cell biology

1. Cell Biology
S. Rahgozar,PhD
University of Isfahan
Faculty of Science
1. An overview of cells and cell research
1.1. The origin of cells and experimental models
1392-93

2. C
The origin and evolution of cells
o Classification
Prokaryotic cells
Eukaryotic cells

3. Spontaneous formation of organic molecules
The first cell
3.8 billion years ago
750 million years after the formation of Earth
Date?
How?
Spontaneous polymerization of molecules
under existing Earth atmosphere
1950s- Miller

4. Self replication of RNA
1980s- Altman & Cech
RNA is able to
 Act as a template
 Catalyze its own replication

5. Enclosure of Self replicating RNA in a lipid membrane

6. Generation of metabolic energy
The evolution of metabolism

7. Electron micrograph of E.Coli
Classification of Prokaryotes
 Archaebacteria
 Eubacteria
(Present-day bacteria)
(Thermoacidophiles)
 The largest and most complex
prokaryotes are
Cyanobacteria
30,000
ribosomes

8. Eukaryotic cells
Origin
Endosymbiosis
Mitochondria and Chloroplasts
 Are similar in size
 Reproduce by dividing
 Contain their own DNA
which is distinct from the
nuclear genome
 Ribosomes and ribosomal
RNAs are more related to
bacteria

9. Evolution of cells

10. Electron micrograph of
Saccharomyces Cerevisiae
Colonial green algae (Vovox)
Light micrograph of
Amoeba proteus
The development of multicellular organisms

11. Plant cells
Prenchyma cells
Epidermal cells
Vessel elements
Collenchyma cells

12. Animal cells
Fibroblasts
Epithelial cells

13. Cells as experimental models

14.  E.Coli
Photograph of E. Coli bacterial colonies
 Yeasts
Electron micrograph of
Saccharaomyces cervisiae
Doubling time under optimal culture: 20 min
108 cells
Doubling time: 2 h
Genome: 16 linear chromosomes
Contains nuclear membrane

15.  Caenorhabditis elegans
 Drosophila melanogaster
Genes are in
Number
Function
to human genes
similar
Contains:
959 Somatic cells
1000-2000 Germ cells
Reproductive cycle: 2w

16.  Arabidopsis thaliana
 Vertebrates
Contains only about 125 million bps,
but 26,000 genes(15,000)
o More complex genes (10-30 ×)
o More specific cells (150-200 cell types)

17. o Zebrafish
An adult fish
A 24h old embryo
o Xenopus laevis
Eggs of the frog Xenopus laevis

18. o Mouse
Piebaldism (defect in pigmentation) as a result of mutations in a gene required for
normal migration of melanocytes
Mutations in homologous genes result in similar developmental defects