Cell Features

1
Cell Features
http//personal.tmlp.com/Jimr57/textbook/chapter3/
images/cell1.jpg
http//www.rds-online.org.uk/upload/images/left/ad
ult20human20bone20marrow20stem20cell.jpg
http//biology.clc.uc.edu/graphics/taxonomy/plants
/spermatophyta/angiosperms/dicotyledonae/Rutaceae/
Gas20Plant/JSC20000520Gas20Plant.JPG
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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.

3
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 dont need to travel as far to reach
  the center of a small cell.

4
http//ghs.gresham.k12.or.us/science/ps/sci/soph/c
ells/pics/surfvol.jpg

• 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//library.thinkquest.org/C006669/media/Biol/i
mg/surface_area_to_volume_ratio.gif
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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

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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/Bi
oGallery00/presentation.llem/EM/SEM203D20photo2
0of20E-Coli2023A93.jpg
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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/document
s/gifs/eukaryote.gif
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Eukaryotic Cells
Paramecium
http//web.ukonline.co.uk/m.hoult/fw/images/amoeba
.jpg
http//www.pirx.com/droplet/gallery/paramecium/par
amecium1.jpg
Plant Cell
White Blood Cell and Bacteria ( a prokaryote)
http//images.google.com/images?svnum10hlenlr
qwhitebloodcellbtnGSearch
http//www.biologie.uni-hamburg.de/b-online/fo04/2
vergrzw.jpg
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Cell Membrane

• Lipid bilayer
• Selectively permeable

http//library.thinkquest.org/C004535/media/cell_m
embrane.gif
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Homework

• Read Chapter 3 Section 2 55-60
• Answer Questions 1-5