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CYTOLOGY. THE STUDY OF CELLS - STRUCTURE. GENERAL. Cell = Smallest Living Unit Produced by Cell Division or Fertilization Surrounded by Interstitial / Extracellular Fluid Components: Plasma (Cell) Membrane Cytoplasm Nucleus. THE PLASMA MEMBRANE. Structure Phospholipid bilayer
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CYTOLOGY THE STUDY OF CELLS - STRUCTURE
GENERAL • Cell = Smallest Living Unit • Produced by Cell Division or Fertilization • Surrounded by Interstitial / Extracellular Fluid • Components: • Plasma (Cell) Membrane • Cytoplasm • Nucleus
THE PLASMA MEMBRANE • Structure • Phospholipid bilayer • self-orienting, reseals • hydrophilic heads (face outward) • hydrophobic tails (face inward) • Proteins (floating or anchored) • Cholesterol (keeps it “fluid”)
THE PLASMA MEMBRANE • Functions: • Physical Barrier (Selective!) • Fat-soluble do pass through • Water-soluble don’t • Proteins: • Channels or Carriers (transport) • Enzymes (chemical reactions) • Receptor sites (“docking” of molecules) • Anchors
CYTOPLASM • Material Between Plasma Membrane & Nucleus • Components • Cytosol (fluid with solutes) • Cytoplasmic Organelles • Inclusions (stored materials) • Site of chemical reactions
NUCLEUS • Organelle • Double Nuclear Membrane with Pores • DNA – Instructions for making proteins • Chromatin - loose; protein synthesis • Chromosomes - dense, rod-like; cell division • Nucleolus • Assembly of ribosomes
CYTOPLASMIC ORGANELLES • Mitochondria • ATP synthesis (cellular energy) • Self-replicating • Contains DNA
CYTOPLASMIC ORGANELLES • Ribosomes • Site of Protein Synthesis • Free or Attached • Rough Endoplasmic Reticulum • Membrane synthesis • Proteins made for export
CYTOPLASMIC ORGANELLES • Smooth ER • Lipid synthesis & breakdown • Detoxification
CYTOPLASMIC ORGANELLES • Golgi Apparatus Prepares proteins for export Makes lysosomes Packages material to add to plasma membrane
CYTOPLASMIC ORGANELLES • Lysosomes • Digestion within the cell • Defense • Recycle worn-out cells • Peroxisomes • Detoxify • Alcohol • Formaldehyde • Free Radicals
CYTOPLASMIC ORGANELLES • Cytoskeleton • Proteins • Support & Shape • Movement inside cell • Centrioles • Form Spindle • Form base of cilia & flagella
CYTOPLASMIC ORGANELLES • Cilia – short, numerous, move substances over free surfaces • Flagella – long, singular, move cell • Microvilli – thin folds of cell membrane, increase surface area to maximize absorption
Cytoplasmic Organelles • Proteosomes • Ring of stacked proteins around central core • Break-up undesirable proteins • Vaults • Ribonucleoprotein (proteins + RNA) • May be involved in transport between nucleus & cytoplasm?