plant transport Flashcards
why do plants need a transport system
to carry materials around the plant for various metabolic reactions
give 3 materials carried in the plant transport system
water, co2, minerals, carbohydrates
what are the adaptions of a root hair for osmosis
thin walls, large surface area
how does water enter a root
osmosis
by what process does water move from the root to the xylem
diffusion- it passes through the ground tissue until it reaches xylem
give the two mechanisms which move water upwards in a plant
root pressure and transpiration
explain root pressure in relation to water’s upwards movement
water moving into the roots through osmosis builds up pressure in the root, pushing water into the stems
explain transpiration in relation to water’s upwards movement
is the loss of water vapour by evaporation through stomata of a leaf. when water evaporates from the leaves, it pulls the water molecules up the plant. can be explained using cohesion-tension model
who discovered the cohesion-tension model
John Joly and Henry DIxon
explain cohesion in the cohesion tension model
means that similar molecules are attracted to each other- this means that there is constantly a column of water in the xylem
explain adhesion in the cohesion tension model
means there is an attraction between different substances
explain three different ways in which water loss is controlled in a plant
waxy cuticle- covers some leaves, doesnt allow water to pass. leaves have adaptions- e.g cacti have thin spiny needles. stomata- undersurface of a leaf,close at night and open at day
what energy do minerals use to move into the root hairs
active transport
how might a root be modified for food storage?
tap roots in dicot plants often become swollen and fleshy with starch. e.g carrot
how might a stem be modified for food storage
i.e potatoes- underground stem system. tips of roots called tubers become swollen with starch
