1 Chapter 7 Cellular Structure and Function 7.1 Cell Discovery and Theory

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Transcript of 1 Chapter 7 Cellular Structure and Function 7.1 Cell Discovery and Theory

  • Slide 1
  • 1 Chapter 7 Cellular Structure and Function 7.1 Cell Discovery and Theory
  • Slide 2
  • 2 The History of the Cell Theory Cells are the basic units of living things Before microscopes people believed diseases were caused by curses and supernatural spirits (wrath of God) The idea that a living thing like a bacteria could cause disease or infection never occurred. Why?
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  • 3 Development of the Light Microscope Today's microscope is a compound microscope with two lenses Eyepiece lens Objective lens Can magnify 1500 times
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  • 4 Simple Light Microscope Developed by Anton van Leeuwenhoek in the mid 1600 One lens Much like a magnifying glass
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  • 5 The Cell Theory Robert Hook First to use the term cell Looked a cork under a microscope, saw the cell walls
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  • 6 Robert Hook Contemporary of Anton van Leeuwenhoek English Published and encouraged others to use microscopes
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  • 7 Matthias Schleiden 1838 German botanists Examined plants of all types All plants are made of cells
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  • 8 Theodore Schwann 1839 German zoologist Contemporary of Schleidens Examined animal tissues of many types All animals are made of cells
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  • 9 Rudolph Virchow 1855 German physician All cells come from preexisting cells
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  • 10 The Cell Theory 1. All organisms are composed of one or more cells Unicellular or multicellular 2. The cell is the basic unit of organization of all organisms Structure Function 3. All cells come from preexisting cells
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  • 11 Technology Since the 1800s Compound light microscopes continued to improve so that bacteria were able to be classified Most magnification possible with light microscopes cannot see inner cell parts
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  • 12 Electron Microscopes Developed in the 1940s Uses magnets to focus a beam of electrons (in place of light) Can magnify 500,000X Several types Scanning: looks at surface; get 3-D Transmission: looks at interior Scanning-Tunneling: atoms on surface
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  • 13 Microscope Aids Both light and electron microscopes use dyes and stains which helps to contrast cell and parts Most dyes and stains kill the cells Most specimens of electron microscopes need to be in a vacuum and/or coated with gold
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  • 14 Two Basic Cell Types Prokaryote Have plasma membrane No internal membrane bound structures Unicellular Smaller in size No specialization Example: bacteria Eukaryote Have plasma membrane Internal membrane bound structures Unicellular and multicellular Larger size Much specialization Example: animal
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  • 15 Two Basic Cell Types ProkaryoteEukaryote
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  • 16 Two Basic Cell Types
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  • 17 Chapter 7 Cellular Structure and Function 7.2 The Plasma Membrane
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  • 18 Plasma Membrane Diagram
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  • 19 Plasma Membrane Micrograph
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  • 20 Plasma Membrane Structure Made of phospholipid bilayer Polar ends are hydrophilic Nonpolar ends are hydrophobic
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  • 21 Plasma Membrane Function Job of plasma membrane is homeostasis- maintain balance For cells to survive they must keep the inside in and the outside out, yet allow some materials to move into and out of the cell
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  • 22 Structure Fits Function The structure of the plasma membrane (how it is put together) allows the plasma membrane its function or job, selective permeability Selective permeability: the ability to allow some materials into or out of the cell but not other materials
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  • 23 Selective Permeability Out side of cell is different from inside of cell
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  • 24 Structure Fits Function Both the inside of the cell and the outside are water environment so the hydrophilic ends face in and out The hydrophobic fatty tails are in the middle so that materials cant pass through easily
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  • 25 Structure Fits Function Role of proteins in plasma membrane Channels or tunnels for substances to pass through with specific fit Identification of organism and tissue type Signal sending proteins Provide support for the phospholipids
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  • 26 Plasma Membrane Proteins
