movement of substances in and out of the cell Flashcards
What are cells surrounded by? What must cell let in?
Cell are surrounded by a cell membrane that separates the cell from the outside environment. The cell membrane is selectively permeable, which means that some substances can pass through the membrane while others cannot. Cell must let in needed materials, such as oxygen and food molecules, in contrast waste materials must move out of cells.
What is diffusion? What causes diffusion?
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. As the particles move, they bump into one another. The more molecules in an area, the more collisions. Collisions cause molecules to push away from one another and they will spread throughout the area.
What is osmosis?
Osmosis is the diffusion of water molecules through a selectively permeable membrane. The movement of water molecule from an area where they are highly concentrated through the cell membrane to an area where they are less concentrated.
What happen to cells when they are in a isotonic solution? What is an isotonic solution?
Isotonic solution means concentrations. Te concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell. Water molecules move into and out of the cell at the same rate, and cells retain their normal shape. A plant cell has its normal shape and pressure in an isotonic solution.
What happen to cells when they are in a hypotonic solution? What is an hypotonic solution?
Hypotonic solution has a dilute solution thus low solute concentration. In a hypotonic solution, water enters a cell by osmosis, causing the cell to swell.
Plant cells swell beyond their normal size as pressure increases. Plants like and prefer this because it makes their leaves firm.
What happen to cells when they are in a hypertonic solution? What is an hypertonic solution?
Hypertonic solution is a concentrated solution, thus a high solute concentration. In a hypertonic solution, water leaves a cell by osmosis, causing the cell to shrink. Plant cells lose pressure as the plasma membrane shrinks away from the cell wall.
