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Cells

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Erica LaVoi
Erica LaVoi

Cells are the smallest living units that make up all organisms. They come in two main types - single-celled organisms and multi-celled organisms made up of many cells. Cells have a membrane boundary and internal structures called organelles that allow materials to move in and out. Cells are small because as size increases, surface area to volume ratio decreases, making it harder for cells to exchange materials through their membranes as they would need more food but have less surface area for material transport.

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Cells
CellsThe Building Blocks of LifeCell theory- states that cells are the smallest living unit in all organisms and that all cells come from other cells.
Cells: the Basic Building Blocks of LifeSingle Celled Organism- live on their ownMulti Celled Organism- live dependant on other cellsBacteriaRed Blood Cells
PartsMembrane- external boundary of cell that allows materials for life in and outOrganelles- specialized internal structures
Why are cells so small?Volume= how much space does it take up?Surface area= how much ‘skin’ does it have?
Why are cells so small?Calculate the SA and Vol of a sphere that has a radius of 1.5 cm. Calculate the SA and Vol of a sphere that has a radius of 15 cm. SA= 28 cm squared14/28=0.5Vol=14 cm cubedSA= 2800 cm squaredVol=14000 cm cubed14000/2800=5
Why are cells so small?Vol to SA = 8 to 4Vol to SA= 4 to 4
Why are cells so small?Volume is how much room we have- so we can fill all that space with food coming in or waste going out. Surface area is how much room we have to move items in and out. The bigger the cell, the more waste it produces and food it needs, but the less it can move those across the membrane.
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Cells

  • 2. CellsThe Building Blocks of LifeCell theory- states that cells are the smallest living unit in all organisms and that all cells come from other cells.
  • 3. Cells: the Basic Building Blocks of LifeSingle Celled Organism- live on their ownMulti Celled Organism- live dependant on other cellsBacteriaRed Blood Cells
  • 4. PartsMembrane- external boundary of cell that allows materials for life in and outOrganelles- specialized internal structures
  • 5. Why are cells so small?Volume= how much space does it take up?Surface area= how much ‘skin’ does it have?
  • 6. Why are cells so small?Calculate the SA and Vol of a sphere that has a radius of 1.5 cm. Calculate the SA and Vol of a sphere that has a radius of 15 cm. SA= 28 cm squared14/28=0.5Vol=14 cm cubedSA= 2800 cm squaredVol=14000 cm cubed14000/2800=5
  • 7. Why are cells so small?Vol to SA = 8 to 4Vol to SA= 4 to 4
  • 8. Why are cells so small?Volume is how much room we have- so we can fill all that space with food coming in or waste going out. Surface area is how much room we have to move items in and out. The bigger the cell, the more waste it produces and food it needs, but the less it can move those across the membrane.

Editor's Notes

  • #2: Cells- Ch 4
  • #3: Note the legos- legos are made of plastic but being plastic does not mean something is a lego. The picture on the right is a cell dividing.
  • #4: Which cell needs other cells to help it survive? (RBC)
  • #5: Find the membrane. Identify how many different organelles are displayed on this picture.
  • #6: Cells in general are tiny (with the exception of bird eggs). This has to do with some basic math. This diagram gives you the equations to calculate Surface Area and Volume of a sphere.
  • #7: When comparing the surface area to the volume- we see a huge difference as the size gets larger. The bigger the cell, the more volume to surface area.
  • #8: If food can’t get in or wastes can’t get out efficiently, a cell will die. Just like these trucks will back up in the parking lot.
  • #9: (like how many trucks can we fit in a parking lot)(like how many roads to move trucks)
  • #10: We will continue with a worksheet to practice the math and see how size affects a cell.