Chapter 3: Cell Structure and Function PDF

PowerPoint® Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University CHAPTER 3 Cell Structure and Function © 2015 Pearson Education, Inc.  Processes of Life Growth Reproduction Responsiveness Metabolism ©...

PowerPoint® Lecture Presentations prepared by Mindy Miller-Kittrell, North Carolina State University CHAPTER 3 Cell Structure and Function © 2015 Pearson Education, Inc.  Processes of Life Growth Reproduction Responsiveness Metabolism © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Figure 3.1 Examples of types of cells. © 2015 Pearson Education, Inc.  Processes of Life Tell Me Why The smallest free-living microbe—the bacterium Mycoplasma—is nonmotile. Why is it alive, even though it cannot move? © 2015 Pearson Education, Inc.  Mycoplasma Mycoplasma can replicate and reproduce itself through binary fission, where one cell divides into two daughter cells. This ability to reproduce is a fundamental characteristic of living organisms. © 2015 Pearson Education, Inc.  Mycoplasma Mycoplasma has metabolic processes that allow it to obtain energy and nutrients from its environment. It can metabolize various substances for energy and growth, albeit in a limited manner compared to more complex organisms. © 2015 Pearson Education, Inc.  Mycoplasma Mycoplasma maintains internal stability (homeostasis) despite changes in its external environment. It regulates its internal conditions to ensure optimal functioning and survival. © 2015 Pearson Education, Inc.  Mycoplasma While Mycoplasma lacks certain features commonly associated with motility, such as flagella or cilia, its ability to survive and thrive in diverse environments showcases its adaptation and resilience as a living organism. Thus, despite being nonmotile, Mycoplasma possesses the essential characteristics necessary for life. © 2015 Pearson Education, Inc.  Eukaryotic vs Prokaryotic © 2015 Pearson Education, Inc.  Structures © 2015 Pearson Education, Inc.  Prokaryotic and Eukaryotic Cells: An Overview Prokaryotes Include bacteria and archaea Have a simple structure Lack nucleus Lack various membrane-bound internal structures Are typically 1.0 µm in diameter or smaller © 2015 Pearson Education, Inc.  Figure 3.2 Typical prokaryotic cell. Inclusions Ribosome Cytoplasm Nucleoid Flagellum Glycocalyx Cell wall Cytoplasmic membrane © 2015 Pearson Education, Inc.  Prokaryotic and Eukaryotic Cells: An Overview Eukaryotes Have nucleus Have internal membrane-bound organelles Are typically 10–100 µm in diameter Have more complex structure Include algae, protozoa, fungi, animals, and plants © 2015 Pearson Education, Inc.  Figure 3.3 Typical eukaryotic cell. Nuclear envelope Nuclear pore Nucleolus Lysosome Mitochondrion Centriole Secretory vesicle Golgi body Cilium Transport vesicles Ribosomes Rough endoplasmic reticulum Smooth endoplasmic reticulum Cytoplasmic membrane Cytoskeleton © 2015 Pearson Education, Inc.  Figure 3.4 Approximate size of various types of cells. © 2015 Pearson Education, Inc.  Prokaryotic and Eukaryotic Cells: An Overview Tell Me Why In 1985, an Israeli scientist discovered a single-celled microbe, Epulopiscium fishelsoni. This organism is visible with the naked eye. Why did the scientist think Epulopiscium was eukaryotic? What discovery revealed that the microbe is really a giant bacterium? © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  External Structures of Bacterial Cells Glycocalyx Gelatinous, sticky substance surrounding the outside of the cell Composed of polysaccharides, polypeptides, or both © 2015 Pearson Education, Inc.  External Structures of Bacterial Cells Two Types of Glycocalyces Capsule Composed of organized repeating units of organic chemicals Firmly attached to cell surface May prevent bacteria from being recognized by host Slime layer Loosely attached to cell surface Water soluble Sticky layer allows prokaryotes to attach to surfaces as biofilms © 2015 Pearson Education, Inc.  