biology in focus chapter 4
TRANSCRIPT
![Page 1: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/1.jpg)
CAMPBELL BIOLOGY IN FOCUS
© 2014 Pearson Education, Inc.
Urry • Cain • Wasserman • Minorsky • Jackson • Reece
Lecture Presentations by Kathleen Fitzpatrick and Nicole Tunbridge
4A Tour of the Cell
![Page 2: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/2.jpg)
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.
![Page 3: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/3.jpg)
© 2014 Pearson Education, Inc.
Figure 4.1
![Page 4: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/4.jpg)
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.
![Page 5: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/5.jpg)
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.
![Page 6: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/6.jpg)
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.
![Page 7: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/7.jpg)
© 2014 Pearson Education, Inc.
Figure 4.2
Most plant andanimal cells
Length of somenerve andmuscle cells
VirusesSmallest bacteria
Human height
Chicken egg
Frog egg
Human egg
NucleusMost bacteriaMitochondrion
Super-resolution
microscopy
Atoms
Small molecules
Ribosomes
ProteinsLipids
Un
aid
ed e
ye
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
![Page 8: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/8.jpg)
© 2014 Pearson Education, Inc.
Figure 4.2a
Length of somenerve andmuscle cells
Human height
Chicken egg
Frog egg
Human eggU
nai
ded
eye
LM
10 m
1 m
0.1 m
1 cm
1 mm
100 µm
![Page 9: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/9.jpg)
© 2014 Pearson Education, Inc.
Figure 4.2b
Most plant andanimal cells
VirusesSmallest bacteria
NucleusMost bacteriaMitochondrion
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
![Page 10: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/10.jpg)
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.
![Page 11: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/11.jpg)
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.
![Page 12: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/12.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3
Scanning electronmicroscopy (SEM)
Transmission electronmicroscopy (TEM)
Longitudinal sectionof cilium
Cross sectionof cilium
Cilia
2 µm
2 µm
50
µm
10
µm
50 µ
m
Brightfield(unstained specimen)
Electron Microscopy (EM)
Fluorescence
Brightfield(stained specimen)
Differential-interferencecontrast (Nomarski)
Phase-contrast
Confocal
Light Microscopy (LM)
![Page 13: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/13.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3a
50 µ
m
Brightfield(unstained specimen)
Brightfield(stained specimen)
Differential-interferencecontrast (Nomarski)
Phase-contrast
Light Microscopy (LM)
![Page 14: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/14.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3aa
50
µm
Brightfield(unstained specimen)
![Page 15: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/15.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3ab
Brightfield(stained specimen)
50
µm
![Page 16: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/16.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3ac
Phase-contrast
50 µ
m
![Page 17: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/17.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3ad
Differential-interferencecontrast (Nomarski)
50
µm
![Page 18: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/18.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3b
50 µ
m
10 µ
m
Fluorescence Confocal
Light Microscopy (LM)
![Page 19: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/19.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3ba
10
µm
Fluorescence
![Page 20: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/20.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3bb
Confocal: without technique
50 µ
m
![Page 21: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/21.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3bc
Confocal: with technique
50 µ
m
![Page 22: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/22.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3c
Scanning electronmicroscopy (SEM)
Transmission electronmicroscopy (TEM)
Longitudinal sectionof cilium
Cross sectionof cilium
Cilia
2 µm
Electron Microscopy (EM)
![Page 23: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/23.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3ca
Scanning electronmicroscopy (SEM)
Cilia
2 µm
![Page 24: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/24.jpg)
© 2014 Pearson Education, Inc.
Figure 4.3cb
Transmission electronmicroscopy (TEM)
Longitudinal sectionof cilium
Cross sectionof cilium
2 µm
![Page 25: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/25.jpg)
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.
