Question | Answer |
What is the function of the plasma membrane? | Isolates the cells contents from environment |
What are membranes? | Membranes are dynamic, ever-changing structures |
What are phospholipids? | Phospholipids are the basis of membrane structure |
What is a phospholipid head? | 1 Polar, hydrophillic head |
What is a phospholipid tail? | 2 Non-polar, hydrophobic heads |
Why is the phospholipid bilayer flexible and fluid? | Allows for cellular shape changes |
What makes the phospholipid membrane fluid? | Unsaturated fatty acids |
Where are proteins embedded? | Phospholipid bilayer |
What is the main role of a transport protein? | Transport substances |
What is a fluid? | Substance that can move or change shape in response to external forces |
What is a solute? | Substance that can be dissolved in a solvent |
What is a solvent? | Fluid capable of dissolving a solute |
What is concentration? | Concentration is the number of molecules in any given volume unit |
What is a gradient? | Physical difference in concentration of two adjacent regions |
What is diffusion? | Molecules move from areas of high concentration to low concentration until a dynamic equilibrium is reached |
Does diffusion ever stop moving? | No! |
What are the two types of movements across the plasma membrane? | Passive transport and energy requiring transport |
What is a selectively permeable membrane? | Membrane that chooses which molecules may pass through and which may not |
What is passive transport? | Substances move down their concentration gradient across a membrane. |
What is allowed through the cell membrane? | Small, non-polar molecules (no charge) |
What is not allowed through the cell membrane? | Charged, polar, and large molecules |
Is energy required in diffusion? | No! |
How do molecules distribute themselves? | Equally |
What is osmosis? | Water diffuses from high concentration to low concentration across a membrane (Water only!) |
What is a hypotonic solution? | High water concentration, lower dissolved solutes |
What is a hypertonic solution? | Low water concentration, high dissolved solutes |
What is an isotonic solution? | Equal concentrations of solutes in water and in cell |
What is water attracted to? | Things with a charge; solutes |
What is facilitated diffusion? | Water soluble molecules (like ions, amino acids, and sugars) diffuse with the aid of carrier transport proteins |
What aids facilitated diffusion? | Carrier transport proteins |
What is active transport? | Energy pumps solutes from areas of low concentration to high concentration (opposite of diffusion) |
What concentrations does active transport go from? | Low to high |
What concentration does diffusion go through? | High to low |
What is the main role of membrane proteins? | Transport important substanecs |
What is bulk transport known as? | Endocyotsis |
What is pinocytosis? | Cell drinking |
What is phagocytosis? | Cell eating |
What is exocytosis? | Vesicles join membrane, dumping out contents |
Does exo/endocytosis require energy? | Yes, lots of it! |