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Bio-Ch.5 (5-1,5-2)
Homeostasis and Transport
| Question | Answer |
|---|---|
| The movement of substances that cross the cell membrane without any input of energy by the cell | passive transport |
| the movement of molecules from an era of higher concentration to an area of lower concentration. The simplest type of passive transport. | diffusion |
| the difference in the concentration of molecules across a space | concentration gradient |
| example of diffusion | Adding a sugar cube to a beaker of water. Sugar cube sinks to the bottom . The concentration of sugar is greater at the bottom than the top. As cube dissolves, sugar begin to diffuse slowly through the water, moving from the bottom to the top. |
| when the concentration of the molecules of a substance is the same throughout a space | equilibrium |
| How is equilibrium maintained? | Equilibrium is maintained by the random movements of molecules in many directions. |
| the process by which water molecules diffuse across a cell membrane from an area of higher concentration to an area of lower concentration | osmosis |
| Why does osmosis not require cells to expend energy? | Osmosis does not require cells to expend energy because water moves down its concentration gradient. |
| What does the net direction of osmosis depend on? | The net direction of osmosis depends on the relative concentration of solutes on the two sides of the membrane. |
| When the concentration of the of the solute molecules outside the cell is LOWER than the concentration in the cytosol the solution outside is ________________________ to the cytosol. | hypotonic |
| When the concentration of solute molecules outside the cell is HIGHER than the concentration in the cytosol, the solution outside is ____________________ to the cytosol. | hypertonic |
| The situation in which water diffuses INTO the cell until equilibrium is established. | hypotonic |
| The situation in which water diffuses OUT OF the cell until equilibrium is established. | hypertonic |
| When the concentrations of solutes outside and inside the cell are equal, the outside solution is said to be _____________________ to the cytosol. | isotonic |
| Under the __________________ conditions, water diffuses into and out of the cell at equal rates so there is no net movement of water. | isotonic |
| If the solution outside the cell is ____________________ to the cytosol, then the cytosol must be _____________________ to the solution | hypertonic |
| If the solution outside is hypertonic to the cytosol, m then the cytosol must be _______________________ to the solution, | hypotonic |
| What are contractile vacuoles? | Organelles to remove water. |
| What is the purpose of contractile vacuoles? | To collect excess water and then contract, pumping water out of the cell. Requires energy. |
| Most of the time, plant cells live in a __________________environment. The cells that make up plant roots may be surrounded by water. | hypotonic |
| The pressure that water molecules exert against the cell wall is called __________ ____________. | turgor pressure |
| How does water leave cells in a hypertonic environment? | through osmosis |
| what is plasmolysis? | Turgor pressure is lost as a result of cells shrinking away from the cell walls. This is the reason plants wilt. (Plants wilt when they don't have enough water.) |
| What is facilitated diffusion? | A type of passive transport used if molecules cannot diffuse rapidly through cell membranes. Molecules may not be soluble in lipid or too large to pass through the pores in the membrane. Aided by carrier proteins. |
| What are carrier proteins? | Specific proteins in the membrane that help molecules across the cell membrane. |
| Give an example of facilitated diffusion | The transport of glucose. |
| what is an ion channel? | Membrane proteins involved in passive transport. |
| Name four ions that are not soluble in liquids but are necessary for cell functions? | sodium, potassium, calcium, and chloride |
| How does an ion channel work? | they provide small passageways across the cell membrane through which ions can diffuse |
| What is active transport? | Cells move materials up their concentration gradient from an area of lower concentration to an area of higher concentration . Such movement is active transport. Unlike passive transport, it requires a cell to expend energy. |
| what is the sodium-potassium pump? | a carrier protein used in the active transport in animal cells. This pump works to maintain the concentration differences between sodium and potassium. |
| The process by which cells ingest external fluid, macromolecules, and large particles, including other cells is known as ____________________ | endocytosis |
| The pouch that pinches off from the cell membrane and becomes a membrane-bound organelle during endocytosis is called a __________________. | vesicle |
| What are the two types of endocytosis? | pinocytosis and phagocytosis |
| The material involved in the transport of solutes or fluids | pinocytosis |
| the material involved in the movement of large particles or whole cells | phagocytosis |
| How do unicellular organisms feed? | phagocytosis |
| These cells allow lysosomes to fuse with the vesicles that contain ingested bacteria and viruses | phagocytes |
| What type of enzymes destroy bacteria and viruses before they can harm an animal? | lysosomal enzymes |
| the process that is the reverse of endocytosis | exocytosis |
| What happens during exocytosis? | Vesicles in the cytoplasm fuse with the cell membrane, releasing their contents into the cell's external environment. |
| What process might cells use to release large molecules such as proteins? | exocytosis |
Created by:
D. Waara