![Page 26: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/26.jpg)
Cell Fractionation
Cell fractionation breaks up cells and separates the components, using centrifugation
Cell components separate based on theirrelative size
Cell fractionation enables scientists to determine the functions of organelles
Biochemistry and cytology help correlate cell function with structure
© 2014 Pearson Education, Inc.
![Page 27: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/27.jpg)
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.
![Page 28: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/28.jpg)
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.
![Page 29: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/29.jpg)
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.
![Page 30: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/30.jpg)
© 2014 Pearson Education, Inc.
Figure 4.4
(a) A typical rod-shapedbacterium
0.5 µm
(b) A thin section throughthe bacterium Bacilluscoagulans (TEM)
Bacterialchromosome
Fimbriae
Nucleoid
Ribosomes
Cell wall
Plasma membrane
Capsule
Flagella
![Page 31: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/31.jpg)
© 2014 Pearson Education, Inc.
Figure 4.4a
0.5 µm
(b) A thin section throughthe bacterium Bacilluscoagulans (TEM)
Nucleoid
Ribosomes
Cell wall
Plasma membrane
Capsule
![Page 32: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/32.jpg)
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.
![Page 33: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/33.jpg)
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.
![Page 34: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/34.jpg)
© 2014 Pearson Education, Inc.
Figure 4.5
0.1 µm
(a) TEM of a plasmamembraneOutside of cell
(b) Structure of the plasma membrane
Insideof cell
Hydrophilicregion
Hydrophilicregion
Hydrophobicregion
Carbohydrate side chains
Phospholipid Proteins
![Page 35: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/35.jpg)
© 2014 Pearson Education, Inc.
Figure 4.5a
0.1 µm
(a) TEM of a plasmamembrane
Outside of cell
Insideof cell
![Page 36: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/36.jpg)
© 2014 Pearson Education, Inc.
Figure 4.5b
(b) Structure of the plasma membrane
Hydrophilicregion
Hydrophilicregion
Hydrophobicregion
Carbohydrate side chains
Phospholipid Proteins
![Page 37: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/37.jpg)
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.
![Page 38: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/38.jpg)
© 2014 Pearson Education, Inc.
Figure 4.6
750
Surface area increases whiletotal volume remains constant
125
150
125
6
1
6
1
61.2
51
Total surface area[sum of the surface areas(height × width) of all boxsides × number of boxes]
Total volume[height × width × length× number of boxes]
Surface-to-volumeratio[surface area ÷ volume]
![Page 39: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/39.jpg)
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
![Page 40: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/40.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7a
CYTOSKELETON:
NUCLEUS
ENDOPLASMIC RETICULUM (ER)
Smooth ER
Rough ERFlagellum
Centrosome
Microfilaments
Intermediatefilaments
Microvilli
Microtubules
Mitochondrion
Peroxisome Golgi apparatus
Lysosome
Plasmamembrane
Ribosomes
Nucleolus
Nuclearenvelope
Chromatin
![Page 41: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/41.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7b
CYTO-SKELETON
NUCLEUS
Smooth endoplasmicreticulum
Chloroplast
Central vacuole
MicrofilamentsIntermediatefilaments
Cell wall
Microtubules
Mitochondrion
Peroxisome
Golgiapparatus
Plasmodesmata
Plasma membrane
Ribosomes
NucleolusNuclear envelope
Chromatin
Wall of adjacent cell
Rough endoplasmicreticulum
![Page 42: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/42.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7c
Nucleolus
Nucleus
Cell
10 µ
m
Human cells from lining of uterus(colorized TEM)
![Page 43: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/43.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7d
5 µ
m
Parentcell
Buds
Yeast cells budding (colorized SEM)
![Page 44: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/44.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7e
1 µm
A single yeast cell (colorized TEM)
Mitochondrion
Nucleus
Vacuole
Cell wall
![Page 45: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/45.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7f
5 µ
m Cell wall
Cell
Chloroplast
Mitochondrion
Nucleus
Nucleolus
Cells from duckweed (colorized TEM)
![Page 46: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/46.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7g
8 µ
m
Chlamydomonas(colorized SEM)
![Page 47: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/47.jpg)
© 2014 Pearson Education, Inc.
