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Transcript
•Cellular Organelles •Cellular Transport History •1665 – Robert Hooke – observation of cork cells •1833 – Robert Brown – nucleus discovery Robert Hooke’s work • Cell Theory • Schleidan, Schwann, Virchow –All organisms made up of one or more cells –Cells are the basic unit of anatomy and physiology –New cells come from existing cells by reproduction 2 basic types of cells • prokaryotic • eukaryotic Prokaryotic Cells • prokaryotic – Pro = before/ kary = nucleus – Oldest known form of life – Very primitive – Small (about 1 micrometer) – No membrane bound organelles – Ex. bacteria Eukaryotic Cells • Eu = true • Have membrane bound organelles and a nucleus • Large (20 – 50) micrometers • Specialized organelles carry out cell functions Two main types of eukaryotic cells • Plant Cells • Animal Cells Plant cell Animal Cell • Anatomy and Physiology • Cellular organelles found within eukaryotic cells The Nucleus • Contains DNA • Surrounded by nuclear membrane • Brain of the cell Interior of Nucleus • Inside are long thin strands of chromatin and nucleic acid Anatomy of nucleus • Nucleolus – makes and stores RNA and ribosomes • Nuclear membrane – selectively permeable Electron Micrograph of Nucleus • Ribosomes • Site of protein synthesis – free floating or attached to rough ER Mitochondria • “Power house” of the cell • Enzymes release energy Two membranes • Inner membrane – “cristae” – folded like shelves to increase surface area • Outer – separates organelle from cytoplasm Electron Micrograph of Mitochondria • Endoplasmic Reticulum • Transport of protein and lipids Two types • Rough ER • Smooth ER Rough Endoplasmic Reticulum • Site of protein synthesis • Transport to smooth ER Smooth ER • No ribosomes • Forms vesicle and transports to Golgi apparatus Golgi Apparatus • Discovered by Camillio Golgi Function • Proteins vesicles enter • Carbohydrates are added or material is concentrated (H2O removal) • New membrane formed and secreted Lysosomes • Recycling centers • Breaks down worn and damaged cell structures • Unaffected by digestive enzyme inside Lysosomes •Common in animals Vacuoles Usually fluid filled structures Storage 1. Animals – cytoplasm, temporary storage site, small 2. Plants – very large, hold water 3. Unicellular – digestion, storage, contractile vacuoles remove water and waste Cytoskeleton • Miniature internal support system in cytoplasm • Composed of microtubules • Give cells shape Centrioles • Mostly in animals • Near nucleus • Composed of microtubules • Cellular reproduction Plastids • Plant cells only • Three types –Chloroplast –Leucoplast –Chromoplast Chloroplast • Most common • Green pigment – chlorophyll • Glucose is made 1. Chloroplast 2. Leucoplast – storage or proteins, lipids, starches 3. Chromoplast – yellow, red, and orange pigments • http://biology.about.com/library/weekly /aa033000a.htm • www.virtualcell.com Plasma Membrane •Protective Barrier •Selectively Permeable Structure of membrane • Double layer of phospholipid molecules and proteins • Constant motion Function • Prevents large particles from entering • Permits molecules like O2, CO2, and H2O Cell Wall • Composed of cellulose • Gives shape and rigidity 3 parts • Primary cell wall – soft and flexible • Secondary cell wall – develops when cell reaches full size, gives strength • Middle Lamella – jellylike polysachharide material called pectin Part II Cellular Transport Cellular Transport • Regulated by the cell membrane • Dependent on the type of solution and concentration gradient 3 Types of Solutions • Hypotonic – lower concentration of solutes than solvent • Hypertonic – higher concentration of solutes than solvent • Isotonic – solution same on both sides of membrane Examples • Hypotonic – distilled water + red blood cells • Hypertonic – salt water + red blood cells • Isotonic – animal red blood cells in 80% water If the cell is in…. • Distilled water….the cell will burst • Salt water…the cell will shrink 2 Types of Cellular Transport • Passive Transport – NO energy required to get materials across concentration gradient • Active Transport – energy required 3 types of Passive transport • Movement from high concentration to low concentration –Diffusion –Facilitated diffusion –Osmosis Diffusion • Movement of molecules in gases and liquids from high concentration to low • Ex. Food coloring in water, perfume in air Facilitated diffusion • Carrier molecules carry other molecules across concentration gradient –Very few molecules can do this –Proteins carry glucose molecules into red blood cells Osmosis • Movement of molecules in liquids by going across a membrane • Homeostasis • For a cell to survive, it must be able to maintain the process of homeostasis, maintenance of constant internal environment, despite external change Active Transport • Energy is required to move materials against the concentration gradient, from low concentration to high • 2 types –Endocytosis –Exocytosis Endocytosis • Movement “inside” cell –Pinocytosis – cell drinking –Phagocytosis – food particles •Ex. Amoeba engulfing food particles encased in vacuoles Exocytosis • “outside” of cell –Release of large molecules and waste products, membrane breaks open and vacuole is released • • •