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Cell Biology. A Tour of the Cell. Outline. Cell Structure and Organelles Electron micrographs, figures and function Cell Molecular Components. Structure of Animal Cells. Cell Video. Protection and Controlling Entry. Cell Membrane. Cell Membrane Composition.
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Cell Biology A Tour of the Cell
Outline • Cell Structure and Organelles • Electron micrographs, figures and function • Cell Molecular Components
Structure of Animal Cells Cell Video
Protection and Controlling Entry
Cell Membrane Composition • Plasma membrane encloses cell and cell organelles • Made of hydrophobic and hydrophillic components • Semi-permeable and fluid-like • “lipid bilayer”
Cell Membrane Composition • Integral proteins interact with “lipid bilayer” • Passive transport pores and channels • Active transport pumps and carriers • Membrane-linked enzymes, receptors and transducers • Sterols stabilize the lipid bilayer • Cholesterol
Cell Wall • Function: provides support and protection to the cell membrane • Found outside the cell membrane in plant cells • Cellulose is porous, rigid and strong
Cell Organelles • Nucleus Nickname:“The Control Center” Function: holds the DNA Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes Chromatin: loosely coiled DNA (cells not dividing) two types – hetero__ –dark - eu__ - light
Mitochondria • Double membrane • Mitochondrial (maternal) DNA, • replicates independently from the cell • “Power House” of the cell • Food converted into energy • Adenosine triphosphate (ATP) • Consumes Oxygen, produces CO2
Chloroplast Nick name: Sugar Daddies Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment Double membrane structure Unique DNA, replicates independently from the cell
Endoplasmic Reticulum (ER) • Site where cell membrane and exported material is made • Rough ER (+ Ribosomes) • Make proteins to be shipped out • Smooth ER Make lipids to be shipped out
Ribosomes • sites of protein synthesis. • not membrane-bound • consists of a small and larger subunit, • consists of ribosomal RNA (rRNA) and some 50 structural proteins. • Bound ribsosomes make proteins for export, non-bound ribosomes make proteins for internal use • Most plentiful organelle in the cell
Lysosomes: circular, but bigger than ribosomes Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells Intracellular digestion Releases nutrients Breakdown of waste
Autolysis • Self-destruction of damaged cells: • auto = self, lysis = break • lysosome membranes break down • digestive enzymes released • cell decomposes • cellular materials recycle
Golgi Complex/Apparatus Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes
Note the direction of the flow Of the material into the cis and Out the trans.
Vessicles • Peroxisomes • Hydrogen Peroxide generated and degraded to detoxify the cell • Vessicles • Material transport • Vacuole • stores water • Plastids • Leucoplasts, aka amyloplasts store starch, protein or oils. • Chromoplasts store bright colorpigments
Inter mediate filaments Microfilaments Microtubules
Structural proteins for shape and strength • Microfilaments • Thin filaments composed of the protein actin: • provide additional mechanical strength • interact with proteins for consistency • Pairs with thick filaments of myosin for muscle movement • Intermediate • Mid-sized between microfilaments and thick filaments: • durable (collagen) • strengthen cell and maintain shape • stabilize organelles • stabilize cell position
Microtubules • Large, hollow tubes of tubulin protein: • attach to centrosome • strengthen cell and anchor organelles • change cell shape • move vesicles within cell (kinesin and dynein) • form spindle apparatus • Form cilia and flagella
Centrioles in the Centrosome Centrioles form spindle apparatus during cell division Centrosome: cytoplasm surrounding centriole
Cell Adhesion Gycocalyx -vecro-like ogliosaccharides that bind and hold to other cells Tight Junctions - seal/adhere cells together Adherens Junctions - actin filaments that bind and hold cells together Gap Junction -trans-cellular protein channels
Desmosome -proteins the anchor intermediate filaments from neighbouring cells together