Figure 4.7h
1 µ
m
Chlamydomonas (colorized TEM)
Cell wall
Flagella
Chloroplast
Vacuole
Nucleus
Nucleolus
![Page 48: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/48.jpg)
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.
![Page 49: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/49.jpg)
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.
![Page 50: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/50.jpg)
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.
![Page 51: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/51.jpg)
© 2014 Pearson Education, Inc.
Figure 4.8
Ribosome
1 µm
Chromatin
Rough ER
Nucleus
Nucleolus
Nucleus
Chromatin
0.5
µm
0.25
µm
Nuclear envelope:
Nuclear pore
Inner membraneOuter membrane
Porecomplex
Close-upof nuclearenvelope
Nuclear lamina (TEM)
Surface of nuclearenvelope
Pore complexes (TEM)
![Page 52: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/52.jpg)
© 2014 Pearson Education, Inc.
Figure 4.8a
Ribosome
Chromatin
Rough ER
Nucleus
Nucleolus
Chromatin
Nuclear envelope:
Nuclear pore
Inner membraneOuter membrane
Porecomplex
Close-upof nuclearenvelope
![Page 53: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/53.jpg)
© 2014 Pearson Education, Inc.
Figure 4.8b
1 µm
Nuclear envelope:
Nuclear pore
Inner membraneOuter membrane
Surface of nuclear envelope
![Page 54: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/54.jpg)
© 2014 Pearson Education, Inc.
Figure 4.8c
0.25
µm
Pore complexes (TEM)
![Page 55: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/55.jpg)
© 2014 Pearson Education, Inc.
Figure 4.8d
0.5
µm
Nuclear lamina (TEM)
![Page 56: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/56.jpg)
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.
![Page 57: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/57.jpg)
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.
![Page 58: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/58.jpg)
© 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)
RibosomesER
0.25 µm
Largesubunit
Smallsubunit
![Page 59: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/59.jpg)
© 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
![Page 60: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/60.jpg)
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.
![Page 61: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/61.jpg)
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
![Page 62: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/62.jpg)
© 2014 Pearson Education, Inc.
Figure 4.10
Transport vesicle
Smooth ER
RoughER
Ribosomes TransitionalER
CisternaeER lumen
Smooth ER Rough ER
Nuclearenvelope
0.2 µm
![Page 63: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/63.jpg)
© 2014 Pearson Education, Inc.
Figure 4.10a
Transport vesicle
Smooth ER
RoughER
Ribosomes TransitionalER
CisternaeER lumen
Nuclearenvelope
![Page 64: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/64.jpg)
© 2014 Pearson Education, Inc.
Figure 4.10b
Smooth ER Rough ER0.2 µm
![Page 65: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/65.jpg)
Functions of Smooth ER
The smooth ER
Synthesizes lipids
Metabolizes carbohydrates
Detoxifies drugs and poisons
Stores calcium ions
© 2014 Pearson Education, Inc.
![Page 66: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/66.jpg)
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.
![Page 67: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/67.jpg)
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
![Page 68: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/68.jpg)
© 2014 Pearson Education, Inc.
Figure 4.11
TEM of Golgi apparatus
Golgiapparatus
trans face(“shipping”side of Golgiapparatus)
Cisternae
0.1 µmcis face(“receiving” side of Golgi apparatus)
![Page 69: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/69.jpg)
© 2014 Pearson Education, Inc.
Figure 4.11a
trans face(“shipping”side of Golgiapparatus)
Cisternae
cis face(“receiving” side of Golgi apparatus)
![Page 70: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/70.jpg)
© 2014 Pearson Education, Inc.
Figure 4.11b
TEM of Golgi apparatus
0.1 µm
![Page 71: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/71.jpg)
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.
