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Cell Membrane Passive Vs Active Transport
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Cell Unit Outline Diffusion and osmosis Active vs Passive transport Mitosis and meiosis
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ACOS # 2 Describe cell processes necessary for achieving homeostasis, including active and passive transport, osmosis, diffusion, exocytosis and endosytosis –Identify functions of carbohydrates, lipids, proteins, and nucleic acids –Compare reactions of plant and animal cells in isotonic, hypotonic and hypertonic solutions
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ACOS # 2 –Explain how surface area, cell size, temperature, light an pH affect cellular activities –Apply the concept of fluid pressure to biological systems; examples – blood pressure, turgor pressure, bends, strokes
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ACOS # 2 – Terms Active transport – when the cell must use energy to move substances in or out Bends – decompression sickness; caused by nitrogen gas under pressure Concentration gradient – when there is a greater amount (of molecules) in one place than there is in another
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ACOS # 2 – Terms Endocytosis – type of active transport when a cell brings large materials inside Exocytosis – type of active transport when cells move materials to the outside Diffusion – type of passive transport when molecule ‘spread out’ Homeostasis – steady state; the process of maintaining correct conditions for life
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ACOS # 2 – Terms Hypertonic – a concentrated solution Hypotonic – a less concentrated solution Isotonic – two solutions are in equal concentration Osmosis – type of passive transport; when water diffuses down its concentration gradient
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ACOS # 2 – Terms Passive transport – when the cell can use the energy of the molecules to move materials in or out and not its own energy pH – unit measuring acidity (blood) Surface area – the ratio of outside of a cell compared to the total volume of the cell
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ACOS # 2 – Terms Stroke – rupture of a blood vessel (usually from high blood pressure) Turgor – pressure created by water in the water vacuole of plant cells
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Cell Membrane Cell have to move materials in or out What do they move in - ? What do they move out - ? What structure controls what gets in or out?
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Cell Membrane Controls what materials enter or exit the cell
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Passive Transport PASSIVE TRANSPORTPASSIVE TRANSPORT – the cell does not have to spend its energy for molecules to get in/out Molecules are in constant motion The energy from the motion may be enough to let some molecules ‘leak’ through the membrane Molecules ‘want’ to ‘spread out’
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Concentration Gradient Molecules may be closer together in one area than they are in another The difference between the concentration of molecules in one area vs the other area is called a: CONCENTRATION GRADIENTCONCENTRATION GRADIENT
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Diffusion Diffusion – when molecules move from where they are close together to spread apart CONCENTRATION GRADIENTWhenever there is a CONCENTRATION GRADIENT, molecules will diffuse The molecules will try to spread out Molecules move from an area of high concentration to an area of low concentration
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Diffusion
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Types of Passive Transport DiffusionDiffusion – molecules ‘spread out’; move from an area of high concentration to an area of lower concentration Small molecules diffuse through the membrane easily; oxygencarbon dioxide –Gases like oxygen and carbon dioxide
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Diffusion CONCENTRATION GRADIENTMolecules move from an area of high concentration into the area of lower concentration “down the CONCENTRATION GRADIENT” OxygenOxygen diffuses into blood cells from the lungs Carbon dioxideCarbon dioxide diffuses from blood to the lungs
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Alveoli
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Lots of CO 2 No O 2 Oxygen CO 2 ALVEOLUS
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Lots of CO 2 No O 2 Oxygen CO 2
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Lots of CO 2 No O 2 Oxygen CO 2 Oxygen Lots of O 2 ; No CO 2
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Diffusion In Your Lungs Carbon dioxideDIFFUSES CONCENTRATION GRADIENTCarbon dioxide (CO 2 ) DIFFUSES down its CONCENTRATION GRADIENT out of the red blood cells OxygenDIFFUSES CONCENTRATION GRADIENTOxygen DIFFUSES down its CONCENTRATION GRADIENT into the red blood cells
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Diffusion In Your Body In your body, all your body cells (muscles, skin, stomach, nerves) produce carbon dioxide and use up oxygen Carbon dioxideCarbon dioxide DIFFUSES out of the body cells and into the blood cells OxygenOxygen DIFFUSES from blood cells into body cells
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CO 2 Oxygen Smoking prevents diffusion
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Passive Transport - Diffusion The movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration PASSIVE TRANSPORT –A type of PASSIVE TRANSPORT because the molecules have enough energy to move across the membrane
