Osmosis Flashcards
What is osmosis?
Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration.
What is a partially permeable membrane?
A partially permeable membrane has very small holes in it, allowing small particles (e.g. water molecules) through it, but not larger particles (e.g. sucrose molecules).
During osmosis in what direction do the water molecules pass through the partially permeable membrane?
Both ways, because water molecules move about randomly all the time.
During osmosis what direction is the net flow of water molecules?
There is a steady net flow of water into the region with less water molecules (e.g.into the stronger sucrose solution), because there are more water molecules on one side than the other.
Where is tissue fluid located?
Tissue fluid surrounds the cells in the body.
What does tissue fluid usually consist of?
Water, oxygen, glucose and other things dissolved in it.
What happens when a cell is short of water?
The solution inside the cell will be quite concentrated. Also meaning the solution outside the cell is more dilute. Causing water to move into the cell by osmosis.
What happens when a cell has lots of water?
The solution inside the cell will be more dilute. Causing water to be drawn out of the cell and into the fluid outside by osmosis.
What is the method of the experiment to show osmosis at work?
-Cut up potato into identical cylinders.
-Fill a beaker with water, another with a very concentrated sugar solution, and a few others in between.
-You measure the length of the cylinders put them in beakers for 30 minutes and measure them again.
-Longer cylinders mean water has been drawn in by osmosis.
-Shrunken cylinders mean water has been drawn out by osmosis.
ID- concentration
DV- cylinder length
CV’s- solution volume, temperature, time, type of sugar used, must be kept the same for a fair test.
