1. Eukaryotic cells have organelles.
The chief distinguishing feature of eukaryotic cells is the presence of a nucleus, a membrane-bound structure that contains linear strands of DNA. In addition to a nucleus, eukaryotic cells usually contain in their cytoplasm several other specialized structures, called organelles, many of which are enclosed separately within their own lipid membranes. Eukaryotic cells are also about 10 times larger than prokaryotes. All of these physical differences make it easy to distinguish eukaryotes from prokaryotes under a microscope (Figure 3-5 Comparison of eukaryotic and prokaryotic cells).  1

2. Eukaryotic Cells Eukaryotes differ from prokaryotes in several ways:
1) separation of nucleus from cytoplasm by double membrane (nuclear envelope)
2) DNA organized into distinct chromosomes (X-shaped)
3) complex membrane-bound organelles (e.g., mitochondria)

3. Three Functional Categories of Eukaryotic Organelles
Manufacturing
Nucleus – genetic control center
- DNA & RNA synthesis and ribosome assemble
ribosomes: assemble amino acids into polypeptides (proteins/enzymes)

5. Three Functional Categories of Eukaryotic Organelles
Manufacturing
Rough Endoplasmic Reticulum
(Rough ER)
- network of interconnected membrane- bound sacs
- “rough” appearance because ribosomes stuck to membrane surface

8. Three Functional Categories of Eukaryotic Organelles
Manufacturing
Golgi Apparatus (GA)
“cell’s warehouse/factory”
- stacks of membrane-bound sacs
- work in close association with ER
- receive, store, modify products of ER

10. Three Functional Categories of Eukaryotic Organelles
2) Breakdown of Material
Lysosomes
- produced by Rough ER & GA
- digest nutrients within cell
Vacuoles
- plant cells
- digest nutrients & storage sac

11. Three Functional Categories of Eukaryotic Organelles
3) Energy Processing
Chloroplasts
- plant cells
- site of photosynthesis
- absorb sun light & transform this energy to food
- light absorbed in grana (stacked “solar packs”)

13. Three Functional Categories of Eukaryotic Organelles
3) Energy Processing
Mitochondria – “cell powerhouse”
- cellular respiration
- double membrane
- folds (cristae) of inner membrane
- matrix is the inner fluid

15. Advantages of membrane-bound organelles
1. compartments
2. unique chemistry in different compartments
3. membranes themselves have enzymes embedded)
4. provides localized environment

16. Advantages of membrane-bound organelles
1. compartments
2. unique chemistry in different compartments
3. membranes themselves have enzymes embedded)
4. provides localized environment

17. Origin of Eukaryotic Cells from Prokaryotes – Additional Evidence Supporting the Endosymbiotic Hypothesis
1. Mitochondria and Chloroplasts contain DNA and ribosomes similar to bacteria
2.Double membrane
3. Circular DNA
4. Looks like bacteria
5. Reproduces by binary fission

18. Road to Modern Organisms
1st life was bacteria unicellular prokaryotes
Photosynthesis changed Earth’s atmosphere released O2 - cyanobacteria!!!!
2nd was unicellular eukaryotes Endosymbiotic Theory
3rd was multicellular organisms

19. Origin of Eukaryotic cells
The endosymbiotic theory is a theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms