1. CHAPTER 7-2 Eukaryotic Cell Structure

2. Basic Cell Info Cells are like factories  Every part inside the cell has a specific job Each part of a cell functions like a little organ  Little organ = Organelle Cells are divided into 2 parts  Nucleus  Cytoplasm Cytoplasm is the jelly-like interior PLUS all the organelles outside the nucleus

3. Eukaryotic Cell Organelles Plant and Animal:  Cell membrane  Nucleus  Nucleolus  Nuclear envelope  Ribosomes  Rough Endoplasmic Reticulum  Smooth Endoplasmic Reticulum  Golgi Bodies (Apparatus)  Lysosomes  Mitochondria  Vacuoles  Cytoskeleton Animal Cells:  Centrioles  Many small vacuoles Plant Cells:  Cell walls  Chloroplasts  One central water Vacuole

4. Eukaryotic Animal Cell

5. Eukaryotic Plant Cell

6. Nucleus Nucleus: control center of the cell houses chromatin DNA bound to Proteins Code for proteins and molecules) Nuclear Envelope: a porous membrane that surrounds the nucleus Protects DNA from damage Allows only specific molecules in or out Nucleolus : A special, dense location inside the nucleus Site of ribosome formation

7. Ribosomes Protein Machines Made of ribosomal RNA (rRNA) and protein Found free floating and attached to Rough Endoplasmic Reticulum Attaches amino acids (Protein monomers) together into a chain (polypeptide)  Uses messenger RNA (mRNA) and transfer RNA (tRNA)

8. Rough Endoplasmic Reticulum An extensive network of membrane-bound tubules surrounding the nucleus Shapes proteins as they are being formed by ribosomes  The attached ribosomes “feed” the forming protein into the RER through pores Called “Rough” ER because of the rough appearance ribosomes give it under a microscope

9. Smooth Endoplasmic Reticulum An extension of RER Does NOT have ribosomes covering it Helps make fats (lipids) and cholesterols  This is where components of the cell membrane are initially formed as well as membranes for other organelles

10. Golgi Bodies (Apparatus) Look like stacks of flattened pancakes Made of pinched-off pieces of RER containing folded/shaped proteins Packaging/Shipping department of cell  Similar to a post office, this organelle sends the proteins to their final destination (either cell membrane or out of the cell)

11. Lysosomes Janitors of the cell Contain lots of enzymes and have a pH of about 5 (acidic) Break down old organelles and metabolic wastes before they harm the cell

12. Vacuoles Storage Closets of cell Store food, water, waste Plant cells have one large, central water vacuole  Allows the plant to support heavy structures such as leaves Animal cells can have many small vacuoles for food and water Some single-celled organisms have special vacuoles called contractile vacuoles  These pump out excess water by contracting in order to maintain homeostasis Plant Cell: Central Vacuole

13. Mitochondria Powerhouse of the cell Double-membrane organelle Creates energy in the form of adenosine triphosphate (ATP) Site of Aerobic Respiration!  In other words, this is where sugar is broken down with oxygen to make energy (ATP) Cells that need LOTS of energy have LOTS of mitochondria  EX: muscle cells, brain cells Has its own DNA

14. Plant Cell Exclusive: Chloroplast Double-membrane organelles Site of photosynthesis Contain the green pigment chlorophyll (a protein) Builds sugar (glucose) molecules from Water, Co 2, in the presence of sunlight Has its own DNA

15. Cytoskeleton Internal network of protein filaments and tubules Provide:  Shape and support  Pathways for molecules and organelles to move  Ex: Golgi bodies send proteins out along microtubules  Movement of cell parts  Ex: cilia, microvilli, flagella

16. Animal Cell Exclusive: Centrioles Aide in cell division Made of microtubules Form spindle fibers and astral rays during mitosis and meiosis  (More to come in chapters 10 and 11)

17. Cell Membrane The bouncer Decides what goes in and out of the cell Controls cellular transport based on molecule size AND special transport proteins that are specific for moving certain molecules across the membrane Made MOSTLY of lipids, contains SOME proteins

18. Plant Cell Exclusive: Cell Wall Give the plant cell rigidity and support Made of cellulose  Plant starch Prevents the plant cell from exploding when water pressure (osmotic pressure) is too high in the cell

19. Important Points! Plant and animal cells are Eukaryotic! Prokaryotic cells contain SOME but not all of the structures reviewed in this power point Bacteria (Prokaryotes) have NO nucleus, but they MIGHT have a cell wall Fungi (Eukaryotes) have NO chloroplast, but do have a nucleus and cell wall  Fungi are NOT plants!