KEY CONCEPTS
6.1 Biologists use microscopes and the tools of biochemistry to
study cells
6.2 Eukaryotic cells have internal membranes that
compartmentalize their functions
6.3 The eukaryotic cell’s genetic instructions are housed in the nucleus and carried out by the ribosomes
6.4 The endomembrane system regulates protein traffic and
performs metabolic functions in the cell
6.5 Mitochondria and chloroplasts change energy from one form to another
6.6 The cytoskeleton is a network of fibers that organizes structures and activities in the cell
6.7 Extracellular components and connections between cells help coordinate cellular activities
2. •All organisms are made of cells
•The cell is the simplest collection of matter
that can live
•Cell structure is correlated to cellular function
•All cells are related by their descent from
earlier cells
3. Microscopy
• Scientists use microscopes to visualize cells
too small to see with the naked eye
• In a light microscope (LM), visible light
passes through a specimen and then
through glass lenses, which magnify the
image by refracting (bending) the light
• The minimum resolution of an LM is about
200 nanometers (nm), the size of a small
bacterium
4. Figure
6.2
10 m
1 m
0.1 m
1 cm
1 mm
100 µm
10 µm
1 µm
100 nm
10 nm
1 nm
0.1 nm Atoms
Small molecules
Lipids
Proteins
Ribosomes
Viruses
Smallest bacteria
Mitochondrion
Most bacteria
Nucleus
Most plant and
animal cells
Human egg
Frog egg
Chicken egg
Length of some
nerve and
muscle cells
Human height
Unaidedeye
LM
EM
Super-
resolution
microscopy
•LMs can magnify
effectively to about
1,000 times the size
of the actual
specimen
6. 1 µm
1 µm
Scanning electron
microscopy (SEM) Cilia
Longitudinal
section of
cilium
Transmission electron
microscopy (TEM)
Cross section
of cilium
• 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 3D
• Transmission electron
microscopes (TEMs)
focus a beam of
electrons through a
specimen
• TEMs are used mainly to
study the internal
ultrastructure of cells
8. Isolating Organelles by Cell
Fractionation
• Cell fractionation takes cells apart and separates the major
organelles from one another
• Ultracentrifuges fractionate cells into their component
parts
Homogenization
Homogenate
Tissue
cells
Differential centrifugation
9. LE 6-5b
Pellet rich in
nuclei and
cellular debris
Pellet rich in
mitochondria
(and chloro-
plasts if cells
are from a plant)
Pellet rich in
“microsomes”
(pieces of plasma
membranes and
cells’ internal
membranes)
Pellet rich in
ribosomes
150,000 g
3 hr
80,000 g
60 min
20,000 g
20 min
1000 g
(1000 times the
force of gravity)
10 min
Supernatant poured
into next tube
10. Comparing Prokaryotic and
Eukaryotic Cells
• Basic features of all cells:
– Plasma membrane
– Semifluid substance called the cytosol
– Chromosomes (carry genes)
– Ribosomes (make proteins)
13. • Eukaryotic cells have DNA in a nucleus that is
bounded by a membranous nuclear envelope
• Eukaryotic cells have membrane-bound organelles
Name 2 in micrograph above.
• Eukaryotic cells are generally much larger than
prokaryotic cells
Type of microscope? Why?
Animal, plant, bacteria, or fungi? Why?
