Cell Featureshttp://personal.tmlp.com/Jimr57/textbook/chapter3/images/cell1.jpg

http://biology.clc.uc.edu/graphics/taxonomy/plants/spermatophyta/angiosperms/dicotyledonae/Rutaceae/Gas%20Plant/JSC%200005%20Gas%20Plant.JPG

http://www.rds-online.org.uk/upload/images/left/adult%20human%20bone%20marrow%20stem%20cell.jpg

Cell Theory

• 1. All living things are made of one or more cells.

• 2. Cells are the basic unit of structure and function in organisms.

• 3. All cells arise from existing cells.

Small cells function more efficiently than large cells

• Small cells can exchange substances more rapidly than large cells because small objects have a higher surface area to volume ratio.

• Substances don’t need to travel as far to reach the center of a small cell.

• Cells must be small as larger cells find it difficult to bring in enough food, and export enough wastes to keep the cell alive.

• As cell size increases, the ratio of cell volume to cell surface area decreases. At some point as cells increase in size, there isn't enough cell membrane to adequately supply the cell interior with enough oxygen, water, and food. When this happens, the cell dies.

http://ghs.gresham.k12.or.us/science/ps/sci/soph/cells/pics/surfvol.jpg

http://library.thinkquest.org/C006669/media/Biol/img/surface_area_to_volume_ratio.gif

Common features of cells

• Cell membrane – encloses the cell, regulates what enters and leaves the cell

• Cytoplasm- interior of a cell

• Cytoskeleton- system of microscopic fibers

• Ribosomes-make proteins

• DNA-instructions for making proteins, regulates cellular activities and reproduction

Prokaryotes

• Smallest and simplest• Single-celled

organism that lacks a nucleus and other organelles.

• Bacteria– Cell wall –provides

structure and support– Flagella- long

threadlike structures used for movement

http://www.prokaryote.com/prokaryote.jpg

http://www.haverford.edu/biology/Courses/bio300/BioGallery00/presentation.llem/EM/SEM%203D%20photo%20of%20E-Coli%20%23A93.jpg

Eukaryotic Cells

• Has a nucleus and membrane bound organelles

• Organelle- structure that carries out specific activities in the cell.

• Cilia and flagella move some cells through their environment.– Cilia-short hairlike

structures

http://bioweb.usc.edu/courses/2001-spring/documents/gifs/eukaryote.gif

Eukaryotic Cells

http://www.pirx.com/droplet/gallery/paramecium/paramecium1.jpg

http://web.ukonline.co.uk/m.hoult/fw/images/amoeba.jpg

http://images.google.com/images?svnum=10&hl=en&lr=&q=white+blood+cell&btnG=Search

Paramecium

White Blood Cell and Bacteria ( a prokaryote)

Plant Cell

http://www.biologie.uni-hamburg.de/b-online/fo04/2vergrzw.jpg

Cell Membrane

• Lipid bilayer• Selectively permeable

http://library.thinkquest.org/C004535/media/cell_membrane.gif

Homework

• Read Chapter 3 Section 2 55-60

Answer Questions 1-5