Post on 27-Dec-2015
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Cell Structure and Function
Kandinsky (1866-1944)
Early Observations
• Santiago Ramon y Cajal (1852-19340
• Mid 1600s - Robert
Hooke cells in cork
• Late 1600s - Antony
van Leeuwenhoek,
microorganisms
Early Discoveries
Early Discoveries
• 1820s - Robert Brown observed
nucleus in plant cells
Microscopes
• Light microscopes• Magnify to 1,000X
LM 1
,000
Figure 4.1B
• Greater magnification
SE
M 2
,000
TE
M 2
,800
Figure 4.1C Figure 4.1D
Electron Microscope
• Cells vary • Surface area - limits
Human height
Length of somenerve andmuscle cells
Chicken egg
Frog egg
Un
aid
ed e
ye
Lig
ht m
icro
sco
pe
Ele
ctro
n m
icro
scop
e
10 m
1 m
100 mm(10 cm)
10 mm(1 cm)
1 mm
100 m
10 m
1 m
100 nm
10 nm
1 nm
0.1 nmAtoms
Proteins
Small molecules
Lipids
Viruses
Ribosome
Nucleus
Mycoplasmas(smallest bacteria)
Most plant andanimal cells
Most bacteria
Mitochondrion
Cell Size
– Ratio of surface area to volume
30 m 10 m
30 m 10 m
Surface areaof one large cube 5,400 m2
Total surface areaof 27 small cubes 16,200 m2Figure 4.2B
Cell Size
Cell Theory
1) Every organism is composed of
cells
2) Cell is smallest unit of life
3) Continuity of life from cells growth
+ division
Structure of Cells
• Two types
• Prokaryotic - bacteria– No nucleus
– DNA?
Prokar yoticflagella
Ribosomes
Capsule
Cell wall
Plasmamembrane
Nucleoid region (DNA)
Pili
Structure of Cells
• Eukaryotic – plants, animals, fungi– DNA?
Structure of Cells
Prokaryotic cell
Nucleoidregion
Nucleus
Eukar yotic cell Organelles
Co
loriz
ed
TE
M 1
5,0
00
Eukaryotic Cells• Nucleus and
organellesNucleus
Smooth endoplasmicreticulum
Roughendoplasmicreticulum
Ribosomes
Golgiapparatus
Plasma membrane
Mitochondrion
Flagellum
Not in mostplant cells Lysosome
Centriole
Microtubule
CytoskeletonIntermediatefilament
Microfilament
Peroxisome
Plant Cell Features
CentralvacuoleNot in
animalcells
Chloroplast
Cell wall
Golgiapparatus
Nucleus
Microtubule
CytoskeletonIntermediatefilament
Microfilament
Ribosomes
Smoothendoplasmicreticulum
Mitochondrion
Peroxisome
Plasma membrane
Roughendoplasmicreticulum
Components of the Nucleus
NucleusChromatin
Nucleolus
Pore
Ribosomes
Roughendoplasmicreticulum
Two membranesof nuclearenvelope
Smooth ER
Rough ER
Nuclearenvelope
Rough ER
Ribosomes
Smooth ER
TE
M 4
5,00
0
Figure 4.7
Smooth ER
Rough ER
Secretory(glyco-) proteininside trans-port vesicle
4Transport vesiclebuds off
Sugar chain
3
Rough ER
Glycoprotein2Polypeptide
Ribosome
1
Golgi apparatus
TE
M 1
30
,00
0
Transportvesicle fromthe Golgi“Shipping” side
of Golgi apparatus
Golgiapparatus
“Receiving” side ofGolgi apparatus
Transportvesiclefrom ER
New vesicleforming
Golgi Apparatus
Vesicles• Lysosomes
Vesicles• Vacuoles
– Central vacuole– Contractile vacuole
Chloroplast
Centralvacuole
Nucleus
Col
oriz
ed T
EM
8,7
00
LM
6
50
Nucleus
Contractilevacuoles
Mitochondria
Mitochondrion
Outermembrane
Intermembranespace
Matrix
Innermembrane
Cristae
TE
M 4
4,8
80
Chloroplasts
TE
M 9
,750
Chloroplast
Stroma
Intermembranespace
Inner and outermembranes
Granum
Figure 4.14
LM
60
0
Co
loriz
ed
SE
M 4
,10
0
Figure 4.17A Figure 4.17B
Flagella and Cilia
Figure 4.17C
Flagellum Electron micrographsof cross sections:
Flagellum
Basal bodyBasal body(structurally identical to centriole)
TE
M 2
06,5
00
TE
M
206,
500
Plasmamembrane
Dynein arms
Radial spoke
Centralmicrotubules
Outer microtubuledoublet
Flagella and Cilia
Cytoskeletal Elements
Actin subunit
Microfilament
7 nm
Fibrous subunits
10 nm
Intermediate filament Microtubule
25 nm
Tubulin subunit
Microtubules
• Involved in plant/ animal interactions
Figure 4.21Page 71
tubulinsubunit
Microfilaments
• Muscle contraction
actinsubunit
Intermediate Filaments
onepolypeptidechain
Plant Cell Walls
• Primary cell wall = outer • Secondary cell wall
– Rigid– Cellulose and lignin
• Middle lamella joins cells together
Plant Cell Walls
Primary cell wall
Secondary cell wall(3 layers)
Plant Cell Walls
Slide 35
plasmamembrane
middle lamella
primarycell wall
plasmodesmata
Figure 4.27bPage 74
Animal Cell Junctions
• Tight junctions– Link cells of most body tissues– Waterproof
• Adhering junctions– Link cells prone to stretching
• Gap junctions– Link cytoplasm - rapid signals
Animal Cell Junctions
tightjunctions
adhering junction
gapjunction
Question of the Day
What is the role of the smooth ER in increasing drug tolerance?