The Cell Theory Hairy T-cell

Definition Three part theory about cells 1. All living things are made of cells.

Part 2 of the Theory 2. The cell is the basic structural and functional unit of life.

Part 3 of the Theory 3. All cells come from pre-existing cells. yeast cells dividing

Who came up with this theory? All plants are made of cells! 1. Schleiden (circa 1838) Onion skin cells

Who came up with this theory? 2. Schwann All animals are made of cells! Human red blood cells

Who came up with this theory? 3. Virchow All cells come from pre-existing cells!

How big are cells? Microscopic (mostly) Measured in microns µm = (micrometers) A µm is one millionth of a meter = 10-9 m = one thousandth of 1 mm.

How big are cells? Smallest free-living cell = Mycoplasma genitalium Size = 0.2 to 0.3 µm

How big are cells? Bacteria e.g. Eschericia coli (aka E.coli) Size=1 µm by 3 µm

How big are cells? Human red blood cell = 8 µm in diameter

How big are cells? Largest cell on the human body = ovum Size= 1000 µm in diameter (1 mm)

How big are cells? Smallest cell in the human body = sperm cell. Size= 50 µm in diameter (0.05 mm)

How big are cells? Largest cell with a metabolism = Chaos chaos Size=1-5 mm in length. Common name = Giant Amoeba Chaos diffluens, is an amoeba closely related to the giant amoebae

How big are cells? Largest cell = yolk of an ostrich egg

How can we study cells? Problem: They are microscopic! Solution: Use a microscope!

Types of Microscopes Compound light microscope Light passes through lenses to magnify image up to 1000X Can observe living cells

Types of Microscopes 2. Electron microscope Uses a beam of electrons to magnify image > 1000X Kills cells being observed

Common features of all cells Small size – allows materials to move via diffusion Diffusion = process by which molecules move from levels of high concentration to levels of low concentration until equilibrium is reached

Diffusion

Common features of all cells Cell Membrane – selectively/differentially permeable (lets some things in and out)

Common features of all cells 2. Cytoplasm – semi-fluid material in which cell organelles float

Common features of all cells 3. Nucleic acid containing genetic code : Which nucleic acid? DNA = Deoxyribonucleic Acid

Common features of all cells 4. Cytoskeleton – proteins that support the cell (Microtubules & microfilaments)

Common features of all cells 5. Ribosomes – make proteins

If Cells could be really big …… Star Trek - The Immunity Syndrome

Bibliography http://www.hotlinecancer.com/?cat=28 http://news.bbc.co.uk/1/hi/sci/tech/4636121.stm http://www.thebacteriabusters.com/eColi.html http://www.lungcancer.co.uk/how.htm http://www.fi.edu/learn/heart/blood/red.html http://biology.about.com/library/weekly/aa091400a.htm http://www.pbs.org/wgbh/amex/babies/peopleevents/e_ovum.html http://www.dkimages.com/discover/Home/Animals/Birds/Growth-and-Development/Ostrich/Ostrich/Ostrich-15.html http://www.flickr.com/photos/71751551@N00/1262329163/ http://commons.wikimedia.org/wiki/Image:Ostrich_egg.jpg http://www.mambalam.net/slideshow.php?set_albumName=Animalia http://strangebenevolent.blogspot.com/2007/07/meerkats-and-ostriches.html www.madsci.org/posts/archives/dec97/878139903.Cb.r.html http://en.wikipedia.org/wiki/Amoeba_proteus http://en.wikipedia.org/wiki/The_Immunity_Syndrome_(Star_Trek

Bibliography http://www.pacpress.com/level3/micron.htm Google Image Result for http://www.indiana.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion.gif http://commons.wikimedia.org/wiki/Image:Diffusion.jpg http://library.thinkquest.org/C004535/cell_membranes.html http://sun.menloschool.org/~cweaver/cells/e/ribosomes/ http://www.elmhurst.edu/~chm/vchembook/580DNA.html http://sciencecity.oupchina.com.hk/biology/student/glossary/cytoplasm.asp http://www.uic.edu/classes/bios/bios100/lecturesf04am/lect06.htm