Chapter Outline. The Living Cell. The Cell Theory. The Nature and Variety of Cells. Cell theory. Observing Cells: The Microscope

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1 Chapter Outline The Living Cell Chapter 21 The Nature and Variety of Cells How Does a Cell Work? Metabolism: Energy and Life Cell Division Great Idea: Life is based on chemistry, and chemistry takes place in cells 1 2 The Cell Theory The Nature and Variety of Cells All living things are composed of cells The cell is the fundamental unit of life All cells arise from previous cells 3 4 Observing Cells: The Microscope Cell theory (1839)Theodor Schwann & Matthias Schleiden all living things are made of cells (50 yrs. later) Rudolf Virchow all cells come from cells 5 6

2 Principles of Cell Theory Cell Size All living things are made of cells Smallest living unit of structure and function of all organisms is the cell All cells arise from preexisting cells (this principle discarded the idea of spontaneous generation) 7 8 What is a cell? A) The largest living units within our bodies. B) Enzymes that "eat" bacteria C) Microscopic fundamental units of all living things. D) All of the above. All cells are too small to be seen with the unaided eye and must be studied with a microscope. A True B False 9 10 Cells Have Large Surface Area-to-Volume Ratio Characteristics of All Cells A surrounding membrane Protoplasm cell contents in thick fluid Organelles structures for cell function Control center with DNA 11 12

3 What does an electron microscope use to illuminate objects? A light B protons C proteins D electrons Molecule Movement & Cells Passive Transport Active Transport Endocytosis (phagocytosis & pinocytosis) Exocytosis Water: Medium for Metabolism Passive Transport No energy required Liquid medium for metabolism and its importance Role of water (H 2 O) Physical properties (e.g., polarity, phases) Chemical properties (e.g., ph, solution) Exquisite and unique properties of H 2 O Move due to gradient differences in concentration, pressure, charge Move to equalize gradient High moves toward low Types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated diffusion An essential and distinctive feature of all cells is a membrane that isolates and protects the interior from the outer environment. A True B False 17 18

4 Diffusion Molecules move to equalize concentration Osmosis Special form of diffusion Fluid flows from lower solute concentration Often involves movement of water Into cell Out of cell Solution Differences & Cells solvent + solute = solution Hypotonic Solutes in cell more than outside Outside solvent will flow into cell Isotonic Solutes equal inside & out of cell Hypertonic Solutes greater outside cell Fluid will flow out of cell Facilitated Diffusion Differentially permeable membrane Channels (are specific) help molecule or ions enter or leave the cell Channels usually are transport proteins (aquaporins facilitate the movement of water) No energy is used Process of Facilitated Transport Protein binds with molecule Shape of protein changes Molecule moves across membrane 23 24

5 Active Transport Endocytosis Molecular movement Requires energy (against gradient) Example is sodium-potassium pump Movement of large material Particles Organisms Large molecules Movement is into cells Types of endocytosis bulk-phase (nonspecific) receptor-mediated (specific) Process of Endocytosis Plasma membrane surrounds material Edges of membrane meet Membranes fuse to form vesicle Forms of Endocytosis Phagocytosis cell eating Pinocytosis cell drinking Exocytosis Reverse of endocytosis Cell discharges material Exocytosis Vesicle moves to cell surface Membrane of vesicle fuses Materials expelled 29 30

6 In which decade were you born? A 1990s B 1980s C 1970s D 1960s E 1950s In which year was Geller s first peerreviewed paper published? A 1964 B 1974 C 1984 D 1994 E In which journal was Geller s first pee-reviewed paper published? A Astrophysical Journal B Astronomical Journal C Journal of Chromatography D Journal of Physics E The Physics Teacher How Does a Cell Work? Cell Membranes Plant Cell Cell Membranes Isolate cell Separates cell parts Transport Individual molecules Specific materials channels Receptors Bind molecules Cell Wall Plants 35 36

7 The Nucleus Nucleus Contains genetic material Prokaryotes No nucleus Eukaryotes Nucleus Double Membrane The Energy Organelles: Chloroplasts and Mitochondria Organelle Specialized structure in cell Chloroplasts Energy transformation chlorophyll Plant cells only Double membrane Mitochondria Produces cells energy Double membrane Own DNA Cytoskeleton Gives cell shape Anchors Allows movement Transport system Within cell Structure Strong filaments Complex web Cytoskeleton Cells that do not contain a nucleus are called: A eukaryotes B prokaryotes C likaryotes 41 42

8 Any specialized structure in the cell is called: A an endoplasmic reticulum B a chromatin C an organelle What is the basic molecular structure of cell membranes? A lipid bilayer B carbohydrate bilayer C protein bilayer The fluid that takes up the spaces between all the complexity of the specialized structures in cells is called: A deionized water B protoplasm C cytoplasm D molasses The cell structure which divides the inside of the cell from the outside is the: A cell membrane B cell coat C nuclear membrane What structure connects plant cells to each other and often account for about a third of a living plant s mass? A middle lamella B cell wall C cell membrane In most cells the most prominent and important interior structure is the: A nucleus B chromosome C endoplasmic reticulum 47 48

9 Which organelle is the place where molecules react with oxygen to produce the cell s energy? A endoplasmic reticulum B mitochondria C chloroplasts More advanced single-celled organism that do contain a nuclei are called: A eukaryotes B prokaryotes C likaryotes The Cell s Energy Currency Metabolism: Energy and Life 51 Adenosine triphosphate (ATP) Provides energy Structure 3 phosphate groups Sugar molecule: ribose adenine Function Removal of phosphate group provides energy 52 Photosynthesis Photosynthesis Convert sunlight to energy Process Energy + CO 2 + H 2 O carbohydrate + O 2 Colors Glycolysis: The First Step in Energy Generation in the Cell Respiration Oxidation of carbohydrate Retrieves energy in glucose Aerobic Process Glycolysis Split glucose Result Pyruvic acid 2 ATP 2 energy carriers Convert energy carriers to 2-3 ATP 1 molecule glucose = 6-8 ATP 53 54

10 Fermentation: A Way to Keep Glycolysis Going Fermentation Anaerobic Inefficient Yeast alcohol Animal cells Lactic acid The Final Stages of Respiration Krebs cycle Glucose broken down CO 2 produced ATP Energy-carrying molecules Result ATP The cell s process of deriving energy form its surroundings is called: A photosynthesis B metabolism C respiration What mechanism do plants use to convert the energy of sunlight into energy stored in carbohydrates? A photosynthesis B metabolism C glycolysis Mitosis Cell Division Mitosis Cell division Not for sexual reproduction Chromosomes Process Copy chromosomes Spindle fibers Migration of chromosomes Nuclear membrane reforms 59 60

11 Meiosis Meiosis Sexual reproduction 1 cell forms 4 gametes Gametes are genetically unique Process Copy chromosomes Crossing over Segregation Segregation again Result 4 daughter cells ½ normal chromosomes Meiosis By what process do most cells divide? A mitosis B meiosis C glycolysis 63 64