![Page 72: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/72.jpg)
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
![Page 73: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/73.jpg)
© 2014 Pearson Education, Inc.
Figure 4.12
Lysosome
1 µmNucleus
Lysosome
Digestiveenzymes
Plasmamembrane
Food vacuole
Lysosomes: Phagocytosis
Digestion
![Page 74: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/74.jpg)
© 2014 Pearson Education, Inc.
Figure 4.12a
Lysosome
Digestiveenzymes
Plasmamembrane
Food vacuole
Lysosomes: Phagocytosis
Digestion
![Page 75: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/75.jpg)
© 2014 Pearson Education, Inc.
Figure 4.12b
Lysosome
1 µmNucleus
![Page 76: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/76.jpg)
© 2014 Pearson Education, Inc.
Figure 4.13
Lysosome
Lysosomes: Autophagy
Peroxisome
MitochondrionVesicle
Digestion
Mitochondrionfragment
Peroxisomefragment
Vesicle containing twodamaged organelles
1 µm
![Page 77: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/77.jpg)
© 2014 Pearson Education, Inc.
Figure 4.13a
Lysosome
Lysosomes: Autophagy
Peroxisome
MitochondrionVesicle
Digestion
![Page 78: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/78.jpg)
© 2014 Pearson Education, Inc.
Figure 4.13b
Mitochondrionfragment
Peroxisomefragment
Vesicle containing twodamaged organelles
1 µm
![Page 79: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/79.jpg)
Vacuoles: Diverse Maintenance Compartments
Vacuoles are large vesicles derived from the endoplasmic reticulum and Golgi apparatus
© 2014 Pearson Education, Inc.
![Page 80: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/80.jpg)
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.
![Page 81: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/81.jpg)
© 2014 Pearson Education, Inc.
Figure 4.14
Central vacuole
Centralvacuole
Chloroplast
Cytosol
Cell wall
Nucleus
Plant cell vacuole 5 µm
![Page 82: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/82.jpg)
© 2014 Pearson Education, Inc.
Figure 4.14a
Centralvacuole
Chloroplast
Cytosol
Cell wall
Nucleus
Plant cell vacuole 5 µm
![Page 83: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/83.jpg)
The Endomembrane System: A Review
The endomembrane system is a complex and dynamic player in the cell’s compartmental organization
© 2014 Pearson Education, Inc.
![Page 84: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/84.jpg)
© 2014 Pearson Education, Inc.
Figure 4.15-1
Rough ER
Nucleus
Smooth ER
Plasmamembrane
![Page 85: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/85.jpg)
© 2014 Pearson Education, Inc.
Figure 4.15-2
Plasmamembrane
Rough ER
cis Golgi
Nucleus
Smooth ER
trans Golgi
![Page 86: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/86.jpg)
© 2014 Pearson Education, Inc.
Figure 4.15-3
Plasmamembrane
Rough ER
cis Golgi
Nucleus
Smooth ER
trans Golgi
![Page 87: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/87.jpg)
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.
![Page 88: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/88.jpg)
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.
![Page 89: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/89.jpg)
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
![Page 90: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/90.jpg)
© 2014 Pearson Education, Inc.
Figure 4.16
Mitochondrion
Mitochondrion
Nonphotosyntheticeukaryote
Photosynthetic eukaryote
At leastone cell Chloroplast
Engulfing ofphotosyntheticprokaryote
Nucleus
Nuclearenvelope
Endoplasmicreticulum
Ancestor ofeukaryotic cells(host cell)
Engulfing of oxygen-using nonphotosyntheticprokaryote, whichbecomes a mitochondrion
![Page 91: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/91.jpg)
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.
![Page 92: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/92.jpg)
© 2014 Pearson Education, Inc.
Figure 4.17
Freeribosomesin themitochondrialmatrix
Mitochondrion
Intermembrane space
Matrix
Cristae
DNA
Outer membrane
Inner membrane
0.1 µm
![Page 93: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/93.jpg)
© 2014 Pearson Education, Inc.
