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Cell Transport Study Guide, L4

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Define homeostasis
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Keeping a stable internal environment despite changes in the outside environment.
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What is the function of the cell membrane?
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Acts like a boundary for the cell
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What is the cell membrane made from?
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phospholipid bi-layer
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Selectively/semi-permeable
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Some materials can leave or enter through a membrane; some can’t
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Is the cell membrane selectively permeable or not?
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It is; it allows a small selection of molecules in and out.
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What is diffusion?
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The movement of molecules from an area of high concentration to an area of low concentration without the use of energy
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What does \”reach a state of equilibrium\” mean?
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The number of a particular type or types of molecules is even on both sides.
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When a cell reaches a state of equilibrium, does the movement of molecules through the cell membrane stop?
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No, it continues.
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What is osmosis?
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The movement of WATER from an area of high water concentration to an area of low water concentration without the use of energy.
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What does \”passive\” mean when used in cell transport?
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The movement of molecules into and out of cells does NOT require energy.
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What are two types of passive transport?
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Osmosis and diffusion
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What is something you can do to show the movement of molecules through a membrane?
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Draw and label a container that contains a cell. Label the solute concentration in and out of the cell. Draw arrows to indicate movement of water.
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True or false: Water surrounding or in the cell will always move towards the area of greater concentration of SOLUTE.
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True
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What happens when a cell with a low concentration of a a solute, example salt, enters an environment with a higher concentration of the solute?
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Remember to draw the two concentrations. Water will leave the cell and move towards the area of higher concentration of solute. The cell will shrivel up.
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What happens when a cell with a high concentration of a solute, example salt, enters an environment with a lower concentration of the solute?
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Water will move through the cell membrane towards the cell’s high concentration of solute. The cell will swell.
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What happens when the cell’s concentration of a solute equals the concentration of a solute in the environment?
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Water doesn’t need to move. The cell is in a state of equilibrium with its environment.
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hypertonic
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more concentration ofsolute
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hypotonic
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less concentration of solute
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isotonic
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equal concentration of solute
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What is active transport?
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The movement of molecules from an area of low concentration to an area of high concentration with the use of energy.
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Does active transport require energy?
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Yes.
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Does osmosis require energy?
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No
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Does diffusion require energy?
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No
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What are 3 types of active transport?
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Cell membrane pumps Endocytosis Exocytosis
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What is endocytosis?
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Cell brings large molecules IN by pinching off part of the cell membrane allowing the molecules to enter. Molecules eNter.
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What is exocytosis?
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Cell forces large molecules OUT of the cell by putting the waste or unwanted molecule in a vesicle that can go through the cell membrane. Molecules (in a vesicle) EXit.
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What are the 3 parts to the cell theory?
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1. All cells come from other cells 2. The cell is the basic unit of structure and function 3. All living things are made of cells
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What are the four things found in ALL cells?
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Cytoplasm, ribosomes, cell membrane and genetic material such as DNA
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What are the two major types of cells?
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Eukaryotic and prokaryotic
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What types of organisms belong to the two types of cells?
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Eukaryotic – bacteria Prokaryotic – plants, animals, protists and fungi