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Cell Transport
Question | Answer |
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What is passive transport? | The diffusion of a substance across a selectively permeable membrane, such as a cell membrane. |
What is diffusion? | Movement without added energy found in solutions such as living organisms. The the molecules (or ions) of a substance spread out evenly in the space they occupy. |
What is concentration? What is a concentration gradient? | Concentration refers to the number of molecules of a substance in a given volume. A concentration gradient is an unequal concentration from one region to another |
In the absence of other factors, how do molecules diffuse? | Down their concentration gradient. High concentration to low concentration. |
When does diffusion end? | When equilibrium is reached. This becomes a dynamic equilibrium. |
What is osmosis? | A type of diffusion in which only water moves. In osmosis, water molecules diffuse across a selectively permeable membrane from an area of high concentration of water molecules to an area of low concentration of water molecules. |
What is facilitated diffusion? | A type of diffusion that allows polar substances like glucose/ions such as sodium and chloride ions to passively move in and out of cells. |
What do membrane proteins help with? | Facilitated diffusion. |
What is active transport? | Requires cellular energy for solutes to move across the cellular membrane. It uses ATP to provide energy for this movement. |
What does homeostasis require? | Cells actively transport molecules in and out of the cell to achieve and maintain this balance. This is to maintain their internal conditions. |
What pump is important for animal cells? | Sodium-potassium pump. Pumps 3 sodium ions out of the cell and 2 potassium ions into the cell for each cycle of the pump. |
What is endocytosis? | A form of transport that uses ATP and brings large substances into a cell. |
What is exocytosis? | This process is used to move substances out of a cell. |
What does passive transport include? | Diffusion, osmosis, and facilitated diffusion. |