Figure 4.17a
Matrix
Cristae
Outer membrane
Inner membrane
0.1 µm
![Page 94: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/94.jpg)
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.
![Page 95: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/95.jpg)
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.
![Page 96: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/96.jpg)
© 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)
![Page 97: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/97.jpg)
© 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
![Page 98: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/98.jpg)
© 2014 Pearson Education, Inc.
Figure 4.18aa
Inner and outer membranes
1 µm
Stroma
Granum
![Page 99: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/99.jpg)
© 2014 Pearson Education, Inc.
Figure 4.18b
50 µm
(b) Chloroplasts in an algal cell
Chloroplasts(red)
![Page 100: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/100.jpg)
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
![Page 101: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/101.jpg)
© 2014 Pearson Education, Inc.
Figure 4.19
Chloroplast
1 µm
Peroxisome
Mitochondrion
![Page 102: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/102.jpg)
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
![Page 103: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/103.jpg)
© 2014 Pearson Education, Inc.
Figure 4.20
10 µ
m
![Page 104: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/104.jpg)
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.
![Page 105: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/105.jpg)
© 2014 Pearson Education, Inc.
Figure 4.21
Microtubule Vesicles
(b) SEM of a squid giant axon
Receptor formotor protein
0.25 µm
Vesicle
Motor protein(ATP powered)
ATP
Microtubuleof cytoskeleton
(a) Motor proteins “walk” vesicles along cytoskeletalfibers.
![Page 106: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/106.jpg)
© 2014 Pearson Education, Inc.
Figure 4.21a
Microtubule Vesicles
(b) SEM of a squid giant axon
0.25 µm
![Page 107: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/107.jpg)
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.
![Page 108: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/108.jpg)
© 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
![Page 109: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/109.jpg)
© 2014 Pearson Education, Inc.
Table 4.1
![Page 110: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/110.jpg)
© 2014 Pearson Education, Inc.
Table 4.1a
Column of tubulin dimers
Microtubules
25 nm
Tubulin dimerβα
![Page 111: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/111.jpg)
© 2014 Pearson Education, Inc.
Table 4.1b
Actin subunit
Microfilaments
7 nm
![Page 112: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/112.jpg)
© 2014 Pearson Education, Inc.
Table 4.1c
Keratinproteins
Fibrous subunit(keratins coiledtogether)
Intermediate filaments
8–12 nm
![Page 113: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/113.jpg)
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.
![Page 114: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/114.jpg)
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.
![Page 115: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/115.jpg)
© 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
![Page 116: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/116.jpg)
© 2014 Pearson Education, Inc.
Figure 4.22
Microtubule
Centrioles
Centrosome
![Page 117: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/117.jpg)
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.
![Page 118: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/118.jpg)
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.
![Page 119: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/119.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23
Plasmamembrane
Microtubules
Basal body
(a) Longitudinal sectionof motile cilium
(c) Cross section of basal body
(b) Cross section of motile cilium
Triplet
Plasmamembrane
Cross-linkingproteinsbetween outerdoublets
Radial spoke
Centralmicrotubule
Outer microtubuledoublet
Dynein proteins
0.1 µm0.5 µm
0.1 µm
![Page 120: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/120.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23a
Plasmamembrane
Microtubules
Basal body
(a) Longitudinal section ofmotile cilium
0.5 µm
![Page 121: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/121.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23b
(b) Cross section of motile cilium
Plasmamembrane
Cross-linkingproteinsbetween outerdoublets
Radial spoke
Centralmicrotubule
Outer microtubuledoublet
Dynein proteins
0.1 µm
![Page 122: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/122.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23ba
(b) Cross section of motile cilium
Cross-linkingproteinsbetween outerdoublets
Radial spoke
Centralmicrotubule
Dynein proteins
0.1 µm Outer microtubuledoublet
![Page 123: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/123.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23c
(c) Cross section of basal body
Triplet
0.1 µm
![Page 124: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/124.jpg)
© 2014 Pearson Education, Inc.
