5 Plant nutrition Flashcards
Define photosynthesis
the process by which plants manufacture carbohydrates from raw materials using energy from light.
Balanced symbol equation for photosynthesis
6CO2+6H2O→C6H12O6+6O2.
Word equation for photosynthesis
Carbon dioxide + water —> (light energy) glucose + oxygen.
Role of chlorophyll
Absorbs light to transfer light energy into chemical energy in molecules for synthesis of carbohydrates.
Storage of carbohydrates made in photsynthesis
Converted into starch. Starch is insoluble so not affected by osmosis. Large molecules with lots of glucose molecules joined together.
Some converted to sucrose. this is soluble but not as reactive as glucose so easily carried around the plant in solution.
Describe gas exchange in plants
Plants respire as well as photosynthesise. At night plants only respire. They take in CO2 and release O2.
Role of waxy cuticle
Covers leaf on upper surface, prevents loss of water from epidermal cells and helps from drying out too quickly.
Role of upper epidermis
Transparent, allows as much light as possible to reach the photosynthesising cells in leaf.
Role of palisade mesophyll cells
Most photosynthesis takes place here. Tightly packed together in upper half of leaf to receive as much sunlight as possible.
Role of chloroplasts
Contain chlorophyll, concentrated in palisade mesophyll cells.
Role of spongy mesophyll cells
Air spaces around to allow gases to be exchanged.
Role of stomata
Allow movement of gases in and out of leaf.
Role of vascular bundle
Forms the veins in stem and leaf. Thick cell walls of tissue to help support stem and leaf.
Role of phloem
Transports sucrose away from the leaf.
Role of Xylem
Transports water and minerals to leaf from roots.
