1. Chapter 4- A View of the Cell

2. 4.1-The Discovery of Cells
Cells are the basic units of living organisms
Development of the microscope allowed scientists to view cells

3. Cell Theory 1665-Robert Hooke Uses compound microscope to observe cork
Hollow boxes…..CELLS!!
1830s-Schleiden and Schwann
Schleiden-all plants are composed of cells!
Schwann-all animals are composed of cells!

4. Three Parts of Cell Theory
1. All organisms composed of one or more cells.
2. Cell is the basic unit of organization of organisms.
3. All cells come from preexisting cells.

5. History of the Microscope
1665-Hooke’s Microscope
Three lenses
Poor Quality
Little detail

6. 1700-Anton van Leeuwenhoek
Built over 240 microscopes!
Single Lens
Better Quality
Observed red blood cells & bacteria
Mid 1800s-Compound Light Microscope
Series of lenses
Light passes through object then lens
More detail

7. 1940s-Electron Microscopes
Beam of electrons through magnetic field
Specimen in vacuum
Only view dead cells or organisms
1.SEM-Scanning Electron Microscope
Surface of specimen-3D Picture!
2.TEM-Transmission Electron Microscope
Through the specimen
Magnify 100s or 1,000s of times!
3.STM-Scanning Tunneling Microscope
Arrangement of atoms on surface
Map hills and valleys

8. Basic Cell Types… Look at internal organization!
Prokaryotes-lacks internal structures
Eukaryotes-membrane bound, internal structures.
Structures called organelles
Largest organelle = NUCLEUS!

11. Section 4.2-Eukaryotic Cell Structure
Must have boundaries!
Plasma Membrane
Boundary between cell & environment
Flexibility
Controls movement of materials
Cell Wall-only plant cells!
Rigid, surrounds membrane
Thicker, stronger network for structural support

12. Fluid-Mosaic Membrane

13. GET UNDER CONTROL!!!!
Nucleus-contains cell’s DNA, manages cell function
Surrounded by nuclear envelope
Double membrane-pores allow movement
Chromatin-long strands of DNA
Packed into chromosomes

14. Nucleus

15. Nucleolus
Region inside nucleus
Produces particles for protein synthesis
Particles are called ribosomes
Cell assembles enzymes according to DNA
Not bound by membrane

16. Nucleolus

17. Assembly, Transport, & Storage
Cytoplasm-outside nucleus, surrounds organelles
Clear liquid
Important chemical reactions (protein assembly) take place here
Endoplasmic Reticulum (ER)-
Network of interconnected compartments
Surface folded into cell
Tissues in a box!
Site for lipid synthesis in cell

18. Smooth or Rough? Smooth ER Rough ER ER acts as cell’s delivery system!
Lacks ribosomes on surface
Rough ER
Studded with ribosomes on surface
ER acts as cell’s delivery system!

20. Structures for Storage
Golgi Apparatus
Closely stacked, flattened membrane sacs
Receives proteins and lipids
Modifies them chemically, repackages
Distributes them throughout membrane
Vacuole-sac of fluid
Temporary storage of food, enzymes etc.
Animal cell-small and numerous
Plant cell-single large vacuole for water

21. Golgi Apparatus
Vacuole

22. Reduce, Reuse, RECYCLE! Lysosomes
Digest excess or worn out cell parts, food particles, and invading viruses/bacteria
Membrane protects digestive enzymes from rest of cell

23. Energy Transformers Mitochondria Break down food-convert to energy!
Peanut-shaped
Highly folded inner membrane for more energy storage
Chloroplasts-plants only!
Transform light energy into chemical energy
Chlorophyll-traps energy from sun
Green color!

24. NRG!!

25. Support and Locomotion
Cytoplasm
1. Cytoskeleton-network of fibrous elements
Act as scaffold for organelle support
2. Microtubules-thin, hollow cylinders
Made of protein
3. Microfilaments-thin, solid fibers
Both make up most of cytoskeleton

26. LET’S GET MOVING! Cilia Flagella Short, numerous hair-like projections
On cell’s surface
Movement like “the wave!”
Flagella
Longer projections
Whip-like motion
One or two per cell

27. Flagella vs Cilia

28. Cellular Organization
1. Single-celled organisms: Unicellular
2. Many-celled organisms: Multicellular
3. Cells functioning together for activity: Tissues
4. Two or more tissues functioning together: Organs
5. Organs working together to carry out major life functions:Organ System