Plants Flashcards
Transpiration def
The movement of water and minerals into the root, up the stem and into the leaf through the xylem vessels
Translocation def
The movement of sucrose (made from glucose in photosynthesis) in the phloem vessels. It can travel in both directions to all parts of the plant
Process of transpiration
Water evaporates by diffusing through the stomata. The water lost from the leaf is replaced by water from the xylem via osmosis. As water evaporates, water is pulled up the xylem because water is cohesive (sticks to other water molecules). Water enters the plant through osmosis from the soil to the root hair cells
Capillary action
When water molecules stick together (cohesion) and water evaporated pulls water up the xylem
Photosynthesis def
An endothermic reaction that uses light energy to react carbon dioxide and water to produce glucose and oxygen
Adaptations of root hair cells
Large vacuole (to maintain water levels), lots of mitochondria (for respiration for energy for active transport of minerals), thin cell wall (short path for water and minerals for diffusion and osmosis making rate faster, large surface area (allows more space for nutrients to be absorbed
Nitrates
Needed for protein synthesis
Magnesium
Needed for chlorophyll production
Structure of xylem
Lignin dead cells transport water and minerals through plant from roots to stems to leaves
Structure of phloem
Living cells use energy to transport sucrose around the plant
Limiting factors of photosynthesis
Light intensity, temperature and CO2 concentration
Plant hormones used in fruit ripening
Ethene - gas is used to ripen the fruit, it is picked unripe so that it is easier to transport without damaging, can be kept for longer in cold storage without going off
Plant hormones used in seedless fruit
Gibberellins - cause some plants to produce fruit without pollen, sprayed on plants to make them produce bigger fruits, cause formation of seedless fruit and flowers, germination
Plant hormones used in rooting powders
Auxins - cause plant cuttings to develop roots quickly, large numbers of identical plants can be produced quickly rather from one seed
Plant hormones used in weed killers
Artificial auxins - kill plants with broad leaves (not narrow) as they take the most sunlight and prevent other plants from photosynthesising and surviving making the plant grow uncontrollably and eventually killing it, the farmers can kill weeds without affecting crop