Figure 3.5 Glycocalyces. Glycocalyx Glycocalyx (capsule) (slime layer) © 2015 Pearson Education, Inc.  Motility © 2015 Pearson Education, Inc.  External Structures of Bacterial Cells Flagella Are responsible for movement Have long structures that extend beyond cell surface Are not present on all bacteria © 2015 Pearson Education, Inc.  External Structures of Bacterial Cells Flagella Structure Composed of filament, hook, and basal body Basal body anchors the filament and hook to cell wall © 2015 Pearson Education, Inc.  Flagella: Structure © 2015 Pearson Education, Inc.  Figure 3.6 Proximal structure of bacterial flagella. Filament k Direction o of rotation during run o H Rod Peptidoglycan layer (cell wall) Protein rings Cytoplasmic membrane Cytoplasm Filament k o o H Outer protein rings Outer membrane Rod Cell Gram + Gram – Peptidoglycan wall Integral layer Basal protein body Inner protein Cytoplasmic rings membrane Cytoplasm Integral protein © 2015 Pearson Education, Inc.  Figure 3.7 Micrographs of basic arrangements of bacterial flagella. © 2015 Pearson Education, Inc.  Flagella: Arrangement © 2015 Pearson Education, Inc.  Spirochetes © 2015 Pearson Education, Inc.  Spirochetes Spirochetes are long and slender bacteria, usually only a fraction of a micron in diameter but 5 to 250 microns long. They are tightly coiled, and so look like miniature springs or telephone cords. Members of this group are also unusual among bacteria for the arrangement of axial filaments, which are otherwise similar to bacterial flagella. These filaments run along the outside of the protoplasm, but inside an outer sheath; they enable the bacterium to move by rotating in place. You can see these filaments in the picture of Treponema above, which is the only genus to lack the outer sheath. © 2015 Pearson Education, Inc.  Spirochetes The ecological roles of spirochetes are varied; the group includes both aerobic and anaerobic species, and both free-living and parasitic forms. One species, in the genus Cristispira, has only been found growing on the crystalline style in the digestive tract of certain bivalve mollusks. Some species of Treponema live in the rumen of a cow's stomach, where they break down cellulose and other difficult to digest plant polysaccharides for their host. Perhaps the best-known spirochetes are those which cause disease. These include syphilis and Lyme disease, as well as other less well- known ones. © 2015 Pearson Education, Inc.  Syphilis © 2015 Pearson Education, Inc.  Syphilis © 2015 Pearson Education, Inc.  Figure 3.8 Axial filament. Endoflagella rotate Axial filament rotates around Axial filament cell Outer membrane Cytoplasmic membrane Spirochete corkscrews Axial filament and moves © 2015 Pearson Education, Inc. forward  External Structures of Bacterial Cells Flagella Function Rotation propels bacterium through environment Rotation reversible; can be counterclockwise or clockwise Bacteria move in response to stimuli (taxis) Runs Tumbles © 2015 Pearson Education, Inc.  Figure 3.9 Motion of a peritrichous bacterium. © 2015 Pearson Education, Inc.  Flagella: Movement © 2015 Pearson Education, Inc.  External Structures of Bacterial Cells Fimbriae and Pili Fimbriae Sticky, bristlelike projections Used by bacteria to adhere to one another and to substances in environment Shorter than flagella Serve an important function in biofilms © 2015 Pearson Education, Inc.  Figure 3.10 Fimbriae. Flagellum Fimbria © 2015 Pearson Education, Inc.  External Structures of Prokaryotic Cells Pili Special type of fimbria Also known as conjugation pili Longer than fimbriae but shorter than flagella Bacteria typically have only one or two per cell Transfer DNA from one cell to another (conjugation) © 2015 Pearson Education, Inc.  Figure 3.11 Pili. Pilus © 2015 Pearson Education, Inc.  External Structures of Prokaryotic Cells Tell Me Why Why is a pilus a type of fimbria, but a flagellum is not? © 2015 Pearson Education, Inc.  