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  • 27 Plasma Membrane Cholesterol stabilizes the plasma membrane in animal cells Animal cells have no cell wall as do plant cell High blood cholesterol is a risk factor for heart disease and stroke Animals (including us) produce cholesterol for the stabilization of the cell membrane
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  • 28 Fluid Mosaic Model
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  • 29 Fluid Mosaic Model FLUID: Plasma membrane in constant motion with the phospholipids of one layer moving one direction and the phospholipids of the other layer moving in the opposite direction MOSAIC: something consisting of a number of different things of different types
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  • 30 Chapter 7 Cellular Structure and Function 7.3 Structures and Organelles
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  • 31 Cellular Boundaries Plant Cell outer most part is the cell wall; plasma membrane is inside of the cell wall Also fungi, algae and other Kingdom Protista organisms Animal Cell outer most part is the plasma membrane Also protozoans (Kingdom Protista)
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  • 32 Cell Wall Functions to protect and support NOT selectively permeable Porous: let anything in Plant cell wall made of cellulose (wood)
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  • 33 Plant Cell Wall
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  • 34 Nucleus Controls all cell activities Contains information to make proteins; all parts of the cell depend on proteins to do its job
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  • 35 Nucleus Contains DNA in strands known as chromatin (chromosomes are chromatin that is condensed and visible during cell reproduction)
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  • 36 Nucleolus Found in the nucleus Organelle that makes ribosomes Ribosomes are sites where proteins are manufactured
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  • 37 Ribosomes Ribosomes are unique because they do not have a membrane around them Found in prokaryotes and eukaryotes Look like pepper on the ER (spaghetti)
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  • 38 Nuclear Membrane Also called Nuclear Envelope Surrounds the nucleus Same composition as the plasma membrane Contains pores to allow large materials to pass out (ribosomes and RNA)
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  • 39 Cytoplasm All the gelatinous material with the organelles inside the cell between the nucleus and the cell membrane Cytosol is that part of the cytoplasm that is liquid
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  • 40 Organelles for Assembly, Transport and Storage Endoplasmic Reticulum (ER) Golgi Apparatus Vacuoles Lysosomes All have phospholipid bilayer membrane structure
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  • 41 Endoplasmic Reticulum (ER) Folded membrane like an accordion for workspace Rough ER contains ribosomes for protein production Smooth ER (No ribosomes) for lipid production Tube-like for transport of materials
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  • 42 Golgi Apparatus Takes protein from the ER and makes it ready to be transported Like UPS, packages it and gives it a destination address
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  • 43 Vacuoles Large central vacuole in plant cells to store water Smaller vacuoles for storage of food, waste, water, enzymes and other substances in both plant and animal cells
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  • 44 Lysosomes Double membrane bound sac containing digestive enzymes Digests food particles, engulfed viruses and bacteria, and worn out cell parts Can fuse with vacuole to digest contents of vacuole
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  • 45 Energy Transformers Chloroplasts Mitochondria Both have phospholipid bilayer membrane structure
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  • 46 Chloroplasts Capture light energy and produce food to be used later Pigment chlorophyll give plants their green color Other plastids store starch, lipids and other pigments
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  • 47 Chloroplasts Double membrane Clear outer Folded inner: thylakoid Stacks of membranes sacs grana and liquid stroma Site of photosynthesis
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  • 48 Mitochondria Break down food to release energy Found in eukaryotes
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  • 49 Mitochondria Double membrane Outer Folded Inner to increase membrane space Some cells need much energy and have hundreds of mitochondria; other cell have few mitochondria because these cells use little energy Site of cellular respiration
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  • 50 Structures for Support and Locomotion Cytoskeleton Cilia Flagella
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  • 51 Cytoskeleton Internal framework in the cell to keep the organelles in place Maintains the cells shape Made of microtubules (hollow) and microfilaments (solid) protein fibers Shown in green
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  • 52 Centrioles Made of groups of microtub