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On right hand side of a clean page write:. 1. Learning goal,. 2
On right hand side of a clean page write: 1. Learning goal, 2. Critical question, and 3. Answer the Warm Up Question: Does a cell use active or passive transport to move molecules across its membrane and why? (Give examples)
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Functions, & Structures of, Cell Membrane & Movement Across it
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Cell (plasma) membrane
Cells need an inside & an outside… separate cell from its environment cell membrane is the boundary IN food - sugars - proteins - fats salts O2 H2O OUT waste - ammonia - salts - CO2 - H2O products - proteins cell needs materials in & products or waste out
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Remember: oil & water don’t mix!!
Building a membrane How do you build a barrier that keeps the watery contents of the cell separate from the watery environment? FATS LIPIDS Remember: oil & water don’t mix!! What substance do you know that doesn’t mix with water?
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Functions of Plasma Membrane
The Plasma Membrane 5/20/2018 Functions of Plasma Membrane Protective barrier Helps cell maintain homeostasis Controls what enters Controls what leaves Provides anchoring site for cytoskeleton G. Podgorski, Biol. 1010
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Structures of Cell Membrane
The Plasma Membrane 5/20/2018 Structures of Cell Membrane copyright cmassengale G. Podgorski, Biol. 1010
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Structures of Cell Membrane
Phospholipids - special kind of lipid that has a polar head and non-polar tails Cell Membrane is double layer phospholipid bilayer “attracted to water” phosphate inside cell outside cell lipid “repelled by water”
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Structure of Cell: Phospholipid Bilayer
The Plasma Membrane 5/20/2018 Structure of Cell: Phospholipid Bilayer Polar heads are hydrophilic “water loving” Nonpolar tails are hydrophobic “water fearing” Makes membrane “Selective” in what crosses G. Podgorski, Biol. 1010
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Structure of Cell: Phospholipid Bilayer
The Phospholipid Bilayer is a semi-permeable membrane because The membrane allows some materials — but not all — to pass through the membrane only some material can get in or out So what needs to get across the membrane? sugar lipids aa O2 H2O salt waste
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2 Ways of Crossing Cell Membrane
Structure of Cell: Phospholipid Bilayer 2 Ways of Crossing Cell Membrane Solubility Material that is soluble in lipids can pass easily Fats and oils can pass directly through Small Particles lipid inside cell outside cell Are these materials polar or non-polar?
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2 Ways of Crossing cell membrane
Structure of Cell: Phospholipid Bilayer 2 Ways of Crossing cell membrane Small Particles Small molecules can easily pass through the spaces of the cell membrane O2 CO2 H2O Solubility ions Hydrophilic molecules & Proteins cannot move through the membrane on its own. lipid inside cell outside cell salt waste water but… what about other stuff? sugar aa
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Protein Channels Structure of Cell: Are“doors” through the membrane
protein channels allow insoluble molecules in & out Channels are specific to the molecules they let in & out salt, sugar, amino acid, certain waste, etc. inside cell aa sugar salt outside cell waste
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Movement through the channel
Why do molecules move through membrane if you give them a channel? HIGH ? 1 LOW ?
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Types of Transport (Movement) Across Cell Membranes
The Plasma Membrane 5/20/2018 Types of Transport (Movement) Across Cell Membranes 1. Passive Transport 2. Active Transport - Simple Diffusion - Facilitated Diffusion copyright cmassengale G. Podgorski, Biol. 1010
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Molecules move from high to low
Simple Diffusion: Passive Molecules move from high to low Diffusion: movement of molecules from an area of HIGH to LOW concentration across a semi permeable membrane no energy needed No protein channel needed diffusion of water diffusion Can cross over a membrane osmosis
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Simple Diffusion: Practice
Molecules Move from HIGH to LOW fat fat fat Which way will fat move? inside cell fat fat fat LOW HIGH fat outside cell fat fat fat fat fat fat fat
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Facilitated Diffusion: Practice
Facilitative Transport: Passive Facilitated Diffusion: Practice Move from HIGH to LOW through a channel sugar sugar sugar sugar inside cell sugar sugar LOW Which way will sugar move? HIGH outside cell sugar sugar sugar sugar sugar sugar sugar
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Simple vs. facilitated diffusion
Both Passive!! This means they both do or don’t require energy? Simple vs. facilitated diffusion simple diffusion facilitated diffusion lipid inside cell outside cell inside cell outside cell NA+ protein channel lipid NA+ lipid NA+ lipid lipid NA+ NA+ NA+
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facilitated diffusion
WAIT!!! Brainstorm with your groups the answer to the following question. If simple diffusion & facilitated transport don’t require energy, why do organisms get tired? Is there another type of transport that doesn’t occur naturally, and therefore makes us use energy? simple diffusion facilitated diffusion inside cell outside cell lipid inside cell outside cell NA+ protein channel lipid NA+ lipid NA+ lipid lipid NA+ NA+ NA+
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Active transport Cells may need molecules to move against concentration gradient from LOW to HIGH using energy protein pump requires energy ATP Plants have nitrate & phosphate pumps in their roots. Why? Nitrate for amino acids Phosphate for DNA & membranes Not coincidentally these are the main constituents of fertilizer. ATP
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Act. Trans. Ex: Animals have Na+ / K+ pump in their brain.
The Plasma Membrane 5/20/2018 Act. Trans. Ex: Animals have Na+ / K+ pump in their brain. Ex: Sodium Potassium Pump 3 Na+ in for every 2 K+ pumped out. This creates a concentration gradients that requires your body to use energy to overcome. Therefore: 1. You need energy! (food) 2. You get tired! Plants have nitrate & phosphate pumps in their roots. Why? Nitrate for amino acids Phosphate for DNA & membranes Not coincidentally these are the main constituents of fertilizer. copyright cmassengale G. Podgorski, Biol. 1010
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Exit Ticket Draw & Label the Transport Summary Diagram
simple diffusion facilitated diffusion WORD BANK Active Transport Passive Transport Simple Diffusion Facilitated Diffusion Requires Energy ATP active transport Requires Energy Requires Energy
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Critical Question Explain what happens to the cells in a saltwater fish if you placed it into a fresh water tank.
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Osmosis: Movement of Water Across Cell Membrane
Warm Up: Label the diagram below with its correct vocabulary word – Solution 4. doing dissolving 2. Solvent 5. being dissolved 3. Solute
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Which direction do you think the water will move in diagram 1?
Is Osmosis passive or active? Osmosis Is it facilitated or simple diffusion? Brainstorm!! Which direction do you think the water will move in diagram 1? What do you think will happen to the yellow circle’s size? Water’s properties are unique, so we talk about water separately! Osmosis diffusion of water from HIGH concentration of H20 (low solute) to LOW concentration of H20 (high solute) Label the yellow circles 1 & 2 - high concentration low solute or low concentration high solute
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Types of Solutions Hypertonic Hypotonic
When water leaves the cell because the Solution has a: High Concentration solute Less water When water enters the cell because the Solution has a: Low Concentration solute More water
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Equal amount of molecules leaving and entering the cell
Keeping water balance Cell survival depends on balancing water uptake & water loss Equal amount of molecules leaving and entering the cell Isotonic Hypotonic Hypertonic
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Keeping right amount of water in cell
1 Keeping right amount of water in cell Hypotonic a cell in fresh water high concentration (more) of water around cell cell gains water example: Paramecium problem: cells gain water, swell & can burst water continually enters Paramecium cell solution: contractile vacuole pumps water out of cell KABOOM! freshwater No problem, here
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Keeping right amount of water in cell
2 Keeping right amount of water in cell Hypertonic a cell in salt water Less / low concentration of water around cell cell loses water example: shellfish problem: cell loses water in plants: plasmolysis in animals: shrinking cell solution: take up water I’m shrinking, I’m shrinking! saltwater I will survive!
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Keeping right amount of water in cell
3 Keeping right amount of water in cell Isotonic no difference in concentration of water between cell & environment cell in equilibrium example: blood problem: none water flows across membrane equally, in both directions volume of cell doesn’t change That’s better! balanced I could be better…
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Appling A young woman decides to go for a hike in Yellowstone National Park on a summer day. She brings: a water bottle, protein bar, hat, some sunscreen and bear repellant. Before her hike, she has a very good breakfast including eggs, oatmeal, fruit, and orange juice. At the beginning the 9 am hike, the day is cool and she’s wearing shorts, a t-shirt, and a light jacket. By noon, she has hiked 5 miles, it is 95 degrees, and very sunny. Describe what cellular processes are occurring to the woman during the day. What occurs inside her body after eating breakfast? What occurs inside her body as she starts her hike? What occurs inside her body as the day warms, and how might she respond to this? At noon, what may be occurring at a cellular and body level, and why? Within your group, answer the questions, brainstorm, and create a list of what may be occurring at both the cellular & body level for this woman. Create your list in your Engage Student Handout. Once your group has completed your list, raise your hand.
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