1. Cell Organelles Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics. –Cells tend to be microscopic. –All cells are enclosed by a membrane. –All cells are filled with cytoplasm. –All cells have DNA. Bacterium (colored SEM; magnification 8800x) cell membrane cytoplasm

2. Cell Organelles There are two cell types: eukaryotic cells and prokaryotic cells. Eukaryotic cells have a nucleus. Eukaryotic cells have membrane- bound organelles. nucleus cell membrane organelles

3. Cell Organelles There are two cell types: eukaryotic cells and prokaryotic cells. Prokaryotic cells do not have a nucleus. Prokaryotic cells do not have membrane- bound organelles. nucleus cell membrane organelles cytoplasm

4. Cell Organelles Why do cells have different shapes?

5. Cell Organelles KEY CONCEPT Eukaryotic cells share many similarities.

6. Cell Organelles Cells have an internal structure. The cytoskeleton has many functions. – –supports and shapes cell – –transports organelles – –provides strength – –assists in cell division

7. Cell Organelles A B C D Click to animate the image. The cytoskeleton helps the cell move, keep its shape, and organize its parts.

8. Cell Organelles Several organelles are involved in making and processing proteins. The nucleus stores genetic information.

9. Cell Organelles The Nucleus A B C D The nucleolus produces ribosomes.

10. Cell Organelles Several organelles are involved in making and processing proteins. Many processes occur in the endoplasmic reticulum.

11. Cell Organelles Several organelles are involved in making and processing proteins. There are two types of endoplasmic reticulum.

12. Cell Organelles Several organelles are involved in making and processing proteins. The nucleus stores genetic information. Many processes occur in the endoplasmic reticulum. There are two types of endoplasmic reticulum. – –rough endoplasmic reticulum – –smooth endoplasmic reticulum

13. Cell Organelles Rough ER has ribosomes and takes part in the production of protein Smooth ER lacks ribosomes. Smooth ER makes lipids and breaks down drugs and alcohol.

14. Cell Organelles Ribosomes link amino acids to form proteins.

15. Cell Organelles Golgi apparatus is a set of flattened, membrane-bound sacs that helps modify and package proteins for release from the cell.

16. Cell Organelles Vesicles are membrane-bound sacs that hold materials. Vesicles store and release a variety of substances as the cell needs them.

17. Cell Organelles

18. Other organelles have various functions. Mitochondria supply energy to the cell.

19. Cell Organelles Other organelles have various functions. Vacuoles are fluid-filled sacs that hold materials.

20. Cell Organelles Other organelles have various functions. Lysosomes contain enzymes to digest material.

21. Cell Organelles Other organelles have various functions. Centrioles help divide DNA and form cilia and flagella

22. Cell Organelles Plant cells have cell walls and chloroplasts. A cell wall provides rigid support.

23. Cell Organelles Plant cells have cell walls and chloroplasts. Chloroplasts convert solar energy to chemical energy. (photosynthesis)