Figure 4.23ca
(c) Cross section of basal body
Triplet
0.1 µm
![Page 125: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/125.jpg)
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.
![Page 126: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/126.jpg)
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.
![Page 127: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/127.jpg)
© 2014 Pearson Education, Inc.
Figure 4.24
Microfilaments(actin filaments)
0.25 µm Microvillus
Plasmamembrane
![Page 128: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/128.jpg)
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.
![Page 129: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/129.jpg)
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.
![Page 130: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/130.jpg)
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.
![Page 131: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/131.jpg)
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.
![Page 132: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/132.jpg)
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
![Page 133: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/133.jpg)
© 2014 Pearson Education, Inc.
Figure 4.25
Secondarycell wall
Central vacuole
Primarycell wall
1 µm
Middlelamella
Plasmodesmata
Cytosol
Plasma membrane
Plant cell walls
![Page 134: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/134.jpg)
© 2014 Pearson Education, Inc.
Figure 4.25a
Secondarycell wall
Primarycell wall
1 µm
Middlelamella
![Page 135: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/135.jpg)
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.
![Page 136: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/136.jpg)
© 2014 Pearson Education, Inc.
Figure 4.26
![Page 137: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/137.jpg)
© 2014 Pearson Education, Inc.
Figure 4.26a
![Page 138: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/138.jpg)
© 2014 Pearson Education, Inc.
Figure 4.26b
![Page 139: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/139.jpg)
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.
![Page 140: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/140.jpg)
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.
![Page 141: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/141.jpg)
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
![Page 142: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/142.jpg)
© 2014 Pearson Education, Inc.
Figure 4.27
1 µm
Intermediatefilaments
TEM
0.5 µmTEM
0.1 µmTE
M
Tightjunction
Tightjunction
Ions or smallmolecules
Extracellularmatrix
Gapjunction
Desmosome
Space between cells
Plasma membranesof adjacent cells
Tight junctions preventfluid from movingacross a layer of cells
![Page 143: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/143.jpg)
© 2014 Pearson Education, Inc.
Figure 4.27a
Intermediatefilaments
Tightjunction
Ions or smallmolecules
Extracellularmatrix
Gapjunction
Desmosome
Space between cells
Plasma membranes of adjacent cells
Tight junctions prevent fluid from moving across a layer of cells
![Page 144: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/144.jpg)
© 2014 Pearson Education, Inc.
Figure 4.27b
0.5 µmTEM
Tightjunction
![Page 145: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/145.jpg)
© 2014 Pearson Education, Inc.
Figure 4.27c
1 µm
Desmosome (TEM)
![Page 146: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/146.jpg)
© 2014 Pearson Education, Inc.
Figure 4.27d
0.1 µm
Gap junctions(TEM)
![Page 147: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/147.jpg)
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.
![Page 148: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/148.jpg)
© 2014 Pearson Education, Inc.
Figure 4.28
5 µ
m
![Page 149: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/149.jpg)
© 2014 Pearson Education, Inc.
Figure 4.UN01a
1 µm
Mature parentcell
Buddingcell
![Page 150: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/150.jpg)
© 2014 Pearson Education, Inc.
Figure 4.UN01b
rV = π r 3
34
d
![Page 151: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/151.jpg)
© 2014 Pearson Education, Inc.
Figure 4.UN02
![Page 152: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/152.jpg)
© 2014 Pearson Education, Inc.
Figure 4.UN03
![Page 153: Biology in Focus Chapter 4](https://reader034.vdocuments.mx/reader034/viewer/2022050613/587a4d001a28ab00148b6a9b/html5/thumbnails/153.jpg)
© 2014 Pearson Education, Inc.
Figure 4.UN04