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CHAPTER 7: CELL STRUCTURE AND FUNCTION Scanning Electron Microscope: Specimen Cells http://micro.magnet.fsu.edu/primer/java/electronmicroscopy/magnify1/index.html Fat cells Nerve Cells Red Blood Cells More Cells More Cells! 7-1 Life Is Cellular A. The Discovery of the Cell 1. Early Microscopes • Robert Hooke- Used compound microscope to look at a slice of cork • Anton van Leeuwenhoek- Observed tiny living things in pond water 2. The Cell Theory • Mathias Schleiden-Concluded all plants are made of cells • Theodor Schwann- Stated all animals are made of cells • Rudolf Virchow- Concluded new cells come from existing cells Cell Theory: • All living things are composed of _____ cells • Cells are the basic units of structure and function in living things • New cells are produced from Existing cells ____________ B. Exploring the Cell 1. Electron Microscope (TEM & SEM) -Specimen placed in a vacuum http://www.mos.org/sln/sem/ 2. Scanning Probe Microscope -1990 development of fine probe microscope ordinary air -operates in _______________ -can even show samples in solution C. Prokaryotes and Eukaryotes 0.2 micrometers • cells vary in size from _________________1000 micrometers ___________________ • viruses are not cells Prokaryotic cell Cell membrane Eukaryotic cell Cytoplasm Cell membrane Organelles Cytoplasm Nucleus Prokaryotes Common to Both before pro=__________ contain DNA __________ karyote= kernel (nucleus) Cell generally smaller membrane less complicated no Membrane bound organelles Ex: Kingdom Monera - Eubacteria - Archaea Eukaryotes true Eu= ___________ Karyote=kernel (nucleus) Generally larger Contain membrane bound organelles (“little organs”) Ex: Plants, animals, fungi, and protists Eukaryotic Cell vs. Prokaryotic cell http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm Venn Diagrams 7-2 Eukaryotic Cell Structure(chart) Section 7-2 Prokaryotes Eukaryotes Cell membrane Contain DNA ribosomes Animal Cells Centrioles Lysosomes Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Vacuoles Mitochondria Cytoskeleton http://www.slideshare.net/mgsonline/prokaryotes-vs-eukaryotes Cell Wall Chloroplasts Central Vacuole Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Additional Resources • • Cell Organelles http://www.wisc-online.com/objects/index_tj.asp?objID=AP11604 • • Journey into DNA http://www.pbs.org/wgbh/nova/genome/dna.html# • • Quiz http://www.wisc-online.com/objects/index_tj.asp?objID=AP11604 • • Cytoskeleton http://www.sumanasinc.com/webcontent/animations/content/intermediate_filaments.html artists rendition of the plant cell Section 7-2 Smooth endoplasmic reticulum Vacuole Ribosome (free) Chloroplast Ribosome (attached) Cell Membrane Nuclear envelope Cell wall Nucleolus Golgi apparatus Nucleus Mitochondrion Rough endoplasmic reticulum Plant Cell artists rendition of an animal cell Animal cell http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm Animal Cell Ribosome (attached) Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Ribosome (free) Cell Membrane Mitochondrion Smooth endoplasmic reticulum Centrioles Parts Wanted Advertising for Cells’ Organelles Example: HELP WANTED Looking for a great opportunity to lead? Do you enjoy making decisions for others? Is guidance your strong point? If so, we are seeking to fill a managerial position. We are in need of a control center for a cell. Must be able to operate a cell. Should have solid experience reading and de-coding DNA. Should exhibit strong leadership skills. Benefits include: placement in low stress arm cells, long life guaranteed. . You don’t die; you just divide and multiply! If interested contact The Body at 817-8WE-CELL. 7-3 Cell Boundaries A. Cell Membrane • Regulates what ___________ and __________ enters leaves the cell • Provides protection and support lipid bilayer • Composed of a ______________ • __________________ are embedded in the Protein molecules bilayer; form channels and pumps to move material across the cell membrane. • _________________ are attached to some of the Carbohydrates proteins; allows cells to __________ one identify another. Outside of cell CELL MEMBRANE “FLUID MOSAIC” Carbohydrate chains Proteins “ID tags” Cell membrane Inside of cell (cytoplasm) Protein channel “transport” http://www.susanahalpine.com/anim/Life/memb.htm Lipid bilayer “Phospholipids” B. Cell Walls • Found in plants, algae, fungi and many prokaryotes • Cell walls are porous enough to allow water, oxygen, carbon dioxide easily • Main function is to provide support