2. CELLS Remember-All living things are made of one or more cells. All the stuff living things do to keep them living is done in the cell!

3. Cell Types- There are two general types of cells- Eukaryotes (“true”) And Prokaryotes (“first”)

4. Let’s start with prokaryotes- Scientists believe the first cells were prokaryotes, or prokaryotic. These cells are simpler than eukaryotes: They don’t have many of the cell parts that we’ll identify. Bacilli Bacteria Bacilli bacteria under magnification. © www.corbis.com/Science Pictures Limited Send as Greeting CardAdd to PageBuilderBuy As a Digital PictureBuy As a Framed Print

5. Prokaryotic cells- Have no “membrane- bound” nucleus They DO have genetic information in a long string of DNA found in the cell Bacteria are prokaryotic cells

6. Eukaryotic cells Have an organized nucleus and membrane-bound organelles Organelles are small specialized parts of eukaryotic cells that have specialized functions

7. Eukaryotic Cells Have different structure for different functions

8. Eukaryotic organelles Nucleus controls cell’s activities and cell reproduction; contains cell’s nucleic DNA Nucleolus inside nucleus produces RNA for ribosomes, is used in cell reproduction

9. …..more organelles- Endoplasmic reticulum (ER) is used for transport within the cell (like a canal system), sometimes contains ribosomes (“rough ER”) Ribosomes are tiny organelles where proteins are assembled (put together from amino acids)

10. …more organelles The “mighty” mitochondrion is where aerobic respiration releases the energy from glucose to produce the ATP molecules that keep our cells doing their jobs All cells need energy to do their jobs. Respiration is the chemical reaction that produces energy. Aerobic respiration uses oxygen.

11. …and more….. Golgi complex (aka “body”, “apparatus”) packages secretions produced by the cell Vacuoles are membrane-bound sacs for storage. Plant cells have a large central vacuole full of “cell sap”, the products of photosynthesis.

12. …and some more…. The plasma (cell) membrane surrounds all cells and regulates what goes into and out of the cell. Cytoplasm is the rest of the cell, a jelly-like substance made mostly of water. Many chemical reactions occur here…and many of those reactions need water.

13. And then, there are some only found in animal cells - Centrioles are found near the nucleus and used for cell reproduction

14. And some only in plant cells - Cell Wall surrounds the cell membrane. It is non-living, made of cellulose, and provides structure (That’s why trees don’t need a skeleton!)

15. Cell walls May be found in organisms other than plants-such as bacteria and fungus, but the composition of the cell wall may be different

16. And green plant cells- Are green because they have chlorophyll in chloroplasts; Within chloroplasts, plants use carbon dioxide and water to produce (synthesize) glucose, so they don’t have to hunt (or shop!) for their food.

17. Other autotrophs- Have chlorophyll also, such as this euglena Prokaryotic autotrophs do not have their chlorophyll contained in membrane-bound chloroplasts

18. And one more organelle- A Lysosome is a sac that contains digestive enzymes; used to break apart food particles in amebas, for example; or used by white blood cells to destroy invaders

19. Variety of Cells Not all cells look alike: their structure(what they look like) will depend on their function (what they do) And not all cells have all the organelles For example, a muscle cell will have many mitochondria because they require a lot of energy Fat cells will have many vacuoles for storage