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+ Cellular Transport Bio.1.2.1 Explain how homeostasis is maintained in a cell and within an organism in various environments (including temperature and pH).
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+ What is the cell membrane used for? 1. Controls what enters and exits the cell 2. Maintains an internal balance AKA: Homeostasis 3. Provides protection 4. Provides support
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+ Can you recall the structure of the Cell membrane? Phospholipid Bilayer : A Bicycle has 2 wheels VS Bilayer has two layers!
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+ Phospholipid Bilayer consist of: 1. Phosphate Head (polar)( hydro philic) 2. Fatty Acid Tail (non-polar) ( hydro phobic) 3. Embedded Proteins
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+ Draw a Phosphate head and a fatty acid tail Label: Head Tail Hydrophobic Hydrophilic
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+ Does the Cell membrane allow anything to come into the cell? Selectively permeable: Allows some molecules in and keeps other molecules out http://www.phschool.com/science/biolo gy_place/biocoach/biomembrane1/per meability.html http://www.phschool.com/science/biolo gy_place/biocoach/biomembrane1/per meability.html
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+ 2 Types of Cellular Transport 1.Passive : no energy used by the cell Diffusion Facilitated Diffusion Osmosis (High to Low) 2. Active : Energy used by the cell Protein Pumps Endocytosis Exocytosis (Low to High)
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+ Low to high (so much slower) lots of energy used High to Low (so much faster) No energy used
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+ Passive Transport no energy used molecules move randomly Molecules spread out from an area of high concentration to an area of low concentration. (High Low)
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+ 3 types of Passive Transport 1. Diffusion 2. Facilitative Diffusion 3. Osmosis
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+ Diffusion random movement of particles from an area of high concentration to an area of low concentration. continues until all molecules are evenly spaced
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+ Facilitative Diffusion. Facilitated diffusion: diffusion of specific particles through transport proteins found in the membrane a. Transport Proteins are specific – they “select” only certain molecules to cross the membrane b. Transports larger or charged molecules
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+ Osmosis Osmosis: diffusion of water through a selectively permeable membrane Water moves from high to low concentrations Water is small and there is a lot of it. The cell can not control it’s movement through the cell membrane https://www.youtube.com/watch?v=qK q3hOgC8YE
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+ 3 types of Active Transport Protein Pumps Endocytosis Exocytosis
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+ Active Transport cell uses energy actively moves molecules to where they are needed Movement from an area of low concentration to an area of high concentration
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+ Type of Active Transport Protein Pumps -transport proteins ( needs energy AKA ATP to do work) PUMPS material into the cell
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+ Type of Active Transport Endocytosis: taking large material into a cell Uses energy “cell eating” forms food vacuole & digests food This is how white blood cells eat bacteria https://www.youtube.com/watch?v=Z_mXDvZQ6dU https://www.youtube.com/watch?v=Z_mXDvZQ6dU
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+ Endocytosis
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+ Type of Active Transport Exocytosis : Forces material out of cell in bulk membrane surrounding the material fuses with cell membrane Cell changes shape – uses energy Example: Hormones or wastes released from cell
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+ Cell must maintain their pH This is done by using Buffers :molecules that easily interconvert between acidic and basic forms, donating or accepting protons as conditions change. HOMEOSTASIS
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+ Can you recall Turgor Pressure? The PRESSURE exerted by WATER inside the cell against the CELL WALL
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+ Solutes vs. Solution (solvent) Solution: Mixture of one or more substance (solutes) are distributed evenly in another substances (solvent). WHAT IS THE UNIVERSAL SOLVENT? Solutes: Is mixed into the solvent ( sugar or salt) LETS SEE THIS
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+ Keep in mind SOLUTES SUCK High to Low
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+ LET’S TALK ABOUT HYPER,HYPO AND ISO!
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+ Hypertonic The solution has a higher concentration of solutes 20% and a lower concentration of water than inside the cell. (High solute to Low water)
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+ Hypotonic The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute to High water)
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+ Isotonic The concentration of solutes in the solution is equal to the concentration of solutes inside the cell.
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+
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