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Published byMervyn George Modified over 9 years ago
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Cell Structures
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Cell Structures
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Barriers… Cell Wall Plants & prok. (not animals) Plants & prok. (not animals) Structural (plant support) & protective role Structural (plant support) & protective role Cellulose in plants Cellulose in plants Freely permeable Freely permeable
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Cell walls of onion skin…
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Barriers… Cell Membrane (plasma membrane) In ALL cells Support/protection Regulates movement in/out of: Regulates movement in/out of:WaterNutrients Waste products
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Cell Membrane...
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Barriers… Nuclear Envelope (nuclear membrane) Surrounds nucleus Thousands of pores Material move in/out, incl. RNA
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Nuclear envelope
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Fluids… Cytoplasm (cytosol) Bet. cell mem. and nuclear env., site of most chemical activity Nucleoplasm Semi-fluid medium of nucleus Protoplasm Term used for all substances inside cell
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The Control Center The Nucleus
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The Nucleus… Controls most cell processes Contains Chromatin DNA bound to proteins During cell division, condenses to Chromosomes… Has a Nucleolus Small, dense region Assembly of Ribosomes Nuclear Envelope (or membrane)
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Little Organs assist the cell in conducting reproductive, respiratory, and structural needs Organelles of the cytoplasm
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Cytoskeleton… Protein filaments Maintains cell shape Involved in cell movement
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Cytoskeleton
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Mitochondrion… Uses energy from food Makes high-energy compounds (ATP) needed for Rx elsewhere.
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Ribosomes… Small, made of RNA (is an RNA molecule) Assembly of proteins Free in cytoplasm or attached to Rough ER
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Endoplasmic Reticulum… Large, assists with other organelle movement Two types: Rough ER (RER) Rough ER (RER) ○ Ribosomes stud surface ○ Aids in synthesis and modif. of proteins ○ Found wrapped around nucleus, extending into cytosol Smooth ER (SER) Smooth ER (SER) ○ No ribosomes, attached to distal RER ○ Synthesis of lipids, phospholipids, steroids (Plentiful in testes, ovaries, skin oil glands) (Plentiful in testes, ovaries, skin oil glands)
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Golgi Apparatus… Receives proteins from rough ER Enzymes attach carbs and lipids to the proteins Can store proteins until needed Proteins then sent to final destination (within cell or outside – exocytosis) PACKAGING and SHIPPING
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Golgi Apparatus
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Vacuoles… Saclike structure Stores water, salts, proteins, carbs Can be large in plant cells Helps in plant support by keeping turgor pressure high
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Vacuoles
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Vacuoles Korotnovella, an amoeba. Inside this cell we can see a nucleus near the center with a rather angular dark nucleolus, various food vacuoles, and a clear round contractile vacuole at about 10 o'clock.
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Lysosomes… Filled with enzymes (like H 2 O 2 ) Breaks down lipids, carbs, and proteins from food old organelles debris and harmful invaders
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Video
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Plastid 1: Chloroplasts… In plants, not animals or fungi Uses sunlight to make energy rich food mol. thru photosynthesis (psyn)
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Chloroplasts…
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Chloroplast
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Plastid 2: Leucoplast Sometimes called amyloplast; stores starch (amylose)
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Plastid 3: Chromoplast Stores pigments in plants
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Centrioles Cylindrical; group of microtubules In animal cells, used in cell division As “basal bodies,” form cilia and flagella
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Cell membrane - Structure A phospholipid contains- one head; negatively charged phosphate group that is hydrophilic (water-loving) one head; negatively charged phosphate group that is hydrophilic (water-loving) two tails of fatty acid chains that are hydrophobic (water fearing) two tails of fatty acid chains that are hydrophobic (water fearing)
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The Cell Membrane Made of a phospholipid bilayer regulates what passes in/out Supports and protects Selectively permeable – only certain things pass through. 5 nm thick
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Cell membrane features The fluid mosaic model fluid in nature cell mobility Within mem. are various proteins for : enzyme activity, cell attachment, communicating with other cells, Trans. of substances in and out
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