front 1 A cell must exchange its materials with its surroundings a process controlled by | back 1 The plasma membrane |
front 2 Plasma membranes are selectively permeable regulating what? | back 2 the cell's molecular traffic |
front 3 What can dissolve in the lipid bilayer and pass through the membrane rapidly | back 3 hydrophobic (non polar) molecules, such as hydro carbons |
front 4 What does not pass through the membrane easily? | back 4 Polar molecules such as sugars |
front 5 transport proteins allow passage of hydrophilic substances where? | back 5 Across the membrane |
front 6 What are aquaporins? | back 6 Channel proteins that facilitate the passage of water |
front 7 These transport proteins bind to molecules and change shape to shuttle them across the membrane | back 7 Carrier proteins |
front 8 a transport protein is specific for? | back 8 the substance it moves |
front 9 what is diffusion? | back 9 The tendency for molecules to spread out evenly in the available space. |
front 10 Transport proteins allow what? | back 10 passage of hydrophilic substances across the membrane |
front 11 Although each molecule moves randomly, diffusion of a population of molecules may be what? | back 11 directional |
front 12 as many molecules cross the membrane in one direction as in the other | back 12 dynamic equilibrium |
front 13 The region along which the density of a chemical substance increases or decreases? | back 13 concentration gradient, where substances diffuse |
front 14 How much work must be down to move substances down there concentration gradient? | back 14 none |