cell division + osmosis Flashcards
define diffusion
the movement of molecules from an area of high concentration to low concentration e.g absorption through the villi in the small intestine
is energy needed for diffusion
no, diffusion is a passive process
define active transport
the movement of molecules from an area of low concentration to a high concentration e.g reabsorption of nephron in the kidney
is energy needed for active transport
yes, it require ATP as the movement is against the concentration gradient
define osmosis
the movement of water molecules from an area of high concentration to low concentration across a semi-permeable membrane.
does osmosis require energy
no, it is a passive process
define solvent
a liquid that dissolves other substances, water is the universal solvent
define solute
a substance that has been dissolved in a solvent e.g salt
define solution
a mixture of solvent and solute e.g salty water
give an example of osmosis
water moving from cell to cell in transpiration
give an issue that can arise from osmosis
an animal cell may burst if placed in a concentrated solution
how can osmosis be used in real life
salting food- water is drwn from bacteria cells and denatures bacterial enzymes which kills all bacteria
define turgor pressure
the pressure of the cytoplasm and vacuole against the cell wall of a plant. allows the plant to be stiff and stand upright
define plasmolysis
the shrinking of the cytoplasm + cell membrane away from the cell wall of a plant/bacteria cell due to water loss from osmosis
explain the steps you took to investigate osmosis
soften 2 strips of visking tubing by soaking them in water. tie a knot on one end of both the tubes. dissolve sucrose in water. half fill one tube with the sucrose solution, and the other one with water. tie the ends of the tubes. record the mass of each bag. leave both bags in a beaker of water for 20 mins. record mass again
