Diffusion and Osmosis Flashcards
What occupies the empty area of a plasmolysed cell?
Sugar Solution
What is observed when water is placed above a liquid of lower water potential?
After 1 hour, the liquid with lower water potential would have moved slightly up the gas jar.
Define osmosis.
Osmosis is the movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.
Why does something increase in size when placed in water?
The object becomes more turgid as water molecules move from the distilled water into the object via osmosis.
Why does something decrease in size when placed in liquid x?
The object becomes flaccid as water molecules move from the the object into liquid x via osmosis.
Why does a strip bend outwards when placed in a solution with lower water potential (liquid x)?
The cells along the cut surface swell and become turgid as water enters the cell from the liquid x via osmosis. However water does not enter due to the presence of waterproof waxy cuticle. Hence the unequal expansion causes the strip to bend outwards.
Define diffusion
Diffusion is the net movement of particles from a region of higher water potential of that molecule to a region of lower water potential of that molecule down a concentration gradient until the mixture is homogenous.
What happens when a thistle funnel containing Liquid X is placed in a beaker of water?
There are more water molecules in the beaker as compared to the thistle funnel. Therefore the water concentration in the beaker is higher than that of the thistle funnel. Water molecules thus move via the process of osmosis from a region of higher water potential (the beaker) to a region of lower water potential (the thistle funnel).
What happens during turgid cell?
Water moves from the solution into the cell. Vacuole increases in size, pushes cell against the cellulose cell wall. Plant cell does not burst due to the presence of the cellulose cell wall which is relatively strong and elastic. Plant cell become turgid.
What happens during cell lysis?
Water moves from the solution into the cell. Animal cell swells and may burst as it does not have a cell wall.
What happens during plasmolysis?
When a plant cell is placed in a solution of lower water potential, water moves out from the cell into the solution. As water leaves the cell, the vacuole decreases in size and shrinks away from the cellulose cell wall. The cell is plasmolysed.
What happens during crenation?
When an animal cell is placed in a solution of lower water potential, water moves out from the cell into the solution. The cell membrane forms little spikes as water moves out of the cell. The cell shrinks.
