3. Movement in and out of cells Flashcards
Diffusion
Diffusion is the net movement of molecules from a region of its higher concentration to a region of its lower concentration, as a result of their random movement.
Where does the energy for movement in diffusion comes from?
Kinetic energy of the molecules
Why is diffusion of gases very important?
Helps in respiration
Diffusion of liquids important?
Helps plants in movement of nutrients
Factors affecting diffusion
CSTD
Concentration Gradient - Concentration increases, diffusion increases
Surface Area - Surface area increases, Diffusion increases.
Temperature - Temperature increases, Diffusion increases
Diffusion Distance - Greater Diffusion distance, diffusion slows down.
Osmosis
Osmosis is the diffusion of water molecules from a dilute solution (high concentration of water) to a more concentrated solution (low concentration of water) across a partially permeable membrane
Hypotonic Solution
Has a higher water potential than the water potential of the cell.
What happens when you place an animal cell in the hypotonic solution
There is a net movement of water into the cell which makes it burst (lysis)
Turgid
Cells are described as turgid when they are swollen due to high water content
Turgor Pressure
The pressure on the cell wall from the cell membrane pushing upon it. This is the result of cell becoming turgid as water moves into the cell due to osmosis
Flaccid
Occurs when water moves out of cell through osmosis. The cell shrinks but the cell membrane does not peel away from the cell wall
Plasmolysis
Occurs when there is too little water in the cell. In plant cells, the cell membrane peels away from the cell wall.
Hypertonic solution?
A solution that has lower water potential than the water potential of the cell
Animal cell in Hypertonic?
Net movement of water out of cell, which causes animal cell to shrink
Plant cell in hypertonic solution?
Net movement of water out of cell, which causes the cell to become plasmolysed