Bacterial Cell Walls Provide structure and shape and protect cell from osmotic forces Assist some cells in attaching to other cells or in resisting antimicrobial drugs Can target cell wall of bacteria with antibiotics Give bacterial cells characteristic shapes Composed of peptidoglycan Scientists describe two basic types of bacterial cell walls Gram-positive and Gram-negative © 2015 Pearson Education, Inc.  Figure 3.12 Bacterial shapes and arrangements. © 2015 Pearson Education, Inc.  Figure 3.13 Comparison of the structures of glucose, NAG, and NAM. © 2015 Pearson Education, Inc.  Figure 3.14 Possible structure of peptidoglycan. Sugar chain Tetrapeptide (amino acid) crossbridge Connecting chain of amino acids © 2015 Pearson Education, Inc.  Bacterial Cell Walls Gram-Positive Bacterial Cell Walls Relatively thick layer of peptidoglycan Contain unique polyalcohols called teichoic acids Appear purple following Gram staining procedure Presence of up to 60% mycolic acid in acid-fast bacteria helps cells survive desiccation © 2015 Pearson Education, Inc.  Figure 3.15a Comparison of cell walls of Gram-positive and Gram-negative bacteria. Peptidoglycan layer (cell wall) Cytoplasmic membrane Gram-positive cell wall Lipoteichoic acid Teichoic acid Integral protein © 2015 Pearson Education, Inc.  Prokaryotic Cell Walls Gram-Negative Bacterial Cell Walls Have only a thin layer of peptidoglycan Bilayer membrane outside the peptidoglycan contains phospholipids, proteins, and lipopolysaccharide (LPS) Lipid A portion of LPS can cause fever, vasodilation, inflammation, shock, and blood clotting May impede the treatment of disease Appear pink following Gram staining procedure © 2015 Pearson Education, Inc.  Figure 3.15b Comparison of cell walls of Gram-positive and Gram-negative bacteria. Porin Outer Porin membrane (sectioned) of cell wall Peptidoglycan layer of cell wall Periplasmic space Cytoplasmic Gram-negative cell wall membrane Phospholipid layers Lipopolysaccharide (LPS) layer, containing Integral lipid A proteins © 2015 Pearson Education, Inc.  Prokaryotic Cell Walls Bacteria Without Cell Walls A few bacteria lack cell walls Often mistaken for viruses because of small size and lack of cell wall Have other features of prokaryotic cells, such as ribosomes © 2015 Pearson Education, Inc.  Prokaryotic Cell Walls Tell Me Why Why is the microbe illustrated in Figure 3.2 more likely a Gram-positive bacterium than a Gram-negative one? © 2015 Pearson Education, Inc.  Bacterial Cytoplasmic Membranes Structure Referred to as phospholipid bilayer Composed of lipids and associated proteins Integral proteins Peripheral proteins Fluid mosaic model describes current understanding of membrane structure © 2015 Pearson Education, Inc.  Figure 3.16 The structure of a prokaryotic cytoplasmic membrane: a phospholipid bilayer. Head, which contains phosphate (hydrophilic) Phospholipid Tail (hydrophobic) Integral proteins Cytoplasm Integral protein Phospholipid bilayer Peripheral protein Integral protein © 2015 Pearson Education, Inc.  Membrane Structure © 2015 Pearson Education, Inc.  Bacterial Cytoplasmic Membranes Function Control passage of substances into and out of the cell Energy storage Harvest light energy in photosynthetic bacteria Selectively permeable Naturally impermeable to most substances Proteins allow substances to cross membrane Maintain concentration and electrical gradient © 2015 Pearson Education, Inc.  Membrane Permeability © 2015 Pearson Education, Inc.  Cell Permeability 1.The cell membrane is a semi-permeable membrane that allows only selected molecular entities to pass through it. 2.The ease with which a molecule can pass through the cell membrane is known as the permeability of the cell membrane. 3.It also refers to the rate at which the passive diffusion occurs through the cell membrane. © 2015 Pearson Education, Inc.  Figure 3.17 Electrical potential of a cytoplasmic membrane. Na+ Cl– Cell exterior (extracellular fluid) –30 –70 0 mV Cytoplasmic membrane Integral protein Protein DNA Protein © 2015 Pearson Education, Inc. Cell interior (cytoplasm)  Passive Transport: Principles of Diffusion © 2015 Pearson Education, Inc.  