BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint Lectures for Biology: Concepts & Connections CHAPTER 4 A Tour of the Cell Modules 4.6 4.14 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The largest organelle is usually the nucleus The nucleus is separated from the cytoplasm by the nuclear envelope The nucleus is the cellular control center It contains the DNA that directs the cells activities 4.6 The nucleus is the cells genetic control center ORGANELLES OF THE ENDOMEMBRANE SYSTEM Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.6 Chromatin Nucleolus Pore NUCLEUS Two membranes of nuclear envelope ROUGH ENDOPLASMIC RETICULUM Ribosomes Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The endomembrane system is a collection of membranous organelles These organelles manufacture and distribute cell products The endomembrane system divides the cell into compartments Endoplasmic reticulum (ER) is part of the endomembrane system 4.7 Overview: Many cell organelles are related through the endomembrane system Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The rough ER manufactures membranes Ribosomes on its surface produce proteins 4.8 Rough endoplasmic reticulum makes membrane and proteins Transport vesicle buds off Ribosome Sugar chain Glycoprotein Secretory (glyco-) protein inside transport vesicle ROUGH ER Polypeptide Figure 4.8 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Smooth ER synthesizes lipids In some cells, it regulates carbohydrate metabolism and breaks down toxins and drugs 4.9 Smooth endoplasmic reticulum has a variety of functions Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings SMOOTH ER ROUGH ER Nuclear envelope Ribosomes SMOOTH ERROUGH ER Figure 4.9 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Golgi apparatus consists of stacks of membranous sacs These receive and modify ER products, then send them on to other organelles or to the cell membrane 4.10 The Golgi apparatus finishes, sorts, and ships cell products Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Golgi apparatus Golgi apparatus Receiving side of Golgi apparatus Transport vesicle from ER New vesicle forming Transport vesicle from the Golgi Golgi apparatus Shipping side of Golgi apparatus Figure 4.10 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomes are sacs of digestive enzymes budded off the Golgi 4.11 Lysosomes digest the cells food and wastes LYSOSOME Nucleus Figure 4.11A Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomal enzymes digest food destroy bacteria recycle damaged organelles function in embryonic development in animals Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.11B Rough ER Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Plasma membrane LYSOSOMES Food Engulfment of particle Food vacuole Digestion Lysosome engulfing damaged organelle Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomal storage diseases are hereditary They interfere with other cellular functions Examples: Pompes disease, Tay-Sachs disease 4.12 Connection: Abnormal lysosomes can cause fatal diseases Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Plant cells contain a large central vacuole The vacuole has lysosomal and storage functions 4.13 Vacuoles function in the general maintenance of the cell Central vacuole Nucleus Figure 4.13A Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Protists may have contractile vacuoles Figure 4.13B Nucleus Contractile vacuoles These pump out excess water Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings The various organelles of the endomembrane system are interconnected structurally and functionally 4.14 A review of the endomembrane system Transport vesicle from ER Rough ER Transport vesicle from Golgi Plasma membrane Vacuole Lysosome Golgi apparatus Nuclear envelope Smooth ER Nucleus Figure 4.14 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chloroplasts are found in plants and some protists Chloroplasts convert solar energy to chemical energy in sugars 4.15 Chloroplasts convert solar energy to chemical energy ENERGY-CONVERTING ORGANELLES Chloroplast Stroma Inner and outer membranes Granum Intermembrane space Figure 4.15 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mitochondria carry out cellular respiration This process uses the chemical energy in food to make ATP for cellular work 4.16 Mitochondria harvest chemical energy from food Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.16 Outer membrane MITOCHONDRION Intermembrane space Inner membrane Cristae Matrix Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings A network of protein fibers makes up the cytoskeleton 4.17 The cells internal skeleton helps organize its structure and activities THE CYTOSKELETON AND RELATED STRUCTURES Figure 4.17A Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Microfilaments of actin enable cells to change shape and move Intermediate filaments reinforce the cell and anchor certain organelles Microtubules give the cell rigidity provide anchors for organelles act as tracks for organelle movement Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings MICROFILAMENT Figure 4.17B INTERMEDIATE FILAMENT MICROTUBULE Actin subunitFibrous subunits Tubulin subunit 7 nm10 nm 25 nm Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic cilia and flagella are locomotor appendages that protrude from certain cells A cilia or flagellum is composed of a core of microtubules wrapped in an extension of the plasma membrane 4.18 Cilia and flagella move when microtubules bend Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.18A FLAGELLUM Outer microtubule doublet Plasma membrane Central microtubules Outer microtubule doublet Plasma membrane Electron micrograph of sections: Flagellum Basal body Basal body (structurally identical to centriole) Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Clusters of microtubules drive the whipping action of these organelles Figure 4.18B Microtubule doublet Dynein arm Sliding force Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cells interact with their environments and each other via their surfaces Plant cells are supported by rigid cell walls made largely of cellulose They connect by plasmodesmata, channels that allow them to share water, food, and chemical messages 4.19 Cell surfaces protect, support, and join cells EUKARYOTIC CELL SURFACES AND JUNCTIONS Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 4.19A Vacuole Layers of one plant cell wall Walls of two adjacent plant cells PLASMODESMATA Cytoplasm Plasma membrane Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Animal cells are embedded in an extracellular matrix It is a sticky layer of glycoproteins It binds cells together in tissues It can also have protective and supportive functions Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Tight junctions can bind cells together into leakproof sheets Anchoring junctions link animal cells Communicating junctions allow substances to flow from cell to cell TIGHT JUNCTION ANCHORING JUNCTION COMMUNICATING JUNCTION Plasma membranes of adjacent cells Extracellular matrix Figure 4.19B Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Eukaryotic organelles fall into four functional groups 4.20 Eukaryotic organelles comprise four functional categories Table 4.20 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Table 4.20 (continued) Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings It is almost certain that Earth is the only life- bearing planet in our solar system But it is conceivable that conditions on some of the moons of the outer planets or on planets in other solar systems have allowed the evolution of life 4.21 Connection: Extraterrestrial life-forms may share features with life on Earth Figure 4.21