Chapter 7 – Inside the CellKey ConceptsSlide 3Grouping CellsProkaryotic Cells – Structural OverviewSlide 6Prokaryotic Cells – Genetic InformationSlide 8Slide 9Prokaryotic Cells – Internal StructureSlide 11Bacterial OrganellesProkaryotic Cells – External StructureSlide 14Slide 15An Introduction to EukaryotesEukaryotic CellsEukaryotes and Prokaryotes ComparedSlide 19Slide 20Slide 21The NucleusSlide 23Rough Endoplasmic ReticulumSlide 25Smooth Endoplasmic ReticulumSlide 27Golgi ApparatusSlide 29RibosomesSlide 31PeroxisomesSlide 33LysosomesSlide 35How Are Materials Delivered to Lysosomes?Slide 37Slide 38Slide 39VacuolesSlide 41MitochondriaSlide 43ChloroplastsSlide 45The Cell WallSlide 47CytoskeletonSlide 49Structure and Function at the Whole-Cell LevelSlide 51How Dynamic Are Eukaryotic Cells?The Nuclear Envelope: A Transport MechanismSlide 54How Are Molecules Imported into the Nucleus?Slide 56Slide 57Slide 58The Endomembrane SystemThe Secretory Pathway HypothesisSlide 61Slide 62The Signal HypothesisSlide 64Slide 65From ER to GolgiInside the Golgi ApparatusHow Are Products Shipped from the Golgi?ExocytosisSlide 70The Dynamic CytoskeletonActin FilamentsActin-Myosin InteractionsSlide 74Intermediate FilamentsMicrotubule StructureSlide 77Microtubule FunctionSlide 79Slide 80Cilia and Flagella: Moving the Entire CellSlide 82Cilia and Flagella StructureSlide 84A Motor Protein in the AxonemeSlide 86Chapter Summary© 2011 Pearson Education, Inc.Chapter 7 – Inside the Cell© 2011 Pearson Education, Inc.Key ConceptsThe structure and function of a cell’s overall shape and composition, as well as individual cell components, are closely related.Molecular “zip codes” aid material transport within a cell.The cell’s cytoskeleton provides a structural framework within the cell, and plays a role in cell division, movement, and transport.© 2011 Pearson Education, Inc.Key ConceptsCells are highly dynamic and integrated; within a cell, thousands of chemical reactions occur every second, molecules are constantly moving across the plasma membrane, cell products are transported along protein fibers, and elements of the cell’s internal skeleton grow and shrink.© 2011 Pearson Education, Inc.Grouping Cells•According to morphology, there are two broad groupings of life: 1. Prokaryotes, which lack a membrane-bound nucleus2. Eukaryotes, which have such a nucleus•According to phylogeny, or evolutionary history, there are three domains:1. Bacteria2. Archaea3. Eukarya – eukaryotic prokaryotic© 2011 Pearson Education, Inc.Prokaryotic Cells – Structural Overview•All prokaryotes lack a membrane-bound nucleus.•Recent advances in microscopy reveal complexity in prokaryotic structure.•Archaeal cell structure is relatively poorly understood.•Bacterial cells vary greatly in size and shape, but most bacteria contain several structural similarities:–Plasma membrane–A single chromosome–Ribosomes, which synthesize proteins–Stiff cell wall© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Prokaryotic Cells – Genetic Information •Most prokaryotic species have one supercoiled circular chromosome found in the nucleoid region of the cell. –The chromosome contains a long strand of DNA and a few supportive proteins. •In addition to the large chromosome, many bacteria contain plasmids.–Small, supercoiled, circular DNA molecules–Plasmids usually contain genes that help the cell adapt to unusual environmental conditions.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Plasmids file:///Users/ericarowe/Documents/UTK%20Biology/UTK%20Bio140%20Fall%202011/Chapter_07/A_PowerPoint_Lecture_Tools/07_Lecture_Outline/Plasmid.html© 2011 Pearson Education, Inc.Prokaryotic Cells – Internal Structure•In addition to the nucleoid chromosome and plasmids, other structures are contained within the cytoplasm:–All prokaryotic cells contain ribosomes, consisting of RNA molecules and protein, for protein synthesis. –Many prokaryotes have internal photosynthetic membranes. –Some prokaryotes have membrane-enclosed organelles (desmosomes).–The inside of many prokaryotic cells is supported by a cytoskeleton of long, thin protein filaments.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Bacterial Organelles•Recently, internal compartments in many bacterial species were discovered.–These compartments qualify as organelles (“little organs”).–An organelle is a membrane-bound compartment inside the cell that contains enzymes or structures specialized for a particular function.–Organelles are common in eukaryotic cells.•Each type of bacterial organelle is found in certain species.•Bacterial organelles perform an array of tasks.© 2011 Pearson Education, Inc.Prokaryotic Cells – External Structure•Some prokaryotes have tail-like flagella on the cell surface that spin around to move the cell.•Most prokaryotes have a cell wall.–Bacterial and archaeal cell walls are a tough, fibrous layer that surrounds the plasma membrane.•Many species have an additional layer outside the cell wall composed of glycolipids.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.An Introduction to Eukaryotes•Eukaryotes range from microscopic algae to 100-meter-tall redwood trees.•Many eukaryotes are multicellular, others are unicellular.•Most eukaryotic cells are larger than most prokaryotic cells.© 2011 Pearson Education, Inc.Eukaryotic Cells•The relatively large size of the eukaryotic cell makes it difficult for molecules to diffuse across the entire cell. –This problem is partially solved by breaking up the large cell volume into several smaller membrane-bound organelles.•The compartmentalization of eukaryotic cells offers two primary advantages:1. Separation of incompatible chemical reactions2. Increasing the efficiency of chemical reactions© 2011 Pearson Education, Inc.Eukaryotes and Prokaryotes Compared•Four key differences between eukaryotic and prokaryotic cells have been identified:1. Eukaryotic chromosomes are found inside a membrane-bound compartment called a nucleus.2. Eukaryotic cells are often much larger.3. Eukaryotic cells contain extensive amounts of internal membrane.4. Eukaryotic cells feature a diverse and dynamic cytoskeleton.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.The Nucleus•The nucleus is large and
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