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Chapter 7 Cell Structure http://content.answers.com/main/content/wp/en-commons/thumb/7/70/300px-FluorescentCells.jpg Chapter 7 Vocabulary 1. Cell wall-Strong supportive layer found on the outside of the cell membrane. 2. Cell membrane- Thin flexible layer surrounding the cell; controls what enters or leaves the cell. 3. Chloroplasts-Organelle found in plant cells that capture energy from sunlight and converts it into chemical energy. 4. Eukaryote-a cell with a nucleus and organelles. Vocab 5. Ribosome—Organelle that makes protein 6.Mitochondrion-powerhouse of the cell; converts chemical energy into a form more usable by the cell (ATP) 7. Prokaryote- a cell that lacks a nucleus or organelles (bacterial cells). 8. Phospholipid- molecule that make up cell membrane. 9. Organelle- structure inside the cell that carries out a specific function. 10. Selectively Permeable-property of cell membranes that allows certain things to enter the cell while others cannot enter the cell. 11. Cell theory-Concept of biology that states all living things are made of cells and all cells come from pre-existing cells. Animal Cell 10. 9. 1. 2. 8. 3. 4. 7. 5. 6. http://s3.amazonaws.com/edcanvas-uploads/98916/local/1373137045/preview_html_59615c41.png Animal Cell • • • • • • • 1. Mitochondria 2. cell membrane 3. Ribosome 4. Centrioles 5. Golgi Body 6. Lysosome 7. Rough Endoplasmic Reticulum (ER) • 8. Nucleus • 9. Smooth Endoplasmic Reticulum (ER) • 10. Cytoplasm Plant Cell 10. 1. 9. 2. 8. 3. 7. 4. 5. 6. Plant Cell • 1. Nucleus • 2. Rough ER and Ribosomes • 3. Mitochondria • 4. Golgi Body • 5. Chloroplasts • 6. Cell Wall • • • • 7. Cell Membrane 8. Cytoplasm 9. Central Vacuole 10. Smooth ER 7-1 Objectives • List the three parts of the cell theory. • Determine why cells have to be relatively small. • Compare the structure of prokaryotic cells to that of eukaryotic cells. Discovery of Cells • Robert Hooke – Looked at non-living cells in cork using a crude microscope in 1665 – Called them cells because they reminded him of a monk’s room • Anton van Leeuwenhoek – First to observe living organisms (in pond water and bacteria from his own mouth) http://www.arsmachina.com/images/hooke.jpg http://askabiologist.asu.edu/research/buildingblocks/images/hookecorkS.jpg Cell Theory 1. All living things are made up of cells 2. Cells are the basic units of structure and function in organisms 3. All cells arise from other living cells http://peer.tamu.edu/curriculum_modules/Cell_Biology/module_1/levels%20of%20organization.jpg Why are cells small? Why can’t I have a cell the size of a minivan? http://www.eatel.net/~dacinc/minivan.jpg Cells Must Be Small • All substances that enter or leave the cell must cross the cell’s surface • The cell needs to maintain a high surface area to volume ratio • Large cells cannot take in nutrients and get rid of waste fast enough for the cell to survive. http://library.thinkquest.org/C006669/media/Biol/img/surface_area_to_volume_ratio.gif Common Features of All Cells 1. Cell membrane A. keeps cell conditions different from outside environment B. regulates what enters or leaves the cell 2. Cytoplasm A. inside the cell membrane and outside the nucleus B. Jell-O like substance http://www.daylilies.org/ahs_dictionary/cytoplasm.gif Common Features of All Cells 3. Cytoskeleton A. Support for organelles 4. Ribosomes A. Help make proteins http://www.uic.edu/classes/bios/bios100/lecturesf04am/cytoskeleton.jpg Prokaryotic vs Eukaryotic http://www.phschool.com/science/biology_place/biocoach/images/cells/allcell.jpg Prokaryotic cells do not contain internal compartments Prokaryotes A. No nucleus and no compartments B. 3.5 billion years old http://english.pravda.ru/img/2005/11/bacteria.jpg Eukaryotic cells are well organized Eukaryotes A. Have a nucleus which holds DNA B. Organelles carry out specific activities Prokaryotes Eukaryotes 7-1 Review Questions 1. Why do cells have to be small? 2. Name four structures that are common to all cells. 