Bacterial Cytoplasmic Membranes Function Passive processes Diffusion Facilitated diffusion Osmosis © 2015 Pearson Education, Inc.  Figure 3.18 Passive processes of movement across a cytoplasmic membrane. © 2015 Pearson Education, Inc.  Figure 3.19 Osmosis, the diffusion of water across a semipermeable membrane. © 2015 Pearson Education, Inc.  Figure 3.20 Effects of isotonic, hypertonic, and hypotonic solutions on cells. Cells without a wall (e.g., mycoplasmas, H2O H2O animal cells) H2O Cell wall Cell wall Cells with a wall H2O H2O H2O (e.g., plants, fungal and bacterial cells) Cell membrane Cell membrane Isotonic Hypertonic Hypotonic solution solution solution © 2015 Pearson Education, Inc.  Passive Transport: Special Types of Diffusion © 2015 Pearson Education, Inc.  1. Diffusion It is the movement of substances from an area of high concentration to an area of low concentration until the concentration becomes equal in both regions. The two common types of diffusion are: Simple Diffusion: It occurs without the help of any protein molecule. Examples: The movement of water, oxygen, carbon dioxide, ethanol, and urea. Facilitated Diffusion: It is a selective process that occurs with the help of a transmembrane protein molecule. Facilitated diffusion can occur either through a channel protein or through a carrier protein. Examples: Transport of glucose, sodium ions, and potassium ions. © 2015 Pearson Education, Inc.  2. Osmosis The spontaneous movement of water molecules from a region of low solute concentration to a region of high solute concentration through a semipermeable membrane. It is a selective process that allows only solvent molecules to pass while restricting the solutes. Examples: Taking of nutrients and minerals inside the cell and getting rid of its waste products. © 2015 Pearson Education, Inc.  Prokaryotic Cytoplasmic Membranes Function Active processes Active transport Group translocation Substance is chemically modified during transport © 2015 Pearson Education, Inc.  Figure 3.21 Mechanisms of active transport. Extracellular fluid Uniport Cytoplasmic membrane ATP ATP ADP P ADP P Symport Cytoplasm Uniport Antiport Coupled transport: uniport and symport © 2015 Pearson Education, Inc.  Active Transport: Overview © 2015 Pearson Education, Inc.  Active Transport: Types © 2015 Pearson Education, Inc.  Figure 3.22 Group translocation. © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Prokaryotic Cytoplasmic Membranes Tell Me Why E. coli grown in a hypertonic solution turns on a gene to synthesize a protein that transports potassium into the cell. Why? © 2015 Pearson Education, Inc.  E. Coli matters. When E. coli is grown in a hypertonic (high salt concentration) solution, it experiences osmotic stress. Osmotic stress occurs when there's a concentration gradient across a semipermeable membrane, leading to the movement of water out of the cell to balance the solute concentration outside. To counteract the loss of water and prevent dehydration, E. coli needs to regulate its internal osmotic pressure. One of the mechanisms it employs is to increase the uptake of potassium ions (K⁺) into the cell. Potassium ions are important for maintaining osmotic balance and stabilizing the cell's internal environment. © 2015 Pearson Education, Inc.  E. Coli cont… The gene that synthesizes the protein responsible for transporting potassium ions into the cell is activated in response to osmotic stress. This protein, often a potassium transporter or channel, helps the cell maintain proper osmotic balance by increasing the concentration of potassium ions inside the cell. As a result, water uptake is facilitated, helping to counteract the osmotic stress caused by the hypertonic environment. © 2015 Pearson Education, Inc.  