movement ˚ ༘ ⋆

• concentration gradient: is the difference in concentration between 2 regions
• diffusion: is the net movement of particles from a region of high concentration to low concentration down a concentration gradient
• factors that affect rate of diffusion

  1. concentration gradient
  2. diffusion distance
  3. surface area-to-volume ratio
• osmosis: is the net movement of water molecules from a region of higher water potential to a region o lower water potential through a partially permeable membrane
• water potential: is a measure of the tendency of water molecules to move from one place to another
• active transport: is the process in which energy is used to move the particles of a substance across a membrane against its concentration gradient that is from a region where the particles are of lower concentration to a region of high concentration
• active transport occurs when living things respire & uses energy from respiration
• energy is needed for active transport to take place
• animal cell when placed in a solution of higher water potential will swell and eventually burst due to absence of cell wall
• animal cell when placed in a solution of lower water potential will shrink in size and shrivel ( crenation ) eventually becomes dehydrated and dies
• plant cell when placed in a solution of higher water potential will become turgid and is prevented from bursting by rigid and inelastic cell wall
• plasmolysis: plant cell when placed in a solution of lower water potential will become flaccid
• importance of turgor pressure is to maintain the shape of soft tissues in plants and causes the opening and closing of stomata