14. LE 6-7
Total surface area
(height x width x
number of sides x
number of boxes)
6
125 125
150 750
1
1
1
5
1.2 66
Total volume
(height x width x length
X number of boxes)
Surface-to-volume
ratio
(surface area ÷ volume)
Surface area increases while
Total volume remains constant
The logistics of carrying
out cellular metabolism
sets limits on the size of
cells
15. Hydrophilic
region
Hydrophobic
region
Carbohydrate side chain
Structure of the plasma membrane
Hydrophilic
region
Phospholipid Proteins
Outside of cell
Inside of cell 0.1 µm
TEM of a plasma membrane
•The plasma membrane is a selective barrier that allows sufficient
passage of oxygen, nutrients,
and waste to service the volume of the cell
•The general structure of a biological membrane is a double layer of
phospholipids
19. The Nucleus: Genetic Library of
the Cell
• 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
20. LE 6-10
Close-up of nuclear
envelope
Nucleus
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore
complex
Ribosome
Pore complexes (TEM) Nuclear lamina (TEM)
1 µm
Rough ER
Nucleus
1 µm
0.25 µm
Surface of nuclear envelope
21. Ribosomes: Protein Factories in
the Cell
• Ribosomes are particles made 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
(ER) or the nuclear envelope (bound
ribosomes)
22. LE 6-11
Ribosomes
0.5 µm
ER Cytosol
Endoplasmic
reticulum (ER)
Free ribosomes
Bound ribosomes
Large
subunit
Small
subunit
Diagram of
a ribosome
TEM showing ER
and ribosomes
23. Concept 6.4: 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 via transfer by vesicles
Inner life of a cell
24. 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, which lacks ribosomes
– Rough ER, with ribosomes studding its surface
25. LE 6-12
Ribosomes
Smooth ER
Rough ER
ER lumen
Cisternae
Transport vesicle
Smooth ER Rough ER
Transitional ER
200 nm
Nuclear
envelope
26. • The smooth ER
– Synthesizes lipids
– Metabolizes carbohydrates
– Stores calcium
– Detoxifies poison (organ with
cells loaded with smooth ER?)
• The rough ER
– Has bound ribosomes
– Produces proteins and
membranes, which are
distributed by transport
vesicles
– Is a membrane factory for the
cell
28. LE 6-13
trans face
(“shipping” side of
Golgi apparatus) TEM of Golgi apparatus
0.1 µm
Golgi
apparatus
cis face
(“receiving” side of
Golgi apparatus)
Vesicles coalesce to
form new cis Golgi cisternaeVesicles also
transport certain
proteins back to ER
Vesicles move
from ER to Golgi
Vesicles transport specific
proteins backward to newer
Golgi cisternae
Cisternal
maturation:
Golgi cisternae
move in a cis-
to-trans
direction
Vesicles form and
leave Golgi, carrying
specific proteins to
other locations or to
the plasma mem-
brane for secretion
Cisternae
29. Lysosomes: Digestive
Compartments
• A lysosome is a membranous sac of
hydrolytic enzymes
• Lysosomal enzymes can hydrolyze proteins,
fats, polysaccharides, and nucleic acids
• Lysosomes also use enzymes to recycle
organelles and macromolecules, a process
called autophagy
31. Vacuoles: Diverse Maintenance
Compartments
• Vesicles and vacuoles (larger versions of
vacuoles) are membrane-bound sacs with varied
functions
• A plant cell or fungal cell may have one or
several vacuoles
• 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
32. LE 6-15
5 µm
Central vacuole
Cytosol
Tonoplast
Central
vacuole
Nucleus
Cell wall
Chloroplast
Video: Paramecium VacuoleVideo: Paramecium Vacuole
33. Concept 6.5: Mitochondria and
chloroplasts change energy from one
form to another
• Mitochondria are the sites of cellular respiration
• Chloroplasts, found only in plants and algae, are
the sites of photosynthesis
• Mitochondria and chloroplasts are not part of the
endomembrane system
• Peroxisomes are oxidative organelles
34. The Evolutionary Origins of
Mitochondria and Chloroplasts
• Mitochondria and chloroplasts have
similarities with bacteria
– Enveloped by a double membrane
– Contain free ribosomes and circular double
stranded DNA molecules
– Grow and reproduce somewhat independently
in cells
• These similarities led to the
endosymbiont theory
