Passive transport: energy not needed. Spreading out of particles of any gas/ solution resulting in the next movement of particles from area of high to low concentration
Use of diffusion in cells
Cells take in substances (glucose/ oxygen) for respiration
Get rid of waste/ chemicals (co2)
Urea (waste) released into blood plasma for excretion in kidney
Dissolved substances + gases move in/ out of cells through diffusion (cell membrane)
Factors affecting diffusion
Osmosis
Passive transport: energy not needed. Diffusion of water molecules from a dilute to concentrated solution through a partially permeable membrane
Concentration of solutions
Hypotonic: higher in solution
Hypertonic: lower in solution
Isotonic: same concentration in cell + solution
Reactions when cell placed into different solution concentrations
Hypotonic: water moves into cell -> turgor pressure
Hypertonic: water moves out of cell -> plasmolysis
Isotonic: water enters/ leaves cell at same rate= flaccid cell (same size/ mass)
Active transport
Substances moved against their concentration gradient (lower -> higher). Requires energy from respiration
Active transport in plants
Root hair cells have lots of mitochondria for energy
Energy + carrier proteins: bring mineral ions (nitrates/ phosphates) into cell
Water enters by osmosis
Active transport in humans
Gut/ kidney tubules= active absorption of glucose into blood
Glucose need for respiration: important to get a lot from gut
