http://explore.ecb.org/videos/VLC_file?TYPE=Image&P1=2080&REFER
ER=OTHER http://t2.gstatic.com/images?q=tbn:ANd9GcTB6YQWcF9pYillWplUSjw
LeaYe9b6DpWQa5EnlY_oZHbJGcx_00w
Developments in scientific research follow improvements in apparatus—the invention of electron microscopes led to greater understanding of cell structure.
Diana Carvajal
August 2014

Electron microscopes have a much higher resolution than light microscopes.
https://www.classzone.com/books/ml_science_share/vis_sim/chm05_pg19_microscope/chm05_pg19_microscope.swf
http://web.biosci.utexas.edu/psaxena/MicrobiologyAnimations/Animations/Microscopy/micro_microscopy.swf

1. Molecules (1nm).
2. Cell membrane thickness
(10nm).
3. Virus (100nm).
4. Bacteria (1um).
5. Organelles (less 10um).
6. Cells (<100 um).
7. Generally plant cells are larger than animal cells. nm = nanometer
μm = micrometer http://intranet.canacad.ac.jp:3445/BiologyIBHL1/550

• Absence of organelles.
• There is no true nucleus.
• Some bacteria have flagellum.

Ultrastructure of E. coli.
(With naked DNA)
70S
Prokaryotes have a simple cell structure without compartmentalization.
Drawing of the ultrastructure of prokaryotic cells based on electron micrographs

What are the functions of these prokaryotic cell parts?

Binary fission:
• Asexual method of reproduction.
• The cells produced are genetically identical (clones).
Prokaryotes divide by binary fission

1
Eukaryotic cell
2
8
7
6
5
3
4
Eukaryotes have a compartmentalized cell structure.
Drawing of the ultrastructure of eukaryotic cells based on electron micrographs.

Which structures can you identify in this falsecoloured TEM
(transmission electron microscopy) image?

Electron micrographs of liver cells.

Magnification x47,500 at 10X8 cm size.
http://www.sciencephoto.com/media/214698/enlarge

Magnification x47,500 at 10X8 cm size.
ribosomes endoplasmic reticulum (ER) mitochondria
Nuclear membrane
Nucleus http://www.sciencephoto.com/media/214698/enlarge
Electron micrographs of liver cells.

http://www.ucmp.berkeley.edu/alllife/eukaryotamm.html

What are the differences between prokaryotic and eukaryotic cells?
Comparison of prokaryotic and eukaryotic cells

Identify structures in electron micrographs of E. coli