35. • The endosymbiont theory suggests that
an early ancestor of eukaryotes engulfed
an oxygen-using nonphotosynthetic
prokaryotic cell
• The engulfed cell formed a relationship
with the host cell, becoming an
endosymbiont
• The endosymbionts evolved into
mitochondria
• At least one of these cells may have then
taken up a photosynthetic prokaryote,
which evolved into a chloroplast
36. Figure 6.16
Endoplasmic
reticulum
Nucleus
Nuclear
envelope
Ancestor of
eukaryotic cells (host cell)
Engulfing of oxygen-
using nonphotosynthetic
prokaryote, which
becomes a mitochondrion
Nonphotosynthetic
eukaryote
Engulfing of
photosynthetic
prokaryote
Mitochondrion
Mitochondrion
Chloroplast
Photosynthetic eukaryote
At least
one cell
37. 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
39. Chloroplasts: Capture of Light
Energy
• The chloroplast is a member of a family of
organelles called plastids
• 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
• Chloroplast structure includes:
– Thylakoids, membranous sacs
– Stroma, the internal fluid
40. Figure 6.18
Chloroplast
Ribosomes Stroma
Inner
and outer
membranes
Granum
DNA
Thylakoid Intermembrane space
Diagram and TEM of chloroplast(a) (b) Chloroplasts in an
algal cell
(b)
1 μm
50 μm
Chloroplasts
(red)
41. Peroxisomes: Oxidation
• Peroxisomes are specialized metabolic
compartments bounded by a single membrane
• Peroxisomes produce hydrogen peroxide and
convert it to water
Chloroplast
Peroxisome
Mitochondrion
42. • The cytoskeleton is a network of fibers
extending throughout the cytoplasm
• It organizes the cell’s structures and
activities, anchoring many organelles
• It is composed of three types of molecular
structures:
– Microtubules (red)
– Microfilaments (green)
– Intermediate filaments (yellow)
44. Roles of the Cytoskeleton: Support,
Motility, and Regulation
• The cytoskeleton helps to support the cell
and maintain its shape
• It interacts with motor proteins to produce
motility
• Inside the cell, vesicles can travel along
“monorails” provided by the cytoskeleton
• Recent evidence suggests that the
cytoskeleton may help regulate biochemical
activities
45. Figure
6.21
0.25 μmVesiclesMicrotubule
SEM of a squid giant axon(b)
(a) Motor proteins “walk” vesicles along cytoskeletal
fibers.
(a)
Motor protein
(ATP powered)
Microtubule
of cytoskeleton
Receptor for
motor protein
Vesicle
ATP
46.
47.
48.
49. Microtubules
• Microtubules are hollow rods about 25 nm in
diameter and about 200 nm to 25 microns
long
• Functions of microtubules:
– Shaping the cell
– Guiding movement of organelles
– Separating chromosomes during cell division
Cross-section MT
51. Centrosomes and Centrioles
• In many cells, microtubules grow out from a
centrosome near the nucleus
• The centrosome is a “microtubule-
organizing center”
• In animal cells, the centrosome has a pair of
centrioles, each with nine triplets of
microtubules arranged in a ring
54. Cilia and Flagella
• Microtubules control the
beating of cilia and flagella,
locomotor appendages of
some cells
• Cilia and flagella differ in
their beating patterns
Video: ChlamydomonasVideo: Chlamydomonas
Video: Paramecium CiliaVideo: Paramecium Cilia
Cilia in inner ear
56. LE 6-23b
15 µm
Direction of organism’s movement
Motion of cilia
Direction of
active stroke
Direction of
recovery stroke
57. • Cilia and flagella share a common
ultrastructure:
– 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
58. Figure 6.240.1 μm
0.5 μm
0.1 μm
Microtubules
Plasma
membrane
Basal
body
Longitudinal section
of motile cilium
(a)
Triplet
Cross section of
motile cilium
(b)
Outer microtubule
doublet
Motor proteins
(dyneins)
Central
microtubule
Radial spoke
Cross-linking
proteins between
outer doublets
Plasma
membrane
Cross section of basal body(c)
59. • How dynein “walking” moves flagella and
cilia:
– Dynein arms alternately grab, move, and
release the outer microtubules
– Protein cross-links limit sliding
– Forces exerted by dynein arms cause doublets
to curve, bending the cilium or flagellum
62. Microfilaments (Actin Filaments)
• Microfilaments are solid rods about 7 nm in