and protection for the cell cellulose • Plant cell walls made of __________ (carbohydrate fiber) C. Diffusion Through Cell Boundaries •All living cells exists in a liquid environment. •Cell membranes regulate the movement of molecules in and out of the cell. selectively permeable •Cell membranes are _____________________ semipermeable (aka: _______________) •If substances can pass, then the cell membrane = Permeable •If substances cannot pass, then the cell membrane= impermeable 1. Measuring Concentration • Cytoplasm= Water and other substances between the cell membrane and the nucleus. • Concentration= mass of solute/volume of solution • Example:12g salt/3L H2O= 4 g/L 60g salt/3L H2O= 20 g/L 5X more concentrated • Concentration gradient= unequal distribution of particles 2. Diffusion • Particles constantly collide and spread out randomly in solution high concentration _____ to a ____ low • Particles move from a _____ concentration (with the concentration gradient); process is diffusion known as _________ • Diffusion continues until equilibrium is reached • Equilibrium = When particles are evenly distributed in solution • Diffusion depends upon random particle movements, without requiring the substances diffuse across membranes ______ cell to use energy _______ • The movement of particles will continue to move equally across the cell membrane to maintain equilibrium. D. Osmosis • H2O passes easily across most membranes • Osmosis = The diffusion of water through a selectively permeable membrane Before Osmosis Selectively permeable membrane After Osmosis water solute Figure 7-15 Osmosis 1. How Osmosis Works Section 7-3 Left Beaker: left side (low water • More sugar molecules on the ____ concentration). • High water concentration on the right side. • The membrane is permeable to water but not sugar. • Net movement of water from high water concentration to low water concentration. TYPES OF SOLUTIONS Hypertonic Solution “above strength” High concentration of Dissolved substances In Solution Isotonic Solution “same strength” Hypotonic Solution “below strength” Equal concentration of dissolved substances Low concentration of dissolved substances in solution Cells in a hypertonic solution In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink. H2O H2O Water Molecule Dissolved Molecule Cells in a hypotonic solution In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell. H2O H2O Water Molecule Dissolved Molecule Cells in an isotonic solution In an isotonic solution, the concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. H 2O H2O Water Molecule Dissolved Molecule 2. The effects of Osmosis on cells (animal cells refer to figure 7-16) Cells in a hypertonic solution Cells in an isotonic solution Cells in a hypotonic solution E. Facilitated Diffusion • Molecules, that cannot diffuse across the cell membrane’s lipid bilayer on their own, can move With the help of protein channels move from high to low concentration • Molecules still ___________________ Facilitated Diffusion Section 7-3 Glucose molecules High Concentration Cell Membrane Low Concentration Protein channel F. Active Transport • Movement of molecules against a concentration gradient (from low to high) • Requires energy • Needs a transport protein or pump Molecule to be carried Energy Molecule being carried Large molecules and clumps of material can be taken into the cell by a process known as ___________. endocytosis The two kinds of endocytosis are: 1. Phagocytosis= ‘Cell eating’ 2. Pinocytosis= ‘cell drinking’ Exocytosis release of large amounts of material ___________= endo/exocytosis demonstration Transport of Large Particles • Endocytosis is a process by which a cell surrounds and takes in material from its environment. Nucleus Digestion Exocytosis Endocytosis Wastes removal 1. interactive sites for cell membrane, diffusion, active, passive transport Let’s Review: PASSIVE TRANSPORT 1.Simple diffusion (includes Osmosis) * No ATP Hi-Lo No protein ACTIVE TRANSPORT 2. Facilitated Diffusion * No ATP * ATP required Hi-Lo Lo-Hi Needs protein Needs Protein 7-4 The Diversity of Cellular Life A. Unicellular Organisms (single celled) • Unicellular organisms _________ outnumber multicellular organisms • Examples: Yeast, algae, bacteria B. Multicellular Organisms (many celled) • Cells become ___________ specialized to perform different tasks • Cells need to communicate and cooperate C. Levels of Organization • The levels of organization in a multicellular organism are: individual CELLS TISSUES ORGANS Section Muscle cell Smooth muscle ( ti ssue) Stomach (organ) ORGAN SYSTEMS Digesti ve system (organ system) 1. Tissues= Group of similar cells that perform a particular function • Four types of tissue: - muscle - epithelial - nervous - connective 2. Organs= Groups of tissues • Ex. bicep muscle is mad of muscle, connective, and nervous tissue 3. Organ Systems= Group of organs that work together to perform a specific function. California State Standards 1. Cell biology a. Cells are enclosed in semipermeable membranes that regulate their interactions with their surroundings c. Know prokaryotic cell differ from eukaryotic cells e. Know the role of endoplasmic reticulum and golgi apparatus in the secretion of proteins g. Students know the role of mitochondria in making stored chemical-bond energy available to cells j. Students know how eukaryotic cells are given shape and internal organization by a cytoskeleton or cell wall or both. Warm-up Section 7-1 1. Name 3 scientists and their contribution to science. 2. What is the cell theory? 3. What are the characteristics of prokaryotes and eukaryotes. Use the “thinking visually” box on page 173 to answer this question. Warm-up Section 7-2 1. 2. 3. 4. 5. Compare and contrast plant and animal cells. Are they prokaryotic or eukaryotic? Eukaryotic cells maintain shape and internal organization with ….? What is the function of the nucleus? Where is chemical energy from food converted to useable energy? Where is light energy converted to chemical energy in plants? What is this process called? Warm-up Section 7-3 1. 2. 3. 4. 5. 6. Describe the anatomy of a cell membrane. What are the main functions of the cell membrane and the cell wall? What happens during diffusion? What is osmosis? Describe the terms hypotonic, hypertonic, isotonic. Compare and contrast passive and active transport. Warm-up Section 7-4 1. What are the levels of organization in a multicellular organism? 2. What is cell specialization? Provide 3 examples. 1. In many cells, the structure that controls the cell’s activities is the a) Cell membrane b) Organelle c) Nucleolus d) Nucleus 2. Despite differences in size and shape, all cells have cytoplasm and a a. Cell wall b. Cell membrane c. Mitochondrion d. Nucleus 3. If a cell of an organism contains a nucleus, the organism is a (an) a. Plant b. Eukaryote c. Animal d. Prokaryote 4. Distinct threadlike structures containing genetic information are called a. Ribosomes b. Chromosomes c. Nuclei d. Mitochondria 5. Which organelle converts the chemical energy in food into a form that cells can use? a. Nucleolus b. Chromosome c. Mitochondrion d. Chloroplast 6. Cell membranes are constructed mainly of a. Lipid bilayers b. Protein pumps c. Carbohydrate gatess d. Free-moving proteins 7. The movement of water molecules across a selectively permeable membrane is known as a. Exocytosis b. Phagocytosis c. Endocytosis d. osmosis 8. A substance that moves across a cell membrane without using the cell’s energy tends to move a. Away from the area of equilibrium b. Away from the area where it is less concentrated c. Away from the area where it is more concentrated d. Toward the area where it is more concentrated 9. Which cell helps in gas exchange in plants? D. Stomata 10. A tissue is composed of a group of a. Similar cells b. Related organelles c. Organ systems d. Related organs Standardized Test Prep 1. Animals cells have all of the following a. b. c. d. e. EXCEPT Mitochondria Chloroplast Nucleus Cell membrane Golgi apparatus STP 2. The nucleus includes all of the following a. b. c. d. e. structures EXCEPT Cytoplasm Nuclear envelope DNA Nucleolus Chromatin STP 3. Which statement best describes the expected result when a typical cell is placed into fresh water? a. b. Active transport of water into the cell would begin There would be a net movement of water out of the cell There would be a net movement of water into the cell Protein synthesis would begin No change in the cell’s water content would occur c. d. e. STP 4. Which cell structures are sometimes a. b. c. d. e. found attached to the ER? Chloroplasts Mitochondria Vacuoles Nuclei Ribosomes STP 5. Which process always involves the a. b. c. d. e. movement of materials from inside the cell to outside the cell? Phagocytosis Endocytosis Diffusion Exocytosis Osmosis STP I. II. III. Which of the following is NOT an example of active transport? Facilitated diffusion Osmosis Diffusion a. b. c. d. e. I only III only I and II only II and III only I, II, and III 6. STP 7. E 8. B 9. D How are prokaryotic and eukaryotic cell alike? How do they differ?