1. The Cell

2. First view of cells: Robert Hooke

3. Antony Van Leeuwenhook
One of the fathers of microbiology
Built light microscopes
Discovered bacteria, unicellular protists, and more

4. Cell Theory All living things are made of cells
Cells are the basic unit of life
All cells come from preexisting cells
Formed by Schlieden, Schwann, and Virchow
Germany, 1839

5. Cytology and Histology
Cytology: The study of CELLS!
Histology: The study of TISSUES!

6. Microscopes Light (compound and dissection)
Electron (scanning and transmission)
Electron Tomography
Confocal

7. Microscopes Light microscope- resolves to about .2 um
magnification
Electron microscope- resolves to about .2 nm
Scanning (SEM)-cell surfaces
Transmission(TEM)-Internal contents
**what is the disdavantage?
(note the newer STM, scanning tunneling, enables 3-D images and can be used w/ living)

8. Which microscope to use?

9. Why are cells so small? What’s keeping them from being larger?
Cells vary in size from about 1 um (bacteria) to about 1m (sciatic neuron-nerve cell)

10. Surface Area to Volume Ratio
Cells must divide when volume exceeds surface area

11. Prokaryotic Cells Lack membrane bound nucleus
And membrane-bound organelles
DNA found in nucleoid region
Like many eukaryotic cells, these cells have cell walls, plasma membranes, flagella and ribosomes
Unlike eukaryotic cells, they may have a capsule and pili

12. Eukaryotic Cells

13. Meet the Organelles

14. Nucleus “Brain” of the cell Contains the hereditary information of DNA
Controls all functioning of the cell
Contains the hereditary information of DNA
DNA = coded instructions for making proteins and other important molecules
Packaged as chromatin
Chromatin = DNA bound to protein
Nucleus is important because making proteins is one of the main functions of the cell

15. Nucleolus Dark regions within the nucleus produces ribosomes
In animal & plant cells

16. Ribosomes
Organelle that carries out protein synthesis/interprets code from RNA. Made of rRNA and protein
Can be attached to ER or floating
In plants & animal cells

17. Cell Wall Outside the cell membrane
Found in all cells except animal cells
Made from carbohydrates
Cellulose – plants
Chitin – fungi
Peptidoglycan – bacteria
Provides support, protection and excessive uptake of H2O

18. Cellulose v. Chitin v. Peptidoglycan

19. Cell Membrane Thin flexible barrier around the cell
Selectively permeable
Made of:
phospholipid bilayer / proteins / carbohydrate chains /cholesterol

20. Endoplasmic Reticulum
Membranous maze connected to nuclear envelope
Rough ER – Covered in ribosomes
Makes proteins and cell membrane
Smooth ER – no ribosomes present
Lipid synthesis
Detoxifies harmful substances
Cells in liver have a lot of smooth ER

21. Golgi Apparatus
Center of manufacturing, processing, packaging and shipping
Enzymes here attach carbohydrates and lipids to proteins
After the ER makes the proteins, they move into the Golgi Apparatus where they are modified
From the Golgi Apparatus , modified proteins are moved to their destinations

22. Lysosomes
Small organelle filled with hydrolytic enzymes that cell uses to digest macromolecules. Important in phagocytosis
Debris removal of worn out organelles
Acidic interior (pH-5)

23. Vacuoles Membrane bound sacs
Temporary storage areas for food water, enzymes and waste
Special types
Contactile: pumps out excess water in single celled water dwelling organisms
ex-aquatic protists, such as protozoans
Central: large vacuole found in plants used for water storage

24. Mitochondria 6O2 + C6H12O6  6CO2 + 6H20 +Energy
Conducts Cellular Respiration: releases energy from stored food molecules
ATP is made here
Energy released from the mitochondria is used by the cell for growth, development and movement
6O2 + C6H12O6  6CO2 + 6H20 +Energy

25. Chloroplasts Light energy + 6H2O + 6CO2 ----- C6H12O6 + 6O2
Use energy from sunlight to make energy- rich food molecules in a process known as photosynthesis
Found in autotrophic cells
Shaped like lenses
Double membrane
Light energy + 6H2O + 6CO  C6H12O6 + 6O2

26. Centrioles
Organelles made of microtubules and are involved in cell division
Two centrioles are usually found together in a structure called the centrosome
Animal cells only

27. Peroxisomes Specialized compartment bound by single membrane
Similar to lysosomes (contains enzymes)
Generation and degradation of H2O2 (hydrogen peroxide) to protect cell from it’s toxic effects

28. Cytoskeleton Microfilaments Intermediate fibers Microtubules
Thinnest, made of protein, help cells change shape
Intermediate fibers
Varied, rope-like, tension bearing
Microtubules
Largest, anchorage and movement

29. Cilia and Flagella Extensions of plasma membrane Cytoskeletal elements
Both have 9+2 microtubule arrangement
Identical in structure to centriole

30. Cytoplasm
Everything between the plasma membrane and the nuclear envelope
Semifluid (cytosol) with organelles suspended in it
Protoplasm=cytoplasm+nucleoplasm (inside nucleus)

31. Cell Junctions Animal cells See Handout and/or book Plant cells
Plasmodesmata- junctions between plant cells (walls)
Animal cells
Tight junctions
Anchoring junctions (desmosomes)
Communicating (Gap)

32. Meet the Organelles