Cell Theory
Cells are the structural and functional units of life
All plants and animals are made of cells and all cells come from other preexisting cells.
Exceptions to the cell theory are the virus and the fact that the chloroplast and mitochondria have their own DNA.
Plant Cells
Have Cell walls made of cellulose, chloroplasts and a large central vacuole.
Animal Cells
Have centrioles and small vacuoles.
UC CL link to Cell Organelles
3-D drawing of a cell cell wall detailed cell wall
Remember the double lipid layer of the selectively permeable cell membrane.
Diffusion across the cell membrane tries to equal the concentration inside and outside the cell. (Trying to maintain Homeostatsis)
It does not require energy. Imagine riding a bike downhill. It requires very little effort on your part. This explains how water enters the roots of a plant after a rain. A lot of water outside the root and it moves into the plant. animation of diffusion Active transport is the movement of material from a low to a high concentration. This does require energy. (ATP) This is like riding a bike uphill. It requires a great deal of effort. This is how a plant gets rid of a toxin if there is more in the soil than in it’s roots. The plant “pumps” it out “against the tide”. This is because there is more toxin outside the plant than inside the plant.

Open Ended Question
1. Do organisms and automobiles both carry on similar life functions?
2. Is a car alive? Why or Why not?
3. State three parts of the cell theory.