CAMPBELL BIOLOGY: CONCEPTS & CONNECTIONS,
NINTH EDITION, GLOBAL EDITION
PowerPoint Lectures
Chapter 4
A Tour of the Cell
TAYLOR
SIMON
DICKEY
HOGAN
REECE
© 2018 Pearson Education Ltd.
Lecture by Edward J. Zalisko
4.1 Microscopes reveal the world of the cell
• In the 1800s, early studies of cells led to cell theory,
which states that
• all living things are composed of cells and
• all cells come from other cells.
• The light microscope can display living cells.
• The greater magnification and resolution of scanning
and transmission electron microscopes reveal the
ultrastructure of cells.
• 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.
Figure 4.1e
10 m
Human height
1m
Length of some
(1,000 mm)
nerve and
Unaided eye
0.1 m muscle cells
(100 mm) Chicken egg
0.01 m
(10 mm)
Frog egg
1 mm
(1,000 µm)
Light microscope
Paramecium
100 µm Human egg
Most plant and
animal cells
Electron microscope
10 µm
Nucleus
Most bacteria
1 µm Mitochondrion
(1,000 nm)
100 nm Smallest bacteria
Viruses
Ribosome
10 nm
Proteins
Lipids
1 nm
Small molecules
− −
0.1 nm Atoms +
© 2018 Pearson Education Ltd.
4.2 The small size of cells relates to the need
to exchange materials across the plasma
membrane
• The microscopic size of most cells provides a large
surface-to-volume ratio.
• The plasma membrane is a phospholipid bilayer
with embedded proteins.
• 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.
3 1
1
3
Total volume 27 units3 27 units3
Total surface
area 54 units2 162 units2
Surface-to- 2 6
volume ratio
A small cell has a greater surface area relative to
volume than a large cell, compare the surface-to-
volume ratios of the large cube and one of the
small cubes in Figure 4.2A.
Figure 4.2b
The structure of cell membrane
Outside cell Hydrophilic
heads
Hydrophobic
tails
Phospholipid
Inside cell
Channel Hydrophilic Hydrophobic
protein regions of regions of
a protein a protein
© 2018 Pearson Education Ltd.
4.3 Prokaryotic cells are structurally simpler
than eukaryotic cells
• All cells have a plasma membrane, DNA, ribosomes,
and cytosol.
• Bacteria and archaea are prokaryotic cells.
• All other forms of life have 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.
© 2018 Pearson Education Ltd.
Figure 4.3
Helicobactor pylori,
Fimbriae a bacterium that
causes stomach ulcers
Ribosomes
Nucleoid
Plasma
membrane
Cell wall
Bacterial
chromosome
Capsule
A typical rod-shaped
bacterium Flagella Colorized TEM
20,940×
×
© 2018 Pearson Education Ltd.
4.4 Eukaryotic cells are partitioned into
functional compartments
• Membrane-enclosed organelles compartmentalize a
cell’s activities.
• The organelles and other structures of eukaryotic
cells can be organized into four basic functional
groups:
1. The nucleus and ribosomes carry out the genetic
control of the cell.
2. Organelles involved in the manufacture,
distribution, and breakdown of molecules include
the endoplasmic reticulum, Golgi apparatus,
lysosomes, vacuoles, and peroxisomes.
© 2018 Pearson Education Ltd.
4.4 Eukaryotic cells are partitioned into
functional compartments
3. Mitochondria in all cells and chloroplasts in plant
cells function in energy processing.
4. Structural support, movement, and communication
between cells are the functions of the cytoskeleton,
plasma membrane, and plant cell wall.
Figure 4.4a
NUCLEUS
Nuclear envelope
Nucleolus
Rough
endoplasmic Chromatin
CYTOSKELETON
reticulum Microtubule
Microfilament
Intermediate
filament
Ribosomes
Peroxisome
Smooth
endoplasmic
reticulum Plasma
membrane
Golgi apparatus Centrosome
with pair of
Lysosome
centrioles
Mitochondrion
© 2018 Pearson Education Ltd.
4.5 The nucleus contains the cell’s genetic
instructions
• The nucleus houses the cell’s DNA, which directs
protein synthesis via messenger RNA (mRNA).
