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Presentation1 osmosis and diffusion
The cell membrane is composed of phospholipids, cholesterol, and proteins. It ranges from 7.5-10 nm thick and is only visible under an electron microscope. The cell membrane has several functions including being selectively permeable, acting as a physical barrier, allowing communication between cells, and establishing connections between cells. Transport across the cell membrane can occur through passive transport mechanisms like simple diffusion, facilitated diffusion, and osmosis. Active transport requires energy and moves molecules against their concentration gradient using carrier proteins like sodium-potassium pumps and proton pumps. Vesicular transport uses endocytosis and exocytosis to move larger molecules and vesicles across the membrane.
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Presentation1 osmosis and diffusion
- 1. OSMOSIS AND DIFUSSION OF THECELL MEMBRANE
- 2. CHARACTERISTIC OF CELL MEMBRANE Composed of phospholipid, cholesterol, proteins & chains of oligosaccharides Range of thickness : 7.5 nm – 10 nm Visible only in the electron microscope
- 4. STRUCTURE OF CELL MEMBRANE
- 5. FUNCTIONS OF CELLMEMBRANE Selective Permeability • Size, charge, chemical properties of atoms / molecules determine whether the success in getting through the membrane Physical Barrier • Separates substances inside and outside of the cell
- 6. Act As Communicator • Communication between cells & its environment can occur because it contains receptors that recognize & respond to molecular signals Allows Intercellular Connection • Establish a flexible boundary, protects cellular contents and also supports cell structure
- 7. Transport Across The Cell Membrane Passive Active Transport Vesicle Transport Transport Simple Facilitated Primary Secondary Diffusion Osmosis Endocytosis Exocytosis Diffusion
- 8. SIMPLE AND FACILITATEDDIFFUSION
- 9. Passive transport Goes down the concentration gradient From high concentration to low concentration of solute Does not require energy (ATP)
- 10. SIMPLE DIFFUSION ACROSSA PLASMA MEMBRANE Movement of small molecule through phospholipid bilayer. Lipid soluble molecule due to hydrophobic characteristic of the bilayer.
- 12. FACILITATED DIFFUSION ACROSSA PLASMA MEMBRANE Diffusion of large molecules Requires carrier protein Each carrier protein is specific for one molecule Example – Potassium diffusion.
- 13. Facilitated Diffusion ofPotassium ions through a Gated K + Channel
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- 18. The movement of substances across the plasma membrane against the concentration gradient Molecules or ions move from a region of lower concentration to higher concentration Requires the use of both carrier protein and cellular energy to transport molecules Carrier protein involved in active transport are often called pumps The most known pumps is Sodium-Potassium pumps
- 19. Na-K pumps Primary Proton pumps Active Transport Na-glucose co-transport Secondary Na-Ca exchange
- 20. PRIMARY ACTIVE TRANSPORT SODIUM-POTASSIUM PUMP PROTON PUMP
- 23. Secondary active transport SODIUM-GLUCOSE CO- TRANSPORTER SODIUM-CALCIUM EXCHANGER
- 26. VESICULAR TRANSPORT A meansfor transport of large sized molecules (e.g. proteins) across cell membrane. It represents a specialized function of cell membrane. Requires energy. 2 types;
- 27. ENDOCYTOSIS Divided into 3parts: 1.Phagocytosis -cell eating (uptake of large molecules) 2.Pinocytosis -cell drinking (uptake of solutes) 3.Receptor-mediated -cytoplasm membrane folds inwards and form coated pits.
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- 31. EXOCYTOSIS The excretionof waste material from the cell to its outer environment. Large waste product which requires the formation of vesicles Molecules excreted includes: Cell Debris Waste products Membrane proteins + lipids which are bound to become part of the actual membrane
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Editor's Notes
- #27 Vesicular transporti.e the transport of macromolecules involving vesicles.Most cells use endo and exo to ingest and secrete macromolecules because most of the important subs are large polar molecules and thus arent able to pass through the membrane by the previously discussed methods.
- #28 Why do cells need endocytosis mechanism? Because most substances are important to them are: polar consist of big moleculesPHAGOCYTOSISThe process by which cells ingest large objects, (such as cells which have undergone apoptosis, bacteria, or viruses). The membrane folds around the object, and the object is sealed off into a large vacuole; known as a phagosome.PINOCYTOSISThis process is concerned with the uptake of solutes and single molecules such as proteins.The membrane folds around the liquid, and the liquid is sealed off into a large vacuole; known as a pinocytic vesicles.RECEPTOR MEDIATED ENDOCYTOSISThe process by which cells internalize molecules (endocytosis) into a cell. by the inward budding of plasma membrane vesicles containing proteins.with receptor sites, specific to the molecules being internalized.The cytoplasm membrane folds inward to form clathrin-coated pits. These inward budding vesicles bud to form cytoplasmic vesicles.
- #32 In exo the contents of the vesicle are released out of the cell to the extracellular environmentLikewise to endocytosis it requires the formation of vesicles in order to excrete the macromolecules out of the cell.