1. Chapter 4: Cell Organization  Pgs 74-105

2. Student Objectives  Summarize the relationship among cell organization, cell size and maintaining homeostasis.  Discuss microscopy used to study cells  Compare and contrast general characteristics of prokaryotic and eukaryotic cells  Summarize the relationship among cell organization, cell size and maintaining homeostasis.  Discuss microscopy used to study cells  Compare and contrast general characteristics of prokaryotic and eukaryotic cells

3. Student Objectives  Distinguish among the different organelles of a cell.  Describe the structure and function of the cytoskeleton.  Compare and contrast cilia and flagella.  Distinguish among the different organelles of a cell.  Describe the structure and function of the cytoskeleton.  Compare and contrast cilia and flagella.

4. Cell Theory  Cells are the basic units of organization and function. (No isolated part of the cell is capable of survival)  Cells come from other existing cells  All living things are made up of cells. (They are the building blocks of complex organisms)  Cells are the basic units of organization and function. (No isolated part of the cell is capable of survival)  Cells come from other existing cells  All living things are made up of cells. (They are the building blocks of complex organisms)

5. Cells Three main parts: Plasma membrane (cell membrane) - selectively permeable Cytoplasm: Fluid and organelles outside of the nucleus. (cytosol-fluid) Nucleus - Control center of the cell. Eukaryotic cells Three main parts: Plasma membrane (cell membrane) - selectively permeable Cytoplasm: Fluid and organelles outside of the nucleus. (cytosol-fluid) Nucleus - Control center of the cell. Eukaryotic cells

6. Cell Size  Cells are microscopic  Measured in micrometers (µm)  Cells organelles are measured in nanometers (nm) - 1/1000 of a micrometer  Cell size limited by its surface area to volume ratio *Some cells can be seen without a microscope. (Eggs) human egg cell is 130 µm.  Cells are microscopic  Measured in micrometers (µm)  Cells organelles are measured in nanometers (nm) - 1/1000 of a micrometer  Cell size limited by its surface area to volume ratio *Some cells can be seen without a microscope. (Eggs) human egg cell is 130 µm.

7. Cell Beginnings First studied and documentated in 1665 by Robert Hooke. He examined ‘cork’ cells. (dead wood) Anton van Leeuwenhoek - later looked at cells at up to 200 times mag. First studied and documentated in 1665 by Robert Hooke. He examined ‘cork’ cells. (dead wood) Anton van Leeuwenhoek - later looked at cells at up to 200 times mag.

8. Microscopes Allowed scientists to see microscopic things.  Light Microscope. Simple - 1 lens Compound - 2 lens (ocular and objective) Magnify from 40 to 1000 Bright field or dark field microscopy Allowed scientists to see microscopic things.  Light Microscope. Simple - 1 lens Compound - 2 lens (ocular and objective) Magnify from 40 to 1000 Bright field or dark field microscopy

9. Microscopes Electron Microscopes (EM) Began in 1950’s Can magnify up to 250,000 times Transmission electron Microscope (TEM) -Specimen is embedded in plastic and cut into thin sections Scanning Electron Microscope (SEM) -Electrons strike the surface of the specimen. Electron Microscopes (EM) Began in 1950’s Can magnify up to 250,000 times Transmission electron Microscope (TEM) -Specimen is embedded in plastic and cut into thin sections Scanning Electron Microscope (SEM) -Electrons strike the surface of the specimen.

10. Electron Microscope

11. Cell Parts  Nucleus  Large organelle (5 µm) usually near the center of the cell. ‘Control Center’ - Contains chromosomes  Nuclear membrane contains the nucleoplasm.  Material is transported between nucleoplasm and cytoplasm through nuclear pores.  Nucleus  Large organelle (5 µm) usually near the center of the cell. ‘Control Center’ - Contains chromosomes  Nuclear membrane contains the nucleoplasm.  Material is transported between nucleoplasm and cytoplasm through nuclear pores.

