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Chapter 7: Cell Structure and Function Section 7-1: Life is Cellular Harvard - Inner Life of the Cell Slide 2 The observations and conclusions of many scientists helped to develop the current understanding of the cell Put it in perspective: 1605 English settlers found the colony at Jamestown, Virginia Slide 3 The Cell Theory Robert Hooke (1665) English physicist used primitive compound microscope to look at plant tissue (cork). He called the chambers cells because they reminded him of the small rooms in a monastery Slide 4 The Cell Theory Rudolph Virchow (1855) Proposes that all cells come from existing cells Where did the first cell come from? Slide 5 THE CELL THEORY 1. All living things are composed of cells. 2. Cells are the basic unit of structure and function in living things. 3. New cells are produced from existing cells. Slide 6 How small are cells? How much is a micrometer? 1 micrometer (m) = 1/1,000,000 m Typical cell size = 5 to 50 m in diameter In a dice that is 1 cm 3 We could fit 1,000,000 cells Cells Alive Slide 7 How small are cells? Slide 8 Two categories of cells 1. Prokaryotic Cells pro = before; karyon = nucleus or kernel contain cell membranes and cytoplasm but no nucleus DNA is scattered through cytoplasm examples: bacteria Slide 9 2. Eukaryotic Cells eu = true; karyon = nucleus or kernel contain a nucleus that holds DNA and membrane bound organelles that have specific functions examples: all plants, animals, some fungi, some microorganisms Two categories of cells Slide 10 ProkaryoticEukaryotic -No Nucleus-Nucleus -Smaller Ribosomes less complex -Less complex -DNA is linear - Ribosomes larger and complex -Membrane bound organelles -Complex -Cell wall (plants and bacteria) -DNA is circular -Cell membrane -DNA -Cytoplasm -Ribosomes Slide 11 Animal Cell - Eukaryotic Prokaryotic Plant Cell - Eukaryotic Slide 12 7-2 Cell Structures Organelle a specialized structure that performs a specific function inside a cell Cytoplasm Found between the nucleus and cell membrane Structure a clear jelly-like fluid Function supports the organelles Slide 13 The Nucleus Nuclear Envelope Found: around the outside of the nucleus Structure: two thin membranes with thousands of pores Function: allows materials to move in and out of the nucleus. Slide 14 The Nucleus Chromatin Nuclear Envelope Nucleus Found In cytoplasm near middle of cell Structure filled with chromatin (tightly coiled DNA) Function: Contains the cells DNA, the instructions for making protein and directing cell activities. Slide 15 Cytoskeleton Found: Throughout the cell Structure: A network of protein filaments Microtubules (25 nm) Microfilaments (7nm) Function: Helps support the cell & maintain shape Involved in several types of movement Slide 16 Vacuoles Found: In the cytoplasm Structure: Saclike Very large in plant cells Smaller in animal cells Function: Storage (water proteins, carbs, salts) Slide 17 Vesicles Found: In the cytoplasm Structure: membrane bounded sac Function: transports and/or stores cellular products Slide 18 Lysosomes The Cells Clean-up Crew Found: In the cytoplasm Structure: Small enzyme filled organelles Function: Breakdown large organic molecules, and old nonfunctioning organelles Slide 19 Ribosomes Found: In the cytoplasm Structure: Small and grain-like, made of large and small subunits Function: produce proteins from directions given by DNA Slide 20 Endoplasmic Reticulum Found: just outside the nucleus Structure: a maze of membranes Rough ER: (ribosomes imbedded in membrane) produces and transports proteins. Slide 21 Golgi Apparatus Found: In the cytoplasm Structure: A stack of membranes Function: to modify, sort and package materials from the ER for storage or to be transported outside the cell. Slide 22 Chloroplast Found: In the cytoplasm of plant cells Structure: Stack of membranes that contain photosynthetic pigments (chlorophyll) Function: Use energy from the sun to make food (photosynthesis) Slide 23 Mitochondria Powerhouse of the Cell Found: In the cytoplasm Structure: Rod-shaped with a folded double membrane Function: Provide the cell with energy. Slide 24 Cell Wall Found: Located outside the cell membrane Structure: Fibers of carbohydrate, cellulose in plant cells Function: Provide support and protection for the cell Slide 25 Cell Membrane Found: Located around the perimeter of the cell Structure: Made of a phospholipid bilayer Function: Regulates what leaves and enters the cell and provides protection and support Slide 26 Centrioles Found: Within the cytoplasm only in animal cells Structure: Made of a microtubules (tubulin) Function: Help organize the cell during cell during division. Centrioles - Miosis Slide 27 1. What are the three parts of the cell theory. 2. Who is credited with discovering cells? 3. What is the typical size range for cells in micrometers? 4. How did plant cells appear under the microscope? 5. What type of cell is this and name an organism it could have come from. Warm up questions. Slide 28 Read the passage about prokaryotic and eukaryotic cells. Complete a Venn Diagram like the one in your notes detailing the similarities and differences between prokaryotic and eukaryotic cells. Lastly, based on the passage write a short paragraph detailing how we think eukaryotic cells may have evolved from prokaryotic cells. Eukaryotic and Prokaryotic Cells Slide 29 Bryson Reading: Bacteria Multiplying White blood cell vs. bacterium Bonnie Bassler Slide 30 Slide 31 According to endosymbiotic theory, what two eukaryotic organelles are believed to have been former prokaryotic cells? Bonus question (3 pts.) Slide 32 Get a book from the back and turn to pages 162-163. In your notebook construct a Venn diagram that compares and contrasts prokaryotic and eukaryotic cells After exam: Prokaryotic Eukaryotic Slide 33 3. 2. 1.