diameter, built as a twisted double chain of actin
subunits
• The structural role of microfilaments is to bear
tension, resisting pulling forces within the cell
• They form a 3D network just inside the plasma
membrane to help support the cell’s shape
• Bundles of microfilaments make up the core of
microvilli of intestinal cells
64. • Microfilaments that function in cellular
motility contain the protein myosin in
addition to actin
• In muscle cells, thousands of actin filaments
are arranged parallel to one another
• Thicker filaments composed of myosin
interdigitate with the thinner actin fibers
65. Figure 6.26
Muscle cell
0.5 µm
Actin
filament
Myosin
filament
Myosin
head Chloroplast
(a)
(b)
(c)Myosin motors in muscle cell contraction Cytoplasmic streaming in
plant cells
Amoeboid movement
Extending
pseudopodium
Cortex (outer cytoplasm):
gel with actin network
Inner cytoplasm
(more fluid)
100 µm
30 µm
66. • Localized contraction brought about by
actin and myosin also drives amoeboid
movement
• Pseudopodia (cellular extensions) extend
and contract through the reversible
assembly and contraction of actin subunits
into microfilaments
67. LE 6-27b
Cortex (outer cytoplasm):
gel with actin network
Amoeboid movement
Inner cytoplasm: sol
with actin subunits
Extending
pseudopodium
68. • Cytoplasmic streaming is a circular flow of
cytoplasm within cells
• This streaming speeds distribution of
materials within the cell
• In plant cells, actin-myosin interactions and
sol-gel transformations drive cytoplasmic
streaming
Video: Cytoplasmic StreamingVideo: Cytoplasmic Streaming
70. Intermediate Filaments
• Intermediate filaments range in diameter
from 8–12 nanometers, larger than
microfilaments but smaller than
microtubules
• They support cell shape and fix organelles
in place
• Intermediate filaments are more permanent
cytoskeleton fixtures than the other two
classes
71. Concept 6.7: 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 structures include:
– Cell walls of plants
– The extracellular matrix (ECM) of animal cells
– Intercellular junctions
72. Cell Walls of Plants
• The cell wall is an extracellular structure
that distinguishes plant cells from animal
cells
• 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
73. Cell Walls of Plants
• 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
75. 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
and other macromolecules. ECM proteins
bind to receptor proteins in the plasma
membrane called integrins.
• Functions of the ECM:
– Support
– Adhesion
– Movement
– Regulation
80. 6.33 Role of the extracellular matrix in cell differentiation
Basal lamina in
B induces
differentiation
81. Intercellular Junctions
• Neighboring cells in tissues, organs, or
organ systems often adhere, interact, and
communicate through direct physical
contact
• Intercellular junctions facilitate this contact
82. Plants: Plasmodesmata
• 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
Cross-section
84. Animals: Tight Junctions,
Desmosomes, and Gap Junctions
• At tight junctions, membranes of neighboring cells
are pressed together, preventing leakage of
extracellular fluid
• Desmosomes (anchoring junctions) fasten cells
together into strong sheets
• Gap junctions (communicating junctions) provide
cytoplasmic channels between adjacent cells
85. LE 6-31
Tight junctions prevent
fluid from moving
across a layer of cells
Tight junction
0.5 µm
1 µm
0.1 µm
Gap junction
Extracellular
matrix
Space
between
cells
Plasma membranes
of adjacent cells
Intermediate
filaments
Tight junction
Desmosome
Gap
junctions
88. Connexin proteins create gap junctions
6 connexins/channel
A compartment of several cells
In center
89. The Cell: A Living Unit Greater Than
the Sum of Its Parts
• Cells rely on the integration of structures
and organelles in order to function
• Inner Life of A Cell
90. Nuclear Pore Complex is much more
complicated than just a simple
protein like the connexin protein of
gap junctions—Groups of scientists
are uncovering just how many
proteins interact to make up this
complex.
