A Tour of the Cell

1
Chapter 6 A Tour of the Cell
2
The Beginning
Leeuwenhoeks Microscope
Hookes Microscope
3
The Light Microscope
4
Micrograph from Light Microscope
Euglena, LM 1000X
5
Resolution
6
The Electron Microscope
7
Micrograph from Transmission Electron Microscope
8
Micrograph from Scanning Electron Microscope
9
(No Transcript)
10
(No Transcript)
11
Cell Theory

• All organisms are made of cells
• All cells come from cells

12
Fig. 6-5
Cell Fractionation
13
Some features are the same in all cells

• Plasma membrane
• Cytoplasm
• DNA
• - Eukaryotes DNA is in nucleus
• - Prokaryotes DNA is in nucleoid region
• Ribosomes

14
Prokaryotes vs. Eukaryotes

• DNA Location
• Proks nucleoid region
• Euks nucleus
• Organelles
• Proks no true organelles (no internal membranes)
• Euks membrane-bound organelles
• Size
• Proks smaller
• Euks larger

15
(No Transcript)
16
Fig. 6-8
Does size matter?
17
Fig. 6-6
Prokaryotic Cells
18
Organisms with eukaryotic cells

• Animals
• Plants
• Fungi
• Protists

19
Fig. 6-9a
Nuclear envelope
ENDOPLASMIC RETICULUM (ER)
NUCLEUS
Nucleolus
Smooth ER
Rough ER
Flagellum
Chromatin
Centrosome
Plasma membrane
CYTOSKELETON
Animal Cell
Microfilaments
Intermediate filaments
Microtubules
Ribosomes
Microvilli
Golgi apparatus
Peroxisome
Mitochondrion
Lysosome
20
Fig. 6-9b
Rough endoplasmic reticulum
Nuclear envelope
Nucleolus
NUCLEUS
Chromatin
Smooth endoplasmic reticulum
Ribosomes
Central vacuole
Golgi apparatus
Plant Cell
Microfilaments
Intermediate filaments
CYTO- SKELETON
Microtubules
Mitochondrion
Peroxisome
Chloroplast
Plasma membrane
Cell wall
Plasmodesmata
Wall of adjacent cell
21
Fig. 6-10
Nucleus
22
Fig. 6-11
Ribosome
23
Endomembrane System Overview
24
Fig. 6-12
Endoplasmic Reticulum (ER)
25
Smooth ER

• Three functions of the Smooth ER
• Lipid production
• Detoxifying enzymes
• Calcium ion storage

26
Rough ER

• Two functions of the Rough ER
• Membrane production
• Protein modification

27
(No Transcript)
28
Fig. 6-13
Golgi Apparatus (Golgi Complex)
cis face (receiving side of Golgi apparatus)
0.1 µm
Cisternae
trans face (shipping side of Golgi apparatus)
TEM of Golgi apparatus
29
Fig. 6-14
Lysosome
1 µm
Nucleus
Vesicle containing two damaged organelles
1 µm
Mitochondrion fragment
Peroxisome fragment
Lysosome
Digestive enzymes
Lysosome
Lysosome
Plasma membrane
Peroxisome
Digestion
Food vacuole
Digestion
Mitochondrion
Vesicle
(a) Phagocytosis
(b) Autophagy
30
Fig. 6-15
Central vacuole
Cytosol
Vacuole
Central vacuole
Nucleus
Cell wall
Chloroplast
5 µm
31
Fig. 6-16-1
Nucleus
Rough ER
Smooth ER
Plasma membrane
32
Fig. 6-16-2
Nucleus
Rough ER
Smooth ER
cis Golgi
Plasma membrane
trans Golgi
33
Fig. 6-16-3
Nucleus
Rough ER
Smooth ER
cis Golgi
Plasma membrane
trans Golgi
34
Mitochondria Powerhouse of the Cell

• Mitochondria are divided into two compartments
  (separated by the innermembrane)
• Intermembrane space
• Mitochondrial matrix

35
Fig. 6-17
Mitochondria Powerhouse of the Cell
Intermembrane space
Outer membrane
Free ribosomes in the mitochondrial matrix
Inner membrane
Cristae
Matrix
0.1 µm
36
Chloroplasts Site of Photosynthesis

• Converts solar energy into chemical energy
• Chloroplasts are divided into three compartments
• Intermembrane space
• Stroma
• Grana

