SB1i: Transporting Substances Keywords Flashcards
Active transport
The movement of particles across a cell membrane from a region of lower concentration to a region of higher concentration (against the concentration gradient). The process requires energy.
Diffusion
When particles spread and mix with each other without anything moving them. Diffusion into and out of cells occurs for particles that are small enough to pass through the cell surface membrane.
Concentration
The amount of a solute dissolved in a certain volume of solvent. Measured in units such as g/cm3.
Concentration gradient
The difference between two concentrations. There will be an overall movement of particles down a concentration gradient, from higher concentration to lower concentration.
Osmosis
The overall movement of solvent molecules in a solution across a partially permeable membrane, from a dilute solution to a more concentrated one.
Passive
A process that does not require energy is passive. A passive process is the opposite of an active process (which requires energy).
Semi-permeable
Describes something that will allow certain particles to pass through it but not others. Another term for ‘partially permeable’.
Solute
The solid that has dissolved in a liquid to make a solution
Solvent
The liquid in which a substance dissolves to make a solution.