3. What is the difference between a prokaryotic and eukaryotic cell? 7-2 Objectives • Describe the role of the nucleus in cell activities. • Analyze the importance of cell organelles in protein production. • Summarize the importance of mitochondria in eukaryotic cells. • Identify three structures in plant cells that are absent in plant cells. How is a cell like a factory? Nucleus – “The Boss” Directs All Cell Activities and Stores DNA 1. Nuclear envelope – surrounds nucleus 2. Nuclear pores – helps substances move into and out of the nucleus http://spectorlab.cshl.edu/images/NucleusModel.jpg DNA (“Blueprint”) is Stored in the Nucleus A. When the cell is not dividing – chromatin B. When cell is dividing – condenses into chromosomes http://homepage.smc.edu/hgp/images/cell-to-DNA.jpeg The Cell Membrane – “Security” Controls what enters and leaves the cell A. Selectively Permeable = only lets certain things through B. Proteins in the membrane “check ID” http://sun.menloschool.org/~cweaver/cells/c/cell_membrane/fluid_mosaic.jpg Production of Proteins – “Manufacturing” 1. Ribosomes – Make proteins that remain in the cell 2. Rough Endoplasmic Reticulum (ER) – Makes proteins that are exported from the cell or to specialized organelles http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/images/endoplasmicreticulumfigure1.jpg “Manufacturing” 3. Smooth ER – no ribosomes – makes lipids and breaks down toxins • Vesicles (“Mail Carriers”) – membrane bound sacs that transport proteins http://www.nsf.gov/news/overviews/biology/assets/interact07.jpg http://www.unipv.it/webbio/anatcomp/freitas/2006-2007/smooth%20&%20rough.jpg Golgi Apparatus “Customization and Shipping” Gets proteins ready for transport 1. Proteins made in the Rough ER move to Golgi apparatus 2. Enzymes modify the proteins 3. Then they are enclosed in a new vesicle for transport http://www.mie.utoronto.ca/labs/lcdlab/biopic/fig/4.12.jpg Lysosomes – “Maintenance” Function in digestion and waste removal A. Made by Golgi apparatus B. Contain enzymes for digestion C. Recycle a cell’s used parts http://sun.menloschool.org/~cweaver/cells/e/lysosomes/brittanica.jpg http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/images/phagocyt.gif Mitochondria – “The Powerhouse” Converts sugar to energy (ATP) A. Inner membrane is highly folded – creates more surface area – many complex chemical reactions occur here B. Muscle cells have a lot of mitochondria http://www.octc.kctcs.edu/gcaplan/anat/images/Image337.gif Mitochondria – “The Powerhouse” http://micro.magnet.fsu.edu/cells/mitochondria/images/mitochondriafigure1.jpg Mitochondria and Chloroplasts have their own DNA! Mitochondrial DNA • Inherited through mother • Mitochondria could once have been freeliving organisms => Endosymbiosis 1) can explain the origins of eukaryotic cells 2) one small cell came to live inside another http://www.accessexcellence.org/RC/AB/WYW/lander/images/inheritance_chart.gif Endosymbiosis http://www.sirinet.net/~jgjohnso/endosymbiosis.jpg Plants cells have certain structures that Animal cells lack 1. Cell Wall A. Supports and protects B. Contains cellulose http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0076.JPG 2. Chloroplasts – “Solar Power!” Converts sunlight into carbohydrates A. Found in plants and green algae B. Like mitochondria, contain their own DNA http://micro.magnet.fsu.edu/cells/chloroplasts/images/chloroplastsfigure1.jpg 3. Central Vacuole – “Storage” Stores water and other substances A. When full, makes cell rigid B. Enables plants to stand upright http://www.progressivegardens.com/knowledge_tree/plantcell.jpg Review Questions 1. What is the difference between Rough and Smooth ER? 2. What is the function of mitochondria? 3. Which cell organelle is the shipping and packaging center for the cell? 4. What are the functions of lysosomes? 5. Why do mitochondria and chloroplasts have their own DNA? 6. Name three structures found in plant cells that are not found in animal cells