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| Question | Answer |
| what is homeostasis | process by which an organism maintains a stable internal environment |
| What is thermoregulation | maintaining a body temperature |
| what is water regulation | maintaining enough water in the body |
| What are 2 functions of a plasma membrane | 1. encloses and protects the cell 2. allows certain particles in and out of it |
| what is selective permiability | the plasma membrane can pick and choose what particles can pass through it |
| 3 parts of a plasma membrane | phospholipids, proteins, and sometimes cholesterol |
| what is a phospholipid made from | a glycerol attached to 2 fatty acids and a phosphate group |
| the fatty acids in a phospholipid are _____________ meaning they hate water | hydrophobic |
| the phosphate group in phospholipids are ____________ (like water) | hydrophilic |
| draw or be able to picture the structure of a single phospholipid | |
| what does the bilayer structure look like in a plasma membrane | |
| what plasma membranes have cholesterol in between phospholipids and why? | Animal plasma membranes, and to make plasma membrane more firm, and less permeable for some molecules |
| Where can proteins be in membranes | they can be on the inner or outer surfaces, and some go through the bilayer |
| 3 jobs of the proteins in membranes | 1. regulate which particles can pass through membrane (transport) 2. act as ENZYMES in chemical reactions 3. act as MARKERS on outside of cell to identify itself |
| Study this (what a plasma membrane may look like) | |
| what is active transport | a way that requires energy to move molecules through the plasma membrane |
| what is passive transport | a way that does not require energy to move molecules through plasma membrane, occurs spontaneously |
| Define diffusion | the principle means of passive transport. Movement of molecules from a high concentration to a low concentration |
| study this (process of diffusion) | |
| What is equilibrium | When two opposing actions occur at the same rate |
| Finish the sentence: diffusion occurs when system is not at _________ | equilibrium |
| What 2 factors affect diffusion | TEMPERATURE (higher temperature means molecules will diffuse faster), and SIZE (smaller molecules will move more rapidly than larger ones) |
| steps of diffusion in the human body: (idk I feel like this could be an open ended question) | CO2 and O2 diffuse across plasma membranes O2 moves from high concentration to low from lungs to blood to cells as chemical reactions in cell use up O2 they produce CO2 concentration of Co2 increases, so more CO2 in side of the cell therefore CO2 diffuses into blood and then into lungs where it is exhaled |
| What is Osmosis | movement of water from high concentration to low. "DIFFUSION OF WATER" that can cause cells to burst or shrink |
| what is osmoregulation (remember homeostasis) | Saltwater fish get rid of salt and conserve water (scanty urine) Freshwater get salt and get rid of excess water (large amounts of dilute urine) |
| What determines the tonicity of cells | If the concentration of solution is not equal on both sides, there will be movement of water molecules in or out of cell. What direction water molecules are going determines where it is isotonic, hypotonic, or hypertonic |
| when does isotonic occur | movement of water out of the cell is balanced with movement of water into the cell. Example: saline solution is isotonic to human cells. |
| isotonic solution looks like: | |
| Hypotonic solution occurs when | dissolved solutions are less outside of the cell than inside the cell. (A LOT OF WATER GOING IN, NOT A LOT COMIN OUT) cells w/o walls can swell or burst! |
| hypotonic looks like: | |
| hypertonic occurs when: | concentrations of dissolved are GREATER outside the cell, so concentration of water inside the cell is LOWER. Cells get rid of water more than they take in water, start to shrink |
| a hypertonic solution looks like | |
| Tonicity in plant cells look like: | |
| In plant cells, plasmolyzed cells are _________, flaccid cells are ____________, and turgid cells are _____________. | Hypertonic, isotonic, hypotonic |
| what is facilitated diffusion? when does it occur? | When proteins help certain chemicals pass through a membrane. Requires NO ENERGY (passive transport) and it usually occurs for larger molecules like glucose |
| facilitated diffusion looks like: | |
| Active transport is when a cell _____________ energy to move from low to high concentration. Proteins pump _____________ through membranes. Molecules move _________ diffusion (from a low to high concentration) | NEEDS, MOLECULES, AGAINST |
| 3 OTHER WAYS CELLS GET MATERIALS | 1. vesicles 2. endocytosis 3. exocytosis |
| what is endocytosis | when the plasma membrane engulfs and takes in materials and puts them into a vesicle |
| what are the two types of endocytosis | Phagocytosis and Pinocytosis |
| Phagocytosis is when... | When living cells phagocytes engulf other cells or particles (remember this type of cell gets "PHAt" when it engulfs another cell) |
| Pinocytosis is when... | liquid droplets are ingested by living cells |
| exocytosis is when | a vacuole fuses to the cell membrane and releases its contents to the exterior |
| ways to remember difference between endocytosis and exocytosis | Endocytosis- cell is bringing food "en" (in) Exocytosis- contents are "EXiting" the cell |
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