movement in and out of cells Flashcards
what is diffusion
This is the movement of molecules from a region of high concentration to a region of low concentration down the concentration gradient.
the energy for diffusion comes from
the kinetic energy of random movement of
molecules and ions
This results in random movement of molecules until equilibrium is reached
Describe the importance of diffusion of gases and
solutes
The diffusion of gases and solutes is important as without it, molecules which are needed for life, for example glucose and oxygen for respiration, would not be able to get to the places they are needed. Water is needed as a solvent
Factors influencing faster diffusion:
Larger concentration gradient
Higher temperature
Smaller surface area
what is osmosis
Movement of water molecules from a region of high-water potential to a region of low water potential, through a partially permeable membrane
what is plasmolysis
Conc. of solute outside cell > conc. inside cell → cell shrinks (Plasmolysis)
what is turgidity
Conc. of solute outside cell < conc. inside cell → cell swells (Turgid)
osmosis in plants
Increasing solute concentration inside of cell causes cell to become turgid, vacuole fills up.
Decreasing solute concentration inside of cell causes cell to become flaccid, losing water and vacuole gets smaller. Cell body shrinks, pulling away from cell wall
osmosis in animals
Increasing solute concentration inside of cell can cause cell to explode as a result of it having too much water, crenation.
what is active transport
Movement of particles through a cell membrane, from a region of lower concentration to a region of higher concentration against a concentration gradient, using energy released during respiration
why is active transport needed
Active transport is needed when an organism wants to optimize the amount of nutrients it can take up - ion uptake by root hairs and uptake of glucose by epithelial cells of villi.