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Passive Transport - Osmosis A type of diffusion WaterWater molecules move down their concentration gradient from an area where there is more water to the area where there is less water
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Osmosis solutionCells are a solution of sugars, proteins, minerals, salts, etc. Cells are surrounded by a solution The amount of water in the cell compared to the amount of water outside of the cell is the concentration gradient
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Solutions Made of two parts: SoluteSolute = substance that gets dissolved; ex. Sugar, salts, minerals; tea, kool-aid SolventSolvent = substance that does the dissolving, usually water CONCENTRATIONThe amount of sugar (solute) in the water is the CONCENTRATION
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Osmosis Three terms are used to describe the solution inside the cell compared to the solution outside the cell: –Hypertonic –Hypotonic –Isotonic
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Osmosis HypertonicMOREHypertonic = a solution that has MORE solutes than the other solution. Hyper = higher HypotonicLESSHypotonic = a solution that has LESS solutes than the other solution. Hypo - low IsotonicEQUALIsotonic = solutions that have EQUAL amounts of solutes
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1% ISOTONIC
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0% The cell is HYPERTONIC HYPOTONIC The solution is HYPOTONIC Water moves from the lower number into the higher number
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1% 3% HYPOTONIC The cell is HYPOTONIC HYPERTONIC The solution is HYPERTONIC Water moves from the lower number into the higher number
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1% Water always moves from the area of high WATER concentration into the area of low WATER concentration Equilibrium
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1% 3% Solution is____________ Size of the cell will… Cell = 1% salts 99% water Solution = 3% salts 97% water
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1% 0% Solution is ______________ Cell = 1% salts 99% water Solution – 0% salts 100 % water Cell will ………
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Osmosis HYPOtonic HYPERtonicWater will move from HYPOtonic into HYPERtonic
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1% 3%
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1% 2%
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Hypertonic solution
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Plasmolysis
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Hypotonic solution Turgor pressure = water pressure placed on plant cell walls
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1% 0%
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1%
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3%
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Osmosis
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3%3% 1% salt Salt water fish
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0% 1% Fresh water fish
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0% -freshwater 1% salt
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0% salt 0%
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3% salt water 1%
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3% salt water 3% Osmosis
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Passive Transport- Facilitated Diffusion Some molecules are too big and need ‘help’ to fit through the membrane –Ex. Glucose A special molecule embedded in the membrane acts as a ‘channel’ to let glucose in INSULININSULIN
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Insulin Transport protein Insulin Glucose Insulin
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Insulin Glucose
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Insulin
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Insulin
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Passive Transport: Review no energyCell spends no energy for molecules to move inside 3 types: –Diffusion –Osmosis –Facilitated diffusion
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Active Transport Energy Cell Has to Use Energy To Move Substances Across The Membrane
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Active Transport Why does the Cell have to use its own energy? AGAINST 1.Must move particles AGAINST the concentration gradient LARGE 2.Particles are too LARGE
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Types of Active Transport EndocytosisEndocytosis ExocytosisExocytosis
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Endocytosis Large particles brought into the cell TOO BIGTOO BIG Cell membrane ‘pinches’ in
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Endocytosis/Exocytosis
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Phagocytosis Amoeba
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Endocytosis
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Phagocytosis
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Exocytosis outsideLarge particles are moved to outside of the cell Opposite of endocytosis Two reasons: 1.Excretion 1.Excretion – removal of wastes 2.Secretion INSULIN 2.Secretion – substance used by another cell (INSULIN)
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Exocytosis
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Cell Transport: Review PassivePassive Diffusion Osmosis Facilitated diffusion ActiveActive Pumps Endocytosis Exocytosis
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