Cytoplasm of Bacteria Cytosol Liquid portion of cytoplasm Mostly water Contains cell's DNA in region called the nucleoid Inclusions May include reserve deposits of chemicals © 2015 Pearson Education, Inc.  Figure 3.23 Granules of PHB in the bacterium Azotobacter chroococcum. Polyhydroxybutyrate © 2015 Pearson Education, Inc.  Cytoplasm of Bacteria Endospores Unique structures produced by some bacteria Defensive strategy against unfavorable conditions Vegetative cells transform into endospores when nutrients are limited Resistant to extreme conditions such as heat, radiation, chemicals © 2015 Pearson Education, Inc.  Figure 3.24 The formation of an endospore. Cytoplasmic Cell wall membrane Steps in Endospore Formation 1 DNA is replicated. 5 Spore coat forms Spore coat DNA around endospore. Vegetative cell Outer 6 Endospore matures: spore coat 2 Cytoplasmic membrane Forespore Completion of spore coat. invaginates to form Increase in resistance forespore. to heat and chemicals by unknown process. Endospore 7 Endospore is released from original cell. 3 Cytoplasmic membrane First grows and engulfs membrane forespore within a second membrane. Vegetative cell's DNA disintegrates. Second membrane 8 4 A cortex of pepti- doglycan is deposited Cortex between the membranes; meanwhile, dipicolinic acid and calcium ions accumulate within the center of the endospore. © 2015 Pearson Education, Inc.  Cytoplasm of Prokaryotes Nonmembranous Organelles Ribosomes Sites of protein synthesis Composed of polypeptides and ribosomal RNA 70S ribosome composed of smaller 30S and 50S subunits Many antibacterial drugs act on bacterial ribosomes without affecting larger eukaryotic ribosomes © 2015 Pearson Education, Inc.  Cytoplasm of Prokaryotes Nonmembranous Organelles Cytoskeleton Composed of three or four types of protein fibers Can play different roles in the cell Cell division Cell shape Segregation of DNA molecules Movement through the environment © 2015 Pearson Education, Inc.  Figure 3.25 A simple helical cytoskeleton. © 2015 Pearson Education, Inc.  Cytoplasm of Prokaryotes Tell Me Why The 2001 bioterrorist anthrax attack in the U.S. involved Bacillus anthracis. Why is B. anthracis able to survive in mail? © 2015 Pearson Education, Inc.  External Structures of Archaea Glycocalyces Function in the formation of biofilms Adhere cells to one another and inanimate objects Flagella Consist of basal body, hook, and filament Numerous differences from bacterial flagella Fimbriae and Hami Many archaea have fimbriae Some make fimbria-like structures called hami Function to attach archaea to surfaces © 2015 Pearson Education, Inc.  Figure 3.26 Archaeal hami. Hamus Grappling hook Prickles © 2015 Pearson Education, Inc.  External Structures of Archaea Tell Me Why Why do scientists consider bacterial and archaeal flagella to be analogous rather than evolutionary relations? © 2015 Pearson Education, Inc.  Archaeal Cell Walls and Cytoplasmic Membranes Most archaea have cell walls Do not have peptidoglycan Contain variety of specialized polysaccharides and proteins All archaea have cytoplasmic membranes Maintain electrical and chemical gradients Control import and export of substances from the cell © 2015 Pearson Education, Inc.  Figure 3.27 Representative shapes of archaea. © 2015 Pearson Education, Inc.  Archaeal Cell Walls and Cytoplasmic Membranes Tell Me Why Why did scientists in the 19th and early 20th centuries think that archaea were bacteria? © 2015 Pearson Education, Inc.  Cytoplasm of Archaea Archaeal cytoplasm similar to bacterial cytoplasm 70S ribosomes Fibrous cytoskeleton Circular DNA Archaeal cytoplasm also differs from bacterial cytoplasm Different ribosomal proteins Different metabolic enzymes to make RNA Genetic code more similar to that of eukaryotes © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Cytoplasm of Archaea Tell Me Why Why do some scientists consider archaea, which are prokaryotic, more closely related to eukaryotes than they are to bacteria? © 2015 Pearson Education, Inc.  