http://lab.rockefeller.edu/rout/resproj1
Editor's Notes
Figure 6.2 The size range of cells
Figure 6.3 Exploring microscopy
Concept Check 6.1
1. How do stains used for light microscopy compare with those used for electron microscopy?
➢Stains used for light microscopy are colored molecules that bind to cell components, affecting the light passing through, while stains used for electron microscopy involve heavy metals that affect the beams of electrons passing through
2. Which type of microscope would you use to study (a) the changes in shape of a living white blood cell and (b) the details of surface texture of a hair?
➢ a) light microscope (no damage to cell) b) scanning electron microscope (to study the detailed architecture of cell surfaces)
Both the SEM and TEM use electromagnets as lenses to bend the paths of the electrons, ultimately focusing the image onto a monitor for viewing.
Freeze fracture: making the specimen cold and then breaking it. Pic C has a flat surface of the membrane.
We’ve had separation via chromatography, polarity before. Now we can do it via centrifugation. It is actually common.
Application Cell fractionation is used to isolate (fractionate) cell components based on size and density.
Technique Cells are homogenized in a blender to break them up. The resulting mixture (homogenate) is centrifuged. The supernatant (liquid) is poured into another tube and centrifuged at a higher speed for a longer period. This process is repeated several times. This “differential centrifugation” results in a series of pellets, each containing different cell components.
➢The faster the centrifuge spins the smaller the pellets will be
Cell fractionation enables researchers to prepare specific cell components in bulk and identify their functions, a task not usually possible with intact cells.
Write an essay about these four common features in ALL cells
Figure 6.5 A prokaryotic cell
Bacteria have a cell wall (peptidoglycan is only present in cell walls)
Classification based on the type of cell wall (done via gram stain)
Thick Peptidoglycan Layer-- Cell Wall are long strains of sugar. Gram Positive absorb the stain and turn purple
N-acetylglucosamine (NAG)
N-acetylnuramic acid (NAM)
Thin Peptidoglycan Cell Wall – gram negative cell wall is composed of a thin layer plus an outer layer (more complex structure than Gram positive)
Right outside the plasma membrane is a cell wall.
Plasma membrane controls what goes in and out of the cell
Cell wall provides structure and keeps protection via osmotic pressure
Capsule (not on all bacteria) is a thick coating outside of the cell wall and secrete capsules to
Not involved in immune response
2 types-- simple polysaccharides which don’t elicit an immediate response
Ribosomes: different in eukaryotic (ads) than bacteria (7ds)
Prokaryotic Fimbriae: made of the protein pilin. Used to attach to other things—function.
Chromosomes: “blueprint to life”coding for all of the biological models than need to be made and passes it down from cell to cell
Flagella: have little embedded motors causing them to twirl. Function is for movement Clockwise twirl = forward counter
Sex Pilis: to pass a small portion of the genome. bacterial conjugation made by male bacteria composed of pillin
Transmission Electron Microscope because it’s a slice and you can see the cell
Animal Cell
Nuclear Envelope: protein and phospholipids. Function is to house the genetic material
Eukaryotic cells have compartmentalization that allow them to have bigger cells
Compartments = organelles
A high surface-to-volume ratio facilitates the exchange of materials between a cell and its environment.
Figure 6.8a Exploring eukaryotic cells (part 1: animal cell cutaway)
Concept Check 6.2
1 Briefly describe the structure and function of the nucleus, the mitochondrion, the chloroplast, and the endoplasmic reticulum.
➢Nucleus: Nuclear envelope: is a double membrane enclosing the nucleus; perforated by pores; continuous with ER.
Nucleolus: structure involved in production of ribosomes; a nucleus has one or more nucleoli.
