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?

1. Schleiden (circa 1838) All plants are made of cells!

Onion skin cells

2. Schwann

Who came up with this theory?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.

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

Ostrich, egg, humans

Ostrich emerged from egg

How can we study cells?

Problem:They are microscopic!

Solution:Use a microscope!

Types of Microscopes

1. 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 cellsSmall 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• Google Image Result for http://www.indian

a.edu/~phys215/lecture/lecnotes/lecgraphics/diffusion.gif

Common features of all cells

1. 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

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