• Subunits of ribosomes are assembled in the
nucleolus.
4.6 Ribosomes make proteins for use in the
cell and export
• Ribosomes
• are composed of ribosomal RNA and proteins and
• synthesize proteins according to directions from DNA.
• Cells that make a lot of proteins have a large number
of ribosomes.
Figure 4.6
Endoplasmic
reticulum
Bound ribosome
Endoplasmic
reticulum
Protein
Ribosome
Free ribosome
mRNA
© 2018 Pearson Education Ltd.
4.7 Many organelles are connected in the
endomembrane system
• Many of the membranes within a eukaryotic cell are
part of the endomembrane system.
• Many of these organelles interact in the
• synthesis, distribution, storage, and export of
molecules.
4.8 The endoplasmic reticulum is a biosynthetic
workshop
• The ER is a membranous network of tubes and sacs.
• Smooth ER synthesizes lipids and processes toxins.
• Rough ER bound ribosomes on its surface membrane
make and secretory proteins.
Figure 4.8b
Molecules transported by vesicle
Transport vesicle
buds off 4
mRNA
Secretory
Bound ribosome protein
inside trans-
port vesicle
1 Sugar
chain
Glycoprotein
2
Growing
polypeptide Rough ER
© 2018 Pearson Education Ltd.
4.9 The Golgi apparatus modifies, sorts, and
ships cell products
• The Golgi apparatus consists of stacks of sacs in
which products of the ER are processed and then
sent to other organelles or to the cell surface.
4.10 Lysosomes are digestive compartments
within a cell
• Lysosomes house enzymes that break down
ingested substances and damaged organelles.
• Peroxisomes are metabolic compartments that do
not originate from the endomembrane system.
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.
• Plant cells contain a large central vacuole that stores
molecules and wastes and facilitates growth.
Lysosome
Digestion
Digestive
enzymes
Food vacuole
Plasma membrane
© 2018 Pearson Education Ltd.
4.13 Mitochondria harvest chemical energy
from food
• Mitochondria are organelles that carry out cellular
respiration in nearly all eukaryotic cells.
• 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.
• The endosymbiont theory states that mitochondria and
chloroplasts were formerly small prokaryotes that
began living within larger cells.
4.16 The cell’s internal skeleton helps organize
its structure and activities
• The cytoskeleton includes microfilaments,
intermediate filaments, and microtubules. Their
functions include
• maintenance of cell shape,
• anchorage and movement of organelles,
• amoeboid movement, and
• muscle contraction.
Intermediate filament Microfilament
Microtubule
4.18 Cilia and flagella move when
microtubules bend
• Eukaryotic cilia and flagella are locomotor appendages
made of microtubules in a “9 + 2” arrangement.
• Flagella, longer than cilia, propel 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.
Cilia
Flagellum
4.19 The extracellular matrix of animal cells
functions in support and regulation
• Animal cells
synthesize and
secrete an elaborate
extracellular matrix
(ECM), which
• binds tissue cells
together,
• supports the
plasma membrane,
and
• communicates with
the cytoskeleton.
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 bind cells to form leak proof
sheets.
• Anchoring junctions rivet cells into strong tissues.
• Gap junctions allow ions and small molecules to
flow from cell to cell.
• Plant cells have cell junctions called
plasmodesmata that allow plant tissues to share
water, nourishment, and chemical messages
Figure 4.20
Tight junctions
prevent fluid from
moving across a
layer of cells
Tight junction
Anchoring
junction
Gap junction
Plasma membranes
of adjacent cells
Ions or small molecules Extracellular matrix
© 2018 Pearson Education Ltd.
Organelles and Cystic Fibrosis (肺纖維性囊腫)
Figure 4.21
Plant cell
walls
Vacuole
Plasmodesmata
Pectin layer between cells
Primary cell wall
Secondary cell wall
Plasma membrane
Cytosol
© 2018 Pearson Education Ltd.
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.
生命的學習
我本害怕孤單
我本害怕孤單,
孤單,
直到我學會愛自己.
直到我學會愛自己.
我本害怕失敗
我本害怕失敗,
失敗,
直到我體會不嘗試,
直到我體會不嘗試,
則只有失敗一途.
則只有失敗一途.