External Structure of Eukaryotic Cells Glycocalyces Not as organized as prokaryotic capsules Help anchor animal cells to each other Strengthen cell surface Provide protection against dehydration Function in cell-to-cell recognition and communication © 2015 Pearson Education, Inc.  External Structure of Eukaryotic Cells Tell Me Why Why are eukaryotic glycocalyces covalently bound to cytoplasmic membranes, and why don't eukaryotes with cell walls have glycocalyces? © 2015 Pearson Education, Inc.  Eukaryotic Cell Walls and Cytoplasmic Membranes Fungi, algae, plants, and some protozoa have cell walls Composed of various polysaccharides Cellulose is found in plant cell walls Fungal cell walls are composed of cellulose, chitin, and/or glucomannan Algal cell walls are composed of a variety of polysaccharides © 2015 Pearson Education, Inc.  Figure 3.28 A eukaryotic cell wall. Cell wall Cytoplasmic membrane © 2015 Pearson Education, Inc.  Eukaryotic Cell Walls and Cytoplasmic Membranes All eukaryotic cells have cytoplasmic membrane Are a fluid mosaic of phospholipids and proteins Contain steroid lipids to help maintain fluidity Contain regions of lipids and proteins called membrane rafts Localize signaling, protein sorting, and movement Control movement into and out of cell © 2015 Pearson Education, Inc.  Figure 3.29 Eukaryotic cytoplasmic membrane. Cytoplasmic membrane Intercellular matrix Cytoplasmic membrane © 2015 Pearson Education, Inc.  Figure 3.30 Endocytosis. Pseudopod © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Eukaryotic Cell Walls and Cytoplasmic Membranes Tell Me Why Many antimicrobial drugs target bacterial cell walls. Why aren't there many drugs that act against bacterial cytoplasmic membranes? © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Flagella Structure and arrangement Differ structurally and functionally from prokaryotic flagella Within the cytoplasmic membrane Shaft composed of tubulin arranged to form microtubules Filaments anchored to cell by basal body; no hook May be single or multiple; generally found at one pole of cell Function Do not rotate but undulate rhythmically © 2015 Pearson Education, Inc.  Figure 3.31a-b Eukaryotic flagella and cilia. Flagellum Cilia © 2015 Pearson Education, Inc.  Figure 3.31c Eukaryotic flagella and cilia. Cytoplasmic membrane Cytosol Central pair microtubules "9 + 2" Microtubules arrangement (doublet) Cytoplasmic membrane Portion cut away to show transition area from doublets Basal body to triplets and the end of central microtubules Microtubules "9 + 0" (triplet) arrangement © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Cilia Shorter and more numerous than flagella Coordinated beating propels cells through their environment Also used to move substances past the surface of the cell © 2015 Pearson Education, Inc.  Figure 3.32 Movement of eukaryotic flagella and cilia. © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Other Nonmembranous Organelles Ribosomes Larger than prokaryotic ribosomes (80S versus 70S) Composed of 60S and 40S subunits Cytoskeleton Extensive network of fibers and tubules Anchors organelles Produces basic shape of the cell Made up of tubulin microtubules, actin microfilaments, and intermediate filaments © 2015 Pearson Education, Inc.  Figure 3.33 Eukaryotic cytoskeleton. Microtubule Microfilament Actin subunit 7 nm 25 nm Intermediate filament Protein 10 nm Tubulin subunits © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Other Nonmembranous Organelles Centrioles and centrosome Centrioles are composed of nine triplets of microtubules Located in region of cytoplasm called centrosome Not found in all eukaryotic cells Centrosomes play a role in mitosis, cytokinesis, and formation of flagella and cilia © 2015 Pearson Education, Inc.  Figure 3.34 Centrosome. Microtubules Centrosome (made up of two centrioles) Triplet © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Membranous Organelles Nucleus Often largest organelle in cell Contains most of the cell's DNA Semiliquid portion is called nucleoplasm Contains chromatin RNA synthesized in nucleoli present in nucleoplasm Surrounded by nuclear envelope Contains nuclear pores © 2015 Pearson Education, Inc.  