37
Fig. 6-18
Chloroplasts Site of Photosynthesis
Ribosomes
Stroma
Inner and outer membranes
Granum
1 µm
Thylakoid
38
Fig. 6-19
Chloroplast
Peroxisome
Mitochondrion
1 µm
39
Cytoskeleton

• Microfilaments thinnest
• Intermediate filaments
• Microtubules thickest

40
Table 6-1
10 µm
10 µm
10 µm
Column of tubulin dimers
Keratin proteins
Actin subunit
Fibrous subunit (keratins coiled together)
25 nm
7 nm
812 nm
Tubulin dimer
?
?
41
Fig. 6-23
Direction of swimming
(a) Motion of flagella
5 µm
Cilia and Flagella
Direction of organisms movement
Power stroke
Recovery stroke
(b) Motion of cilia
15 µm
42
Fig. 6-24
Outer microtubule doublet
Plasma membrane
0.1 µm
Dynein proteins
Central microtubule
Radial spoke
Protein cross-linking outer doublets
Microtubules
(b)
Cross section of cilium
Plasma membrane
Basal body
0.5 µm
0.1 µm
(a)
Longitudinal section of cilium
Triplet
(c) Cross section of basal body
43
Fig. 6-28
Secondary cell wall
Primary cell wall
Middle lamella
1 µm
Central vacuole
Cytosol
Plasma membrane
Plant cell walls
Plasmodesmata
44
Fig. 6-30
Polysaccharide molecule
Proteoglycan complex
Collagen
EXTRACELLULAR FLUID
Carbo- hydrates
Fibronectin
Core protein
Integrins
Proteoglycan molecule
Plasma membrane
Proteoglycan complex
CYTOPLASM
Micro- filaments
45
Fig. 6-32
Tight junction
Tight junctions prevent fluid from moving across
a layer of cells
0.5 µm
Tight junction
Intermediate filaments
Desmosome
Desmosome
Gap junctions
1 µm
Extracellular matrix
Space between cells
Gap junction
Plasma membranes of adjacent cells
0.1 µm
46
Fig. 6-UN1
Cell Component
Structure
Function
Houses chromosomes, made of chromatin (DNA, the
genetic material, and proteins)
contains nucleoli, where ribosomal subunits are
made. Pores regulate entry and exit of materials.
Nucleus
Concept 6.3
Surrounded by nuclear envelope (double
membrane) perforated by nuclear pores. The
nuclear envelope is continuous with
the endoplasmic reticulum (ER).
The eukaryotic cells genetic instructions are
housed in the nucleus and carried out by the
ribosomes
(ER)
Ribosome
Two subunits made of ribo- somal RNA and
proteins can be free in cytosol or bound to ER
Protein synthesis
Extensive network of membrane-bound tubules
and sacs membrane separates lumen from
cytosol continuous with the nuclear envelope.
Concept 6.4
Endoplasmic reticulum
Smooth ER synthesis of lipids, metabolism of
carbohy- drates, Ca2 storage, detoxifica-tion of
drugs and poisons
The endomembrane system regulates protein traffic
and performs metabolic functions in the cell
(Nuclear envelope)
Rough ER Aids in synthesis of secretory and
other proteins from bound ribosomes
adds carbohydrates to glycoproteins produces new
membrane
Modification of proteins, carbo- hydrates on
proteins, and phos- pholipids synthesis of
many polysaccharides sorting of Golgi products,
which are then released in vesicles.
Golgi apparatus
Stacks of flattened membranous sacs has
polarity (cis and trans faces)
Breakdown of ingested substances, cell
macromolecules, and damaged organelles for
recycling
Lysosome
Membranous sac of hydrolytic enzymes (in animal
cells)
Digestion, storage, waste disposal, water
balance, cell growth, and protection
Vacuole
Large membrane-bounded vesicle in plants
Concept 6.5
Mitochondrion
Bounded by double membrane inner membrane
has infoldings (cristae)
Cellular respiration
Mitochondria and chloro- plasts change energy
from one form to another
Chloroplast
Typically two membranes around fluid stroma,
which contains membranous thylakoids stacked into
grana (in plants)
Photosynthesis
Contains enzymes that transfer hydrogen to water,
producing hydrogen peroxide (H2O2) as
a by-product, which is converted to water by
other enzymes in the peroxisome
Peroxisome
Specialized metabolic compartment bounded by
a single membrane
47
(No Transcript)