Cell Theory, Surface Area to Volume Ratio, and Cell Types.

1
Cell Theory, Surface Area to Volume Ratio, and
Cell Types.

• AP Biology
• 10/25/06

2
The Cell Theory

• All living things are made of cells, and all
  cells come from other cells

3
Cells in Organisms

• Unicellular Organisms living things that have
  only one cell
• Bacteria
• Some protists
• Some fungi and plants
• Multicellular Organisms living things that have
  many cells
• most plants and animals

4
Cell Size

• Most plant and animal cells are between 10 and
  100 mm in diameter.
• (1 mm is a micrometer, or micron, and is 1
  millionth of a meter)
• See page 54 for cell sizes.

5
Why are cells so small?

• Surface Area to Volume Ratio
• A cell needs a big enough membrane to serve all
  its transport needs.
• Many small cells have a much greater combined
  surface area (membrane area) compared to their
  combined volume than one very big cell of the
  same total volume.
• Page 54

6
Cell Types
Prokaryotes Eukaryotes
Bacteria and archaebacteria Plants, animals, protists, and fungi
Differences Smaller No internal membranes Have nucleoids Some have cell capsules Larger have internal membrane-bound organelles Have nuclei No capsules
similarities all have plasma membranes and ribosomes Some have cell walls and/or flagella all have plasma membranes and ribosomes Some have cell walls and/or flagella
7
Prokaryote vs. Eukaryote
8
Eukaryotes Plant vs. Animal Cells (pp 56-57)
Animal Cells Plant Cells
Unique Organelles Flagellum Lysosome Centriole Central Vacuole Choroplast Cell wall
Both have Cell membrane, nucleus, rough endoplasmic reticulum (ER), smooth ER, Golgi Apparatus, Cytoskeleton, Mitochondrion, Peroxisome, ribosomes Cell membrane, nucleus, rough endoplasmic reticulum (ER), smooth ER, Golgi Apparatus, Cytoskeleton, Mitochondrion, Peroxisome, ribosomes
9
Eukaryotes Plant vs. Animal Cells (pp 56-57)