Movement In And Out Of Cells Flashcards
What is diffusion?
The net movement of particles from an area of high concentration, to an area of low concentration, down the concentration gradient, as a result of their random movement
What is diffusion used for in living organisms?
Obtain many of their requirements, get rid of many of their waste products, carry out gas exchange for respiration
What is a partially permeable membrane?
A membrane that only allows certain molecules to pass through it
What is the Brownian motion?
All particles move randomly at all times
From where does the energy for diffusion come from?
The energy for diffusion comes from the kinetic energy of this random movement of molecules and ions
How does the surface area to volume ratio affect the rate of diffusion?
The bigger a cell or structure is, the smaller its surface area to volume ratio is, slowing down the rate at which substances can move across its surface
What is osmosis?
Osmosis is the diffusion of water molecules from a dilute solution (high concentration of water) to a more concentrated solution (low concentration of water) across a partially permeable membrane.
What is dialysis tubing?
A non-living partially permeable membrane made from cellulose
What is a turgid plant cell?
Water molecules push the cell membrane against the cell wall, increasing the turgor pressure in the cells which makes them turgid
What is a plasmolysed plant cell?
The cell membrane has pulled away from the cell wall
What is a flaccid plant cell
Flaccid refers to a situation in which plant cells are suspended in an isotonic solution, the cell may collapse.
What is a hypertonic solution?
Higher concentration in the cell than outside the cell, therefore the solution has a lower water potential and the cells become crenated (shrivelled up).
What is an isotonic solution?
Equal water potential, there is movement but NO net movement, normal cell environment.
What is a hypotonic solution?
Lower water potential inside the cell so the cells swell and may lyse (burst), (cells in distilled water have the same reaction)
What is active transport?
Active transport is the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
