Transport in Cells Flashcards
(15 cards)
what are the 3 types of transport in cells?
diffusion, osmosis and active transport
what is the definition of diffusion?
spreading out of particles in a net movement from an area of high concentration to low concentration
how does oxygen use diffusion?
-cells need oxygen for respiration
-cells are surrounded by high concentrations of oxygen
-transported in blood from lungs
-oxygen is used to generate energy in respiration, producing waste gas (CO2)
how does carbon dioxide use diffusion?
higher concentration of CO2 inside the cell
how does urea use diffusion?
waste product that diffuses out of the cells into the blood plasma and is excreted by the kidneys
what factors affect diffusion?
concentration gradient, temperature and surface area
what happens if all the factors are greater within diffusion?
CG - take place faster
T - more kinetic energy, particles move faster
SA - greater diffusion rate
what is the definition of osmosis?
diffusion of water from a dilute solution (high concentration of water) to a concentrated solution (low concentration of water) through a partially permeable membrane
what does the partially permeable membrane allow?
only some molecules to pass through
what effect does osmosis have on animal cells?
-water moving in will expand the cell or even burst it
-in a concentrated solution, water will move out causing it to shrink
what effect does osmosis have on plant cells?
-water moving in causes it to expand but cell wall prevents it from bursting
-becomes swollen (turgid)
-in a concentrated solution water will move out causing it to shrink (flaccid)
what is the definition of active transport?
moves substances from a low concentration to high concentration (against the concentration gradient) that requires energy
what are 2 key differences of active transport compared to diffusion?
in active transport particles move again the concentration gradient and it does require energy, where as in diffusion particles move down the concentration gradient and do not require energy
how does active transport occur in the lumen of the small intestines?
-concentration of sugars in the lumen is lower than in the cells
-sugars cannot diffuse so are carried by AT
-once in the cells, sugar can be transported to the blood and around the body
-cells contain mitochondria, carrying out respiration, providing energy needed for AT
how does active transport occur in root hair cells?
-concentrations of ions is lower in soil than inside the cell
-AT moves them into the cell
-they’re then transported to the xylem and moved to the leaf
-contains mitochondria, providing energy needed
