1. The Cell Theory

2. Modern Cell Theory
All living things are composed of one or more cells.
The cell is the functional unit of life
All cells come from preexisting cells

3. Comparing Cells
The size & shape of a cell relates to its function. (job it does)

4. From Cell To Organism Tissue Group of cells working together
Group of tissues working together
Organ System
Group of organs working together
Organism
Any living thing made of 1 or more cells

5. Cell Division All cells come from preexisting cells
Life is not “spontaneously” generated (i.e. created from non-living parts.)
Key functions for life:
Healing and tissue repair
Growth of an organism
Reproduction of organisms

6. Two Kinds Of Cells cells without membrane-bound structures
Prokaryotic Cells (proh KAYR ee yah tihk)
cells without membrane-bound structures
EX: bacteria, pond scum
Eukaryotic Cells (yew KAYR ee yah tihk)
cells with membrane-bound structures
EX: animals, plants, fungi and protists
Our focus will be Eukaryotic Cells

7. Common Cell Parts Cell Membrane Nucleus Outer protective covering
Allows food and water in
Allows waste products out
Nucleus
Directs all cell activities
Separated from cytoplasm by nuclear membrane
Cytoplasm
gelatin-like protoplasm
inside cell membrane
constantly flows
Nucleolus
Makes proteins
Chromatin
contains genetic code that controls cell
made of DNA & proteins
Cytoskeleton
scaffolding-like structure in cytoplasm
gives the cell its shape
made of protein
Organelles
specialized structures within the cell

8. Lesson #2

9. Q: Why are humans made of many cells?
Think about:
Growth and healing (size)
Hunting and food gathering (mobility)
Adapting to different environments (resiliency)

10. Q: Are single celled organisms alive?
Think about:
What defines life

11. Q: Is a single human cell alive?
Think about:
Blood cell
Skin cell
Fertilized egg

12. Common Misconceptions
Misconception: All animal cells are circular and all plant cells are rectangular.
Cells differ widely in terms of shape.
Misconception: All animal and/or plant cells are identical in terms of structure. For example, all cells contain a nucleus.
Red blood cells are enucleated.
Misconception: Cells contain only the genetic material that they use. For instance, a skin cell has DNA only for the functioning of that skin cell.
All cells contain the DNA of the whole genome yet express only the genes that are crucial to their functioning.

13. Plant & Animal Cell Differences
Cell Wall
Only plants have a cell wall
Provides the “woody” regular structure
Chloroplasts
Only plants have chloroplasts for photosynthesis
Mitrocondria
Animals have more mitrocondria for energy conversion
Vacuoles
Plants have bigger vacoules