Chromatin: material consisting of DNA and proteins; visible as individual chromosomes in a dividing cell
Mitochondrion: organelle where cellular respiration occurs and most ATP is generated; double-bound membrane; folded inner membrane; has some individual DNA
Chloroplast: photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules; double bound membrane; inner thylakoids; individual DNA
ER: network of membranous sacs and tubes; active in membrane synthesis and other synthetic ad metabolic processes; has rough (ribosomal studded) and smooth regions
2. Imagine an elongated cell (such as a nerve cell) that measures 125 * 1 * 1 arbitrary units. Predict how its surface-to-volume ratio would compare with thosein Figure 6.7.Then calculate the ratio and check your prediction.
➢This cell would have the same volume as the cells in columns 2 and 3 but proportionally more surface area than in column 2 and less than in column 3. Thus, the surface-to-volume ratio should be greater than 1.2 but less than 6. To obtain the surface area, you'd have to add he area of the six sides 125 +125 +125 +125+1+1 = 502. The surface-to-volume ratio equals 502 divided by a volume of 125, or 4.0
The nucleus houses most of the cell’s DNA and Ribosomes. (Some genes are located in mitochondria and chloroplasts.)
➢use information from the DNA to make proteins
➢DNA is organized into discrete units called chromosomes
Mitochondria, Chloroplast, and Nucleus have a double membrane.
➢chromatin: The complex of DNA and proteins making up chromosomes
➢nucleolus: nuclear subdomain that assembles ribosomal subunits.
proteins imported from the cytoplasm are assembled with rRNA into large
and small subunits of ribosomes.
The nucleus directs protein synthesis by synthesizing messenger RNA (mRNA) according to instructions provided by the DNA. Once an mRNA molecule reaches the cytoplasm, ribosomes translate the mRNA’s genetic message into the primary structure of a specific polypeptide.
➢ribosomes are not membrane bounded and thus are not considered organelles.
➢cells active in protein synthesis also have prominent nucleoli
Endomembrane System Carries out many tasks:
➢synthesis of proteins
➢transport of proteins into membranes and organelles or out of the cell
➢metabolism and movement of lipids
➢detoxification of poisons
Vesicles: sacs made of membrane
Smooth ER: outer surface lacks ribosomes
➢Functions include: synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions.
➢
Rough ER: studded with ribosomes on the outer surface of the membrane, thus appearing “rough” through an electron microscope
➢membrane factory for the cell–it grows in place by adding membrane proteins and phospholipids to its own mem- brane.
➢glycoproteins: proteins with carbohydrates covalently bonded to them… most secretory proteins
Cis: Receiving; located near the ER
Trans: Shipping; gives rise to vesicles that pinch off and travel to other sites.
Products of the endoplasmic reticulum are usually modified during their transit from the cis region to the trans region of the Golgi apparatus.
Figure 6.13 Lysosomes
Chloroplast transfer solar energy from the sun to chemical energy.
Mitochondria is where cellular respiration occurs.
Endosymbiotic Theory
Figure 6.16 The endosymbiont theory of the origins of mitochondria and chloroplasts in eukaryotic cells
Figure 6.17 The mitochondrion, site of cellular respiration
Figure 6.18 The chloroplast, site of photosynthesis
Thylakoid Stack = Granum
Stromo: bat
Intermediate filaments are composed of a variety of proteins
Microtubules are made of tubulin
TEM because the resolution is too good for it to be SEM
Figure 6.21 Motor proteins and the cytoskeleton
Microtubule
Large, alpha and beta tubulin, cilia, flagella, and the spindle body are composed of microtubules
Responsible for cell and organelle movements
Microfilaments
Eukaryotic Cilia and Flagella have the 9+2
A lysosome is a vesicle that has a specific job
The basal body has nine triplets, anchors the organelle in the plasma membrane
The flagella and cilia have microtubules columns in the middle
Figure 6.24 Structure of a flagellum or motile cilium
Intermediate filaments are thicker than microfilaments