Water In Cells Flashcards
What is osmosis?
Osmosis is the movement of water through a membrane.
How does osmosis relate to the movement of water molecules?
Osmosis is the movement of water molecules from a region with a high concentration of water molecules to a region with a lower concentration of water molecules through a cell’s partially permeable membrane in order to make the concentrations more equal.
What is the purpose of osmosis?
The purpose of osmosis is to stabilize the internal environment of a cell by balancing the levels of water and intracellular fluids to achieve a balanced amount of water inside and outside the cell (equalibirum of water concentration)
What is a hypotonic solution?
The concentration of solute in an external solution is lower than the concentration of solute in a cell.
If a cell is in a hypotonic solution it will become bigger and swell because water enters and is being gained from osmosis. The mass of the cell will increase and the cell will gain volume.
Net inflow of water molecules
What is a hypertonic solution?
The concentration of solute in an external solution is higher than the concentration of solute in a cell.
When a cell is in a hypertonic solution water will move out of the cell to the region of higher solute concentration which causes the cell to shrink. The mass of the cell will decrease.
Net outflow of water molecules
What is an isotonic solution?
An isotonic solution is when the concentration of solute is the same in the external solution and the internal cell.
Water that is separated by a semipermeable membrane moves freely in and out of a cell.
The mass of a cell doesn’t change.
No net flow of water molecules.
What is osmotic pressure?
Osmotic pressure is the pressure required to stop water from diffusing through a membrane by osmosis. It is determined by the concentration of the solute.
What is diffusion?
Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with lower concentration down the concentration gradient.
What is concentration gradient?
Concentration gradient is the difference in concentration of a substance from one point to another. Concentration gradients support processes like diffusion, osmosis, and cell signalling.
What is concentration?
Concentration is the amount of substance, such as salt, that is an a certain amount of tissue or lipid.
What is turgor pressure?
Turgor pressure is the force within the cell that pushes the cell membrane against the cell wall.
An increase of turgor pressure is caused by inward diffusion of water into a cell.
A loss of turgor pressure is caused by the loss of water.
What is cytolysis?
Cytolysis is when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell.
What do the prefixes hyper, hypo, and iso mean?
Hyper= more
Hypo=less
Iso=equal
How is diffusion related to hypertonic solutions?
If a cell is surrounded by a hypertonic solution, the water molecules will diffuse out of the cell because it has a lower concentration of water molecules and the cell has a higher concentration of water molecules (lower concentration of solute-bond molecules)
How is diffusion related to hypotonic solutions?
If a cell is surrounded by a hypotonic solution, water diffuses into the cell because the solution has a higher concentration of water molecules and the cell has a lower concentration of water molecules (a high concentration of solute-bond molecules)
