1. History, Types and General Characteristics of Cells Packet #10 Chapter #3 Wednesday, October 21, 20151

2. Cytology Wednesday, October 21, 20152  Cytology is the study of cells.

3. Cell Theory  Various scientists arrived at three major thoughts  All living things are composed of cells  Cells are the basic units of structure and function in living things  All cells come from preexisting cells  These three thoughts became known as the cell theory. Wednesday, October 21, 20153

4. The Discovery Wednesday, October 21, 20154  Cells discovered by Robert Hooke in 1665  However the subcellular structures could not be seen--the organelles  It wasn’t until the 1950’s, with the invention of the electron microscope that cell biology really took off

5. Isolation of Organelles Cell Fractionation  Cell fractionation allowed scientists to study cell components and involves a process known as centrifugation  The centrifuge is an instrument that is used to fractionize cells  Spins fast as much as 80,000 revolutions per minute and apply forces on particles up to 500,000 times the force of gravity  Differential centrifugation separate cellular components based on size and density.  Density gradient centrifugation allows further purification. Wednesday, October 21, 20155

6.  Micromanipulation  Another technique for the removal of parts of the cell  Can also insert material into a living cell  Done while looking through a microscope  In-Vitro Fertilization  In-Vivo Fertilization  Cell Cultures**  Isolate one type of cell and you grow it in large numbers-- bacteria for example Wednesday, October 21, 20156 Isolation of Organelles II Micromanipulation & Cell Cultures

7. SIZE OF ATOMS, MOLECULES, MACROMOLECULES, ORGANELLES, CELLS AND ORGANISMS The Hierarchy Revisited Wednesday, October 21, 20157

8. Hierarchy Revisited Wednesday, October 21, 20158  Why do you think that the size of a cell is significant?  What makes the cell’s size special?  The small cell size allows maximum cell surface area.  HW

9. Introduction of Prokaryotic & Eukaryotic Cells  The discovery of cells, and their components, led to the distinction between prokaryotic cells and eukaryotic cells. Wednesday, October 21, 20159

10. Prokaryotic vs. Eukaryotic Wednesday, October 21, 201510  Prokaryotic Cells  Prokaryotes are structurally simpler than eukaryotic cells.  Prokaryotic cells lack membrane-bound organelles and are typically smaller than eukaryotic cells.  Prokaryotic cells have a plasma membrane and typically a cell wall.  In prokaryotes, DNA is located in the nuclear area or nucleoid.  Prokaryotes have smaller ribosomes.  Chlorophyll may be present but no chloroplasts.  Mitosis, nor meiosis, does not occur  Cells reproduce by other asexual means

11. Prokaryotic versus Eukaryotic II Wednesday, October 21, 201511  Eukaryotic Cells  Membrane bound organelles are present  Nucleus and nuclear membrane are present  Chlorophyll, when present, is contained in chloroplasts  Ribosomes are larger  Cell wall is present in some eukaryotic cells  Mitosis and meiosis occurs

12. Prokaryotic CellsEukaryotic Cells  No distinct nucleus  No chromosomes  Circular strands of DNA known as plastids  No membrane bound organelles  Ribosomes are smaller  No mitosis or meiosis occurs  Distinct, membrane-bounded nucleus  Chromosomes present on which DNA is located  Chloroplasts and mitochondria may be present  Ribosomes are larger  Mitosis and/or meiosis occurs Prokaryotes vs. Eukaryotes Wednesday, October 21, 201512

13. TYPES OF EUKARYOTIC CELLS Plant cells vs. Animal Cells Wednesday, October 21, 201513

14. Eukaryotic Cells Wednesday, October 21, 201514  Most organisms are eukaryotes and are composed of eukaryotic cells.  There are two basic types of eukaryotic cells  Plant cells  Animal cells Organisms Prokaryotic Prokarytic Cells Eukaryotic Eukaryotic Cells Plant Cells Animal Cells Nerve cells Muscle cells Blood cells

15. Plant Cells Wednesday, October 21, 201515  Have cell walls  Contain cellulose  Large vacuole filled with cell sap  Larger than animal cells  Shape  Different from animal cells  Cilia and flagella absent in higher plants  What kingdom(s) are the higher plants found?  What kingdom(s) are the lower plants found?

16. Animal Cells Wednesday, October 21, 201516  No cellulose cell wall in MOST animal cells  Plasma membrane  Some vacuoles but they are usually small and numerous  Cytoplasm throughout the cell  Nucleus may be found anywhere in the cell  Is normally in the center of the cell  Cilia is common in animal cells of higher animals

17. Animal Cell II Cell Specialization Wednesday, October 21, 201517  In animals, cells are often uniquely suited to perform a particular function within the organism  Nerve Cells  Muscle Cells  Rods and Cones in the eye  Sex cells  These specialized cells are determined by complex processes of turning on and off genes.

18. Wednesday, October 21, 201518 Plant Cell

19. Wednesday, October 21, 201519 Animal Cell

20. Plant Cell vs. Animal Cell Similarities  Both Eukaryotic Cells  Have membrane bound organelles Differences  Plant cells are “generally” larger than animal cells  Plant cells have a cell wall of cellulose  Adds stability and protection to the plant cell  Plant cells have vacuoles  That are used as space fillers  Fulfills digestive functions in plants--similar to lysosomes that are also found in animal cells.  Animal cells have centrioles Wednesday, October 21, 201520

21. Review Wednesday, October 21, 201521