| Term | Definition |
|---|
| Active transport does not require energy (ATP) to function. | False. |
| Osmosis is the diffusion of water across a semi-permeable membrane. | True. |
| Temperature can influence diffusion. | True. |
| Exocytosis is the process of moving material from the outside of the cell to the inside of the cell. | False. |
| Diffusion requires a transport protein. | False. |
| If two solutions separated by a semi-permeable membrane have the same solute concentration they are isotonic. | True. |
| Simple nonpolar molecules pass through membranes by diffusion. | True. |
| Polar molecules and ions pass through membranes by diffusion. | False. |
| Active transport can move molecules from an area of low concentration to an area of high concentration. | True. |
| Active transport requires energy in the form of ATP. | True. |
| Size of a molecule can influence diffusion. | True. |
| In diffusio, substances move up a concentration gradient. | False. |
| How many layers of lipids are their in a cell membrane? | Two, a bilayer. |
| What kind of lipid if found in a cell membrane? | Phospholipids. |
| Are proteins found in cell membranes? | Yes, diverse proteins. |
| Where are the hydrophobic parts of the lipids located? | They are sandwiched between hydrophilic parts, which are dissolved in cytoplasmic fluid or in ECF. |
| What do all cell membranes have? | Protein receptors, transporters, and enzymes. |
| What kind of proteins to plasma membranes incorporate? | Adhesion, communication, and recognition proteins. |
| What do all proteins have that passively and actively assist waste-soluable substances across the lipid bilayer? | Transporters. |
| What kind of proteins are there in the cell membrane? | Adhesion, Communication, Receptor, and recogition proteins. |
| What kind of transporters are there in the cell membrane? | Passive and active. |
| What are Adhesion proteins? | Help cell of the same type locate each other and remain in the proper tissue. |
| What are Communication proteins? | Form channels that match up across the plasma membranes of two sells. They let signals and substances rapidly flow from the cytoplasm of one into the other. |
| What are Recognition proteins? | Bind extracellular substances, such as hormones, that can trigger change in cell activities. |
| What are transport proteins? | Either passively let specific solutions diffuse through a membrane spanning channel in their interior, or actively pump them through. In all cell membranes. |
| What is diffusion? | The net movement of molecules or ions of a substance into an adjoining region where they are not as concentrated. |
| What can affect the diffusion rate? | The steepness of a concentration gradient as well as temperature, molecular size, and electric and pressure gradients. |
| What can decrease or increase the concentration gradient across cell membranes? | Cellular mechanisms. |
| What is a concentration gradient? | A difference in the number per unit volume of molecules or ions of a substance between two adjoining regions. |
| What is an electric gradient? | Direction of diffusion. |
| What is a pressure gradient? | Difference in pressure exerted per unit volume or area between two adjoining regions. |
| What is selective permeability? | They allow some substances but not others to enter and leave a cell. Also control when each substance can cross and how much crosses at a given time. |
| What is passive transport? | Facilitated diffusion. Transporter allows a solute to cross a cell membrane by diffusing through its interior. |
| What is active transport? | Net diffusion of a specific solute is against its gradient. The transporter must be activated, usually by an energy input from ATp, which counters the force inherent in the gradient. |
| What is endocytosis? | A vesicle forms around particles when a patch of plasma membrane sinks inward and seals back on itself. |
| What is exocytosis? | A vesicle that formed in the cytoplasm fuses with the plasma membrane, so that its contents are releasd to the outside. |
| What continually helps lower or raise gradients across a membrane, that helps the cell respond to signals and to chemical changes? | Passive and active transport. |
| What is a calcium pump? | Active transporter that helps keep the concentration of calcium in a cell at least a thousand times lower than outside. |
| What is the sodium-potassium pump? | Cotransporter that move two kinds of ions in opposite directions. |
| What is Bulk flow? | The mass movement of one or more substances in response to pressure, gravity, or another external force. |
| What is a hypotonic solution? | Fewer solutes. |
| What is a hypertonic solution? | More solutes. |
| What is a Isotonic solution? | No net osmotic movement, equal. |
| Where does water tend to move osmotically? | Regions of greater solute concentration, hypotonic to hypertonic solutions. |
| What is hydrostatic pressure? | Turgor pressure, against the wall or membrane that contains it. |
| What is osmotic pressure? | One measure of the tendency of water to follow its concentration gradient and move into that fluid. |
| When hydrostatic pressure and osmotic pressure are equal what happens? | Osmosis stops. |
| What do exocytosis and endocytosis move? | Large packets of materials in bulk across a plasma membrane. |
| What is Phagocytosis? | Form of endocytosis by which predatory amoebas engluf prey and certain white blood cells actively engulf tissue invaders, tissue debris, and cancer cells. |
| What is bulk phase? | Type of endocytosis. A vesicle forms around a small volume of the ECF reardless of the kinds of substances dissolved in it. |
| What is receptor mediated? | Endocytosis. A hormone, vitamin, or mineral or another substance binds with a receptor at the plasma membrane. A slight depression, or pit, forms in the plasma membrane beneth the receptor. The pit sinks into the cytoplasm and hydrophobic interactions cause a vesicle to form. |
| In the lipid bilayer, what are the heads? | Hydrophilic. |
| In the lipid bilayer, what are the tails? | Hydrophobic. |
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