Osmosis Flashcards
Define
The net passive movement of water from an area of high water concentration to an area of low water concentration
How can water move through a semi-permeable membrane, although it is hydrophilic (polar)
Due to water’s extremely small size
Why is osmosis an important part of biology in relation to sugar molecules an example of a solute
Due to the semipermeable nature of the plasma membrane it makes it difficult for molecules to simply diffuse across it
Water molecules can though due to their small size
Sugar molecules (an ex. of a solute) struggles to simply diffuse across the plasma membrane
However, it can use facilitated diffusion but water travelling across the membrane is a more efficient way to dilute the sugar molecules and therefore equalise the amount of solute on either side of the plasma membrane
How can we increase the amount of water movement through osmosis
An increase in protein channels known as aquaporins
Tonicity
A way of measuring the solute concentrations on either side of the plasma membrane by using the terms hypotonic, hypertonic, and isotonic
Hypotonic
A solution in which there is a lower amount of solute compared to the extracellular environment
Hypertonic
A solution in which there is a higher concentration of solute compared to the extracellular environment
Isotonic
The net movement of water is zero due to an equal amount of water moving inside and outside the cell due to the equal concentrations of solute on either side of the plasma membrane
Even though a solution is isotonic and there is no net movement of water - is there still movement of water
Yes because water is still moving inside and outside but it is to an equal amount and therefore, no net movement due to the equal amount of solute concentrations on either side of the plasma membrane
Effects of tonicity on cells
Impacts the size of a cell
Hypertonic solution explain how this affects the net passive movement of water
Water moves into the cell because the cell is in a hypertonic solution (in which there is a high solute concentration and a low solvent)
Net passive movement of water from an area of high water concentration to an area of low water concentration
Effect of the net passive movement of water into the plant and animal cell resulting from the hypertonic solution in which it was placed
Animal cell:
Lysed (plasma membrane bursts due to the lack of a cell wall)
Plant cell:
Turgid (swollen and firm from water uptake but does not burst like an animal cell does because of the cell wall)
Hypotonic solution explain how this affects the net passive movement of water
Because the net passive movement of water is directed outside of the cell due to the hypotonic solution in which the cell was placed (a low solute concentration compared to a high solvent concentration outside the cell)
Therefore, water moves into the cell in order to fulfill its requirement as part of the process of osmosis
Effect of net passive movement of water into the plant and animal cells and explain this in relation to specific terms
Animal cell:
Shrivelled (shrinks due to loss of water)
Plasmolysed (weak and sagging plasma membrane due to the loss of water)