Figure 3.35 Eukaryotic nucleus. Nucleolus Nucleoplasm Chromatin Nuclear envelope Two phospholipid bilayers Nuclear pores Rough ER © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Membranous Organelles Endoplasmic reticulum Netlike arrangement of flattened, hollow tubules continuous with nuclear envelope Functions as transport system Two forms Smooth endoplasmic reticulum (SER) Rough endoplasmic reticulum (RER) © 2015 Pearson Education, Inc.  Figure 3.36 Endoplasmic reticulum. Membrane-bound ribosomes Mitochondrion Free ribosome Rough endoplasmic Smooth endoplasmic reticulum (RER) © 2015 Pearson Education, Inc. reticulum (SER)  Cytoplasm of Eukaryotes Membranous Organelles Golgi body Receives, processes, and packages large molecules for export from cell Packages molecules in secretory vesicles that fuse with cytoplasmic membrane Composed of flattened hollow sacs surrounded by phospholipid bilayer Not in all eukaryotic cells © 2015 Pearson Education, Inc.  Figure 3.37 Golgi body. Secretory vesicles Vesicles arriving © 2015 Pearson Education, Inc. from ER  Cytoplasm of Eukaryotes Membranous Organelles Lysosomes, peroxisomes, vacuoles, and vesicles Store and transfer chemicals within cells May store nutrients in cell Lysosomes contain catabolic enzymes Peroxisomes contain enzymes that degrade poisonous wastes © 2015 Pearson Education, Inc.  Figure 3.38 Vacuole. Cell wall Nucleus Central vacuole Cytoplasm © 2015 Pearson Education, Inc.  Figure 3.39 The roles of vesicles in endocytosis and exocytosis. Endocytosis (phagocytosis) Bacterium Smooth endoplasmic Phagosome reticulum (food vesicle) (SER) Vesicle Transport fuses with a vesicle lysosome Lysosome Phagolysosome Golgi body Secretory vesicle Exocytosis © 2015 Pearson Education, Inc. (elimination, secretion)  Cytoplasm of Eukaryotes Membranous Organelles Mitochondria Have two membranes composed of phospholipid bilayer Produce most of cell's ATP Interior matrix contains 70S ribosomes and circular molecule of DNA © 2015 Pearson Education, Inc.  Figure 3.40 Mitochondrion. Outer membrane Inner membrane Crista Matrix © 2015 Pearson Education, Inc. Ribosomes  Cytoplasm of Eukaryotes Membranous Organelles Chloroplasts Light-harvesting structures found in photosynthetic eukaryotes Use light energy to produce ATP Have two phospholipid bilayer membranes and DNA Have 70S ribosomes © 2015 Pearson Education, Inc.  Figure 3.41 Chloroplast. Granum Stroma Thylakoid Thylakoid space Inner bilayer membrane Outer bilayer © 2015 Pearson Education, Inc. membrane  Cytoplasm of Eukaryotes Endosymbiotic Theory Eukaryotes formed from union of small aerobic prokaryotes with larger anaerobic prokaryotes Smaller prokaryotes became internal parasites Parasites lost ability to exist independently Larger cell became dependent on parasites for metabolism Aerobic prokaryotes evolved into mitochondria Similar scenario for origin of chloroplasts Theory is not universally accepted © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc.  Cytoplasm of Eukaryotes Tell Me Why Colchicine is a drug that inhibits microtubule formation. Why does colchicine inhibit phagocytosis, movement of organelles within the cell, and formation of flagella and cilia? © 2015 Pearson Education, Inc.  Important topics Difference among cilia, flagella, pili, fimberia, pseudopodia. Structure and function of peptidoglycan, lipid A, mycolic acid. Differences between gram positive and gram negative bacteria. Endo vs. exotoxin Special bacteria such as mycoplasma and mycobacterium Structure and function of chloroplast, mitochondria, peroxysome, lysosome Definition of epidemiology, biotechnology, molecular biology, nosocomial infection Transportation across the cell membrane and cell wall, such as simple diffusion, facilitated diffusion, endocytosis, exocytosis © 2015 Pearson Education, Inc.