Lesson 3 - Osmosis Flashcards
(29 cards)
meaning osmotic concentration
a measure of the concentration of the solutes in a solution that have an osmotic effect
meaning isotonic solution
a solution in which the osmotic concentration of the solutes is the same as that in the cells
meaning hypertonic solution
a solution in which the osmotic concentration of solutes is higher than that in the cell contents
meaning hypotonic solution
a solution in which the osmotic concentration of solutes is lower than the cell contents
meaning pressure potential
a measure of inward pressure exerted by the plant cell wall on the protoplasm of the cell, opposing the entry of water by osmosis. It usually has a positive value
meaning turgor
the state of a plant cell when the solute potential causing water to be moved into the cell by osmosis is balanced by the force of the cell wall pressing on the protoplasm
meaning incipient plasmolysis
the point at which so much water has moved out of the cell by osmosis that turgor is lost and the cell membrane begins to pull away from the cell wall as the protoplasm shrinks
meaning plasmolysis
the situation when a plant cell is placed in hypertonic solution when so much water leaves the cell by osmosis that the vacuole is reduced and the protoplasm is concentrated and shrinks away from the cell walls
meaning water potential
a measure of the potential for water to move out of a solution by osmosis
meaning turgor pressure
a measure of the inward pressure exerted by the plant cell wall on the protoplasm of the cell as the cell contents expand and press outwards, a force which opposes the entry of water by osmosis
meaning osmotic potential
a measure of the potential of a solution to cause water to move into the cell across a partially permeable membrane as a result of dissolved solutes
meaning free water molecules
water molecules that are not involved in hydrogen bonding/ any type of bonding, that move easily through partially permeable membranes
give 2 examples of particles that are considered when talking about osmotic concentration
big plasma proteins e.g. albumin & fibrinogen
how to model osmosis in cells
use an artificial membrane. The presence/ absence of sucrose in different regions can be shown by carrying out the benedict’s test for non-reducing sugars
how is osmosis controlled in animals and plants
the net movement of water in and out needs to be kept to a minimum
what happens when too much water moves out of an animal cell
the cell shrivels as the concentrated cytoplasm loses its internal structure and the chemical reactions that normally take place in the cell stops working
what happens when too much water moves in an animal cell
the cell bursts
what is a plant cell wall made out of
cellulose
state the definition of osmosis, by water potential
the net movement of water molecules from an area of high water potential to an area of low water potential through a partially permeable membrane
state the definition of osmosis, by osmotic potential
the net movement of water molecules from an area of higher osmotic potential to an area of lower osmotic potential through a partially permeable membrane
how to calculate water potential of a cell (usually negative)
turgor pressure (+) + osmotic potential (-)
what happens when a plant cell is placed in pure water
the pure water will act as a hypotonic solution, so the water will move into the plant cell by osmosis, down the concentration gradient. The plant cell will become turgid
what happens when a plant cell is placed in a concentrated solution
the concentrated solution will act as a hypertonic solution, so the water from the plant cell will move out of the cell by osmosis, down the concentration gradient. The pant cell will become flaccid, and plasmolysis may occur
in the potato chip experiment:
Why were the pieces of potato all taken from the same potato
different potatoes have different water solute concentrations