12. Cytoplasmic Organelles  Endoplasmic reticulum (ER) - complex compartments of the cell. Contain enzymes ‘catalysts’  Two Types  Smooth ER - no ribosomes - site of lipid metabolism  Rough ER - ribosomes - site of protein synthesis  Endoplasmic reticulum (ER) - complex compartments of the cell. Contain enzymes ‘catalysts’  Two Types  Smooth ER - no ribosomes - site of lipid metabolism  Rough ER - ribosomes - site of protein synthesis

13. Cytoplasmic Organelles  Ribosomes  Site of protein synthesis. Works closely with ER and RNA  Ribosomes  Site of protein synthesis. Works closely with ER and RNA

14. Cytoplasmic Organelles  Golgi Complex  Similar to ER except the stacks of flattened membranous sacs are not continuous  Processes proteins and complex sugars  Golgi Complex  Similar to ER except the stacks of flattened membranous sacs are not continuous  Processes proteins and complex sugars

15. Cytoplasmic Organelles  Lysosomes  Small sacs of digestive enzymes. Slightly acidic  Break down worn out organelles, digest bacteria or other debris  Lysosomes  Small sacs of digestive enzymes. Slightly acidic  Break down worn out organelles, digest bacteria or other debris

16. Cytoplasmic Organelles  Peroxisomes  Contain enzymes that catalyze the split of hydrogen peroxide H 2 0 2 which is toxic to the cell.  Peroxisomes  Contain enzymes that catalyze the split of hydrogen peroxide H 2 0 2 which is toxic to the cell.

17. Cytoplasmic Organelles  Vacuoles  Found mainly in plant cells, does the same job as lysosomes.  As the vacuole grows with the addition of water the size of the cell grows.  May be up to 90% of a plant cell volume.  Some vacuoles are specialized  Food vacuoles - digest foods  Contractile vacuoles - remove excess water  Vacuoles  Found mainly in plant cells, does the same job as lysosomes.  As the vacuole grows with the addition of water the size of the cell grows.  May be up to 90% of a plant cell volume.  Some vacuoles are specialized  Food vacuoles - digest foods  Contractile vacuoles - remove excess water

18. Cytoplasmic Organelles  Mitochondria - ‘powerhouse’  Site of aerobic respiration - conversion of chemical energy to ATP  Most numerous in cells requiring high energy  Mitochondria - ‘powerhouse’  Site of aerobic respiration - conversion of chemical energy to ATP  Most numerous in cells requiring high energy

19. Cytoplasmic Organelles  Chloroplasts - similar to mitochondria  Found only in algae and plants cells  Convert light energy into chemical energy  Contains chlorophyll, the green pigment that traps light (photosynthesis).  Chloroplasts - similar to mitochondria  Found only in algae and plants cells  Convert light energy into chemical energy  Contains chlorophyll, the green pigment that traps light (photosynthesis).

20. Cytoskeleton  Give the cell its shape  Dense network of protein fibers  Microtubules - thickest filaments of the cytoskeleton (25 nm)  Microfilaments - flexible solid fibers (7 nm)  Give the cell its shape  Dense network of protein fibers  Microtubules - thickest filaments of the cytoskeleton (25 nm)  Microfilaments - flexible solid fibers (7 nm)

21. Centrosome  Cell division center  Contains two centrioles (found in animal cells but not plants)  Centrioles move to the ‘poles’  Cell division center  Contains two centrioles (found in animal cells but not plants)  Centrioles move to the ‘poles’

22. Spindle Fibers  Serve as a framework and attachment for chromosomes for the seperation to the opposite ‘poles’

23. Cell Coverings  Glycocalyx (cell coat)  Formed by carbohydrates, proteins and lipids on the plasma membrane.  Form adhesives for neighboring cells and help in cell signaling  Plant cells have Cell Walls - made of cellulose  Glycocalyx (cell coat)  Formed by carbohydrates, proteins and lipids on the plasma membrane.  Form adhesives for neighboring cells and help in cell signaling  Plant cells have Cell Walls - made of cellulose

24. Cilia and Flagella  Made up of microtubes, aid in movement of the cell  Flagella are long compared to the cell (200 µm)  Cilia are short (2-10 µm), usually many  Made up of microtubes, aid in movement of the cell  Flagella are long compared to the cell (200 µm)  Cilia are short (2-10 µm), usually many