12). Define the following terms: semi-permeable membrane, solvent, solute, diffusion, osmosis, osmotically active substances, hypertonic, isotonic, hypotonic, Brownian movement, plasmolysis, turgor pressure, hypothesis, concentration gradient. I have a biology lab exam coming up this is one of the review topic questions. I would appreciate the help. Solution semi-permeable membrane:A semipermeable membrane is a barrier that allows only certain molecules or ions to pass through, while blocking others. Molecules pass through the membrane via osmosis, which is the passage of any substance through diffusion, or the tendency of molecules to move from an area where they exist in higher concentrations to an area of lower concentration .it is also called selective membrane. .eg:thin film membrane that lines the inside of an egg. solvent:A substance that can dissolve another substance, or in which another substance is dissolved, forming a solution. eg:water. solute: the minor component dissolved in a solution, the dissolved substance is called a solute .eg:sugar is the solute . diffusion:diffusion is a type of transport that moves molecules or compounds in or out of a cell. There are three main types of diffusion, which include simple diffusion, channel diffusion and facilitated diffusion. eg:A teabag placed in a cup of hot water will diffuse into the water. osmosis:.Osmosis is a special example of diffusion. It is the diffusion of a substance through a semipermeable membrane from a more dilute solution to a more concentrated solution. This process is also passive since no external energy is needed. eg:Absorption of water by plant roots. osmotically active substances:In order to have osmosis first of all you need to have a semi- permeable membrane separating two solutions. In order to have net water movement from one solution to the other you need to have different concentrations of solutes that cannot pass through the membrane. These solutes are osmotically active: since they cannot pass through the membrane water has to move in order to equilibrate the osmotic pressures. If they could pass through the membrane then they would just diffuse from one solution to the other until their concentration equilibrates and thus they would not contribute to the generation of osmotic pressure.(or) osmotic active substances are substances that do not pass through cell membrane. e.g: proteins are large they dont pass through membranes directly so they suck water from interstitial fluid to the vessels. hypertonic:Ahypertonic solution is a particular type of solution that has a greater concentration of solutes on the outside of a cell when compared with the inside of a cell. eg: glucose dissolved into it is any plain glucose solution with a concentration higher than 5%. isotonic:An isotonic solution refers to two solutions having the same osmotic pressure across a semipermeable membrane. This state allows for the free movement of water across the membrane without cha.

1. 12). Define the following terms: semi-permeable membrane, solvent, solute, diffusion, osmosis,
osmotically active substances, hypertonic, isotonic, hypotonic, Brownian movement,
plasmolysis, turgor pressure, hypothesis, concentration gradient.
I have a biology lab exam coming up this is one of the review topic questions. I would appreciate
the help.
Solution
semi-permeable membrane:A semipermeable membrane is a barrier that allows only certain
molecules or ions to pass through, while blocking others. Molecules pass through the membrane
via osmosis, which is the passage of any substance through diffusion, or the tendency of
molecules to move from an area where they exist in higher concentrations to an area of lower
concentration .it is also called selective membrane.
.eg:thin film membrane that lines the inside of an egg.
solvent:A substance that can dissolve another substance, or in which another substance is
dissolved, forming a solution.
eg:water.
solute: the minor component dissolved in a solution, the dissolved substance is called a solute
.eg:sugar is the solute .
diffusion:diffusion is a type of transport that moves molecules or compounds in or out of a cell.
There are three main types of diffusion, which include simple diffusion, channel diffusion and
facilitated diffusion.
eg:A teabag placed in a cup of hot water will diffuse into the water.
osmosis:.Osmosis is a special example of diffusion. It is the diffusion of a substance through a
semipermeable membrane from a more dilute solution to a more concentrated solution. This
process is also passive since no external energy is needed.
eg:Absorption of water by plant roots.
osmotically active substances:In order to have osmosis first of all you need to have a semi-
permeable membrane separating two solutions. In order to have net water movement from one
solution to the other you need to have different concentrations of solutes that cannot pass through
the membrane. These solutes are osmotically active: since they cannot pass through the
membrane water has to move in order to equilibrate the osmotic pressures. If they could pass
through the membrane then they would just diffuse from one solution to the other until their
concentration equilibrates and thus they would not contribute to the generation of osmotic
pressure.(or)

2. osmotic active substances are substances that do not pass through cell membrane.
e.g: proteins are large they dont pass through membranes directly so they suck water from
interstitial fluid to the vessels.
hypertonic:Ahypertonic solution is a particular type of solution that has a greater concentration
of solutes on the outside of a cell when compared with the inside of a cell.
eg: glucose dissolved into it is any plain glucose solution with a concentration higher than 5%.
isotonic:An isotonic solution refers to two solutions having the same osmotic pressure across a
semipermeable membrane. This state allows for the free movement of water across the
membrane without changing the concentration of solutes on either side.
eg:saline solution.
hypotonic: Ahypotonic solution is any solution that has a lower osmotic pressure than another
solution. this generally refers to a solution that has less solute and more water than another
solution.
eg:0.45% sodium chloride , commonly called half normal saline.
Brownian movement:The random movement of microscopic particles suspended in a liquid or
gas, caused by collisions with molecules of the surrounding medium. Also calledBrownian
motion, molecular movement, pedesis(or)Brownian movement.
eg:
The movement of the charcoal in this example is Brownian movement .
plasmolysis,:plasmolysis is stated as the contraction of the protoplasm of cells within plants due
to the loss of water through osmosis. It is when the cell membrane peels off of the cell wall and
the vacuole collapses when placed in a hypertonic environment The process of plasmolysis
occurs when water is drawn out of the cell into fluids outside of the cell through the process of
osmosis.
(or)
plasmolysis is a process where a cell contents shrink away from the cellwall when placed in
hypertonic solution.
.eg:if red blood cells are placed in a strong salt solution plasmolysis occur.
turgor pressure:it is the pressure that pushes the plasma membrane against the cell wall of plant,
bacterial, and fungal cells as well as those protist cells which have cell walls.
eg: An example of turgor pressure is osmosis which causes water to flow from an area of low
solute concentration to an area of high solute concentration until the two areas are equal.
hypothesis:A supposition or tentative explanation for phenomena, a set of facts, or a scientific
inquiry that may be tested, verified or answered by further investigation or methodological
experiment.
eg:someone performing experiments on plant growth might report this hypothesis:

3. concentration gradient:. A concentration gradient is the change in concentration in a solution
measured over the distance.
An example of concentration gradient is food dye diffusing in a glass of water.