a cell (part 2)
- Figure 4.UN02 Summary of key concepts: nucleus and ribosomes
- Figure 4.UN03 Summary of key concepts: endomembrane system
- Figure 4.UN04 Summary of key concepts: mitochondria and chloroplasts