Presentation on theme: "Chapter 7: Cell Structure and Function"— Presentation transcript:
1 Chapter 7: Cell Structure and Function Section 7-1: Life is CellularHarvard - Inner Life of the Cell
2 The observations and conclusions of many scientists helped to develop the current understanding of the cellPut it in perspective:1605 – English settlers found the colony at Jamestown, Virginia
3 The Cell TheoryRobert 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
4 The Cell Theory Rudolph Virchow (1855) Proposes that all cells come from existing cellsWhere did the first cell come from?
5 THE CELL THEORY All living things are composed of cells. Cells are the basic unit of structure and function in living things.New cells are produced from existing cells.
6 How small are cells? How much is a micrometer? 1 micrometer (µm) = 1/1,000,000 mTypical cell size = 5 to 50 µm in diameterIn a dice that is 1 cm3We could fit 1,000,000 cellsCells Alive
8 Two categories of cells 1. Prokaryotic Cellspro = before; karyon = nucleus or kernelcontain cell membranes and cytoplasm but no nucleusDNA is scattered through cytoplasmexamples: bacteria
9 Two categories of cells 2. Eukaryotic Cellseu = true; karyon = nucleus or kernelcontain a nucleus that holds DNA and membrane bound organelles that have specific functionsexamples: all plants, animals, some fungi, some microorganisms
10 Two categories of cells ProkaryoticEukaryotic-No Nucleus-Nucleus-Cell wall (plants and bacteria)-Complex-Less complex-Membrane bound organelles-Smaller Ribosomes less complex-Cell membrane-DNA- Ribosomes larger and complex-Cytoplasm-DNA is circular-Ribosomes-DNA is linear
12 7-2 Cell StructuresOrganelle – a specialized structure that performs a specific function inside a cellCytoplasmFound – between the nucleus and cell membraneStructure – a clear jelly-like fluidFunction – supports the organelles
13 The Nucleus Nuclear Envelope Found: around the outside of the nucleus Structure: two thin membranes with thousands of poresFunction: allows materials to move in and out of the nucleus.
14 The Nucleus Found – In cytoplasm near middle of cell Structure – filled with chromatin (tightly coiled DNA)Function: Contains the cell’s DNA, the instructions for making protein and directing cell activities.ChromatinNucleusNuclear Envelope
15 Cytoskeleton Found: Throughout the cell Structure: A network of protein filamentsMicrotubules (25 nm)Microfilaments (7nm)Function: Helps support the cell & maintain shapeInvolved in several types of movement
16 Vacuoles Found: In the cytoplasm Structure: Saclike Very large in plant cellsSmaller in animal cellsFunction: Storage (water proteins, carbs, salts)
17 Vesicles Found: In the cytoplasm Structure: membrane bounded sac Function: transports and/or stores cellular products
18 Lysosomes “The Cells Clean-up Crew” Found: In the cytoplasm Structure: Small enzyme filled organellesFunction: Breakdown large organic molecules, and old nonfunctioning organelles
19 Ribosomes Found: In the cytoplasm Structure: Small and grain-like, made of large and small subunitsFunction: produce proteins from directions given by DNA
20 Endoplasmic Reticulum Found: just outside the nucleusStructure: a maze of membranesRough ER: (ribosomes imbedded in membrane) produces and transports proteins.
21 Golgi Apparatus Found: In the cytoplasm Structure: A stack of membranesFunction: to modify, sort and package materials from the ER for storage or to be transported outside the cell.
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)
23 Mitochondria “Powerhouse of the Cell” Found: In the cytoplasmStructure: Rod-shaped with a folded double membraneFunction: Provide the cell with energy.
24 Cell Wall Found: Located outside the cell membrane Structure: Fibers of carbohydrate, cellulose in plant cellsFunction: Provide support and protection for the cell
25 Cell Membrane Found: Located around the perimeter of the cell Structure: Made of a phospholipid bilayerFunction: Regulates what leaves and enters the cell and provides protection and support
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
27 Warm up questions. 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.
28 Eukaryotic and Prokaryotic Cells 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.
29 Bryson Reading: Bacteria Multiplying White blood cell vs. bacterium Bonnie Bassler
31 Bonus question (3 pts.)According to endosymbiotic theory, what two eukaryotic organelles are believed to have been former prokaryotic cells?
32 After exam: Prokaryotic Eukaryotic Get a book from the back and turn to pages In your notebook construct a Venn diagram that compares and contrasts prokaryotic and eukaryotic cellsProkaryoticEukaryotic