1. Cells & The Cell Theory

3. Characteristics of Cells

4. History of the Cell

5. The Cell Theory
All living things are composed of cells or cell fragments.
All cells come from previously existing cells.

6. Cells
Cells are organized into two groups.
Prokaryotic
Eukaryotic

7. Prokaryotic and eukaryotic cells differ in size and complexity
All cells are surrounded by a plasma membrane.
The semifluid substance within the membrane is the cytosol, containing the organelles.
All cells contain chromosomes which have genes in the form of DNA.
All cells also have ribosomes, tiny organelles that make proteins using the instructions contained in genes.

8. A major difference between prokaryotic and eukaryotic cells is the location of chromosomes.
In an eukaryotic cell, chromosomes are contained in a membrane-enclosed organelle, the nucleus.
In a prokaryotic cell, the DNA is concentrated in the nucleoid without a membrane separating it from the rest of the cell.

9. Fig The prokaryotic cell is much simpler in structure, lacking a nucleus and the other membrane-enclosed organelles of the eukaryotic cell.

10. Cellular Structures (Organelles)

11. Cell Membrane The outer covering of the cell.
Regulates movement of materials into and out of the cell.

12. Nucleus The “brain” of the cell
Controls all of the functions of the cell.

13. Mitochondria
The chemical processes that provides energy for the cell take place within the mitochondria.

14. Vacuoles
Storage sacks for cellular material and water.

15. Ribosomes
Make protein that will be used by the cell.

16. Cell Wall Found only in plant cells
the outer/protective covering of the cell.
Provides support and shape for the cell.

17. Chloroplasts Site of photosynthesis
Uses light and water to produce food molecules for the cell.

18. Endoplasmic Reticulum
Helps movement of materials within the cell.
Alters proteins made by the ribosomes.

19. Golgi Apparatus Changes protein molecules as needed by the cell.
Stores and secretes chemicals for the cell.

20. Lysosomes Usually found in animal cells.
Rids the cell of unwanted or defective parts.
Stores digestive enzymes.

21. Comparing Plant Cells to Animal Cells
How do plant cells differ from animal cells?

22. Fig. 7.7
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

23. Fig. 7.8
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings