3.3-3.4 study guide – Flashcards
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Cell membrane
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The plasma membrane forms a boundary between a cell and the outside enviornment passage materials
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Phospholipid
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Molecule composed of three basic parts
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Fluid mosaic model
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Describes the arrangment of the molecule that make up the cell membrane
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Selective permeability
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Allows some but not all materials to cross
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Receptor
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Protein that detects a signal molecule and preforms an action in response
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Passive transport
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The movement of molecule across a cell membrane w/out energy imput- from the cell
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Diffusion
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The movemnt of molecules in a fluid or gas from a region of higher con to lower
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Concentration gradient
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The difference in the concentarion of a substance from one location to another
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Osmosis
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Move across a semipermeable membrane from an area of highee water con to a lower
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Isotonic
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A cell if it has the same comcentation of dissolved particles as the cell
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Hypertonic
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Higher concentration of dissolved particles than a cell
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Hypotonic
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Solution has a lower concentration of dissolved particles than a cell
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Facilitated diffusion
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The diffusion of molecules acorss a membrane through transporting proteins to make it easier
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What are cell membranes made of ?
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Double layer of phosphlipids interspread w/ a variety of other molecules
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3 molecules inside the cell membrane
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Proteins , cholesterol , and carbohydrates
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What is selective permeability
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Allows some molecules to pass freely but not all
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How are chemical signals transferred across the membrane ?
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Receptors
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Where are receptors found?
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Inside the cell or within the cell membrane
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Cell membranes are what?
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Selective barriers
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What is one way cells move molecules across their membranes
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Passive transport
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3 types of passive transport
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Diffusion, osmosis , facilitated diffusion
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What part of a phospholipid is charged , or polar ?
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The head
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Which part of the phospholipid is non polar?
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Tail
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What type of molecules interact with water ?
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Polar
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Where does a cell membrane come into contact with water
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Phosphate head
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Why do the phospholipids surrounding the cell form a bilayer
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Polarity , non polar tails attracted each other
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Cholesterol
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Helps maintain flexability
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Proteins
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Transport certain materials
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Carbohydrates
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Cell to cell recongition
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In what way is a membrane fluid ?
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Move side to side
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A receptor does what?
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Detects a signal molecule and carries action in response
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Fluid mosaic model
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Describes all arrangement of molecules in a flexable layer
