transport system
plants
absorption of water and mineral salts in roots
- soil has higher concentration of water than root hair cell, and thus water from soil moves into root hair cell through osmosis
- soil contains water and mineral salts. the root hair cells takes in water by osmosis, and it also takes in mineral salts
xylem
transports water, inside tube for the stem
water + mineral salts ➡ root hair cells ➡xylem vessles ➡ other parts of plant
phloem
transports food, outside tube for stem
Carbon dioxide ➡ sugar in leaf ➡ phloem vessels ➡ other parts of plant
diffusion
diffusion is the net movement of substances except water from a region of higher concentration to a region of lower concentration with or without a membrane
diffusion is fastest in gas and slowest in solids
example in solutions
10% sucrose solution beside 2% sucrose solution
solution A has a higher concentration of sucrose molecules than solution B. Thus more sucrose molecules move from A to B than from B to A. (diffusion will occur until both solutions have same amount of sucrose molecules)
solution B has a higher concentration of water molecules than solution A. thus more water molecules move from B to A than from A to B. (osmosis)
example in plants
concentration of oxygen in airspaces of stomata is higher than outside of the leaf, so oxygen diffuses out
concentration of carbon dioxide in air spaces of stomata is lower than on the outside of the leaf and thus carbon dioxide diffuses in.
osmosis
osmosis is the net movement of only water molecules from a region of higher concentration to a region of lower concentration through partially permeable membrane
example in solutions
10% sucrose solution beside 5% sucrose solutions
solution A has a higher concentration of sucrose molecules than solution B. this means that solution A has a lower concentration of water molecules than solution B. however the sucrose solution is too big to move across the pertially permeable membrane
solution B has a higher concentration of water molecules than solution B. water molecules are small enough to pass through the partially permeable membrane, hence water molcules move from solution B to solution A.
there is a net movement of water molecules. eventually both solutions have the same concentration of sucrose and water molecules. volume of A rises while b falls
now theres no net movement of water molecules
human transport system
veins
carries blood towards heart
artery
arteries carries blood away from heart
capillaries
capillary walls are one cell thick to allow quick diffusion of nutrients and oxygem from the blood to tissue cells. waste substances can also move from tissue cells to blood in capillaries
blood
acts as transport medium
plasma
transport digested food from small intestine to other parts of body
remove carbon dioxide and other waste substances produced by body cells
transport other substances such as hormones
white blood cells
platelets
helps to fight infections
form blood clots when theres bleeding