plant cell diversity Flashcards
what are palisade leaf cells adapted for?
how are they specialised?
-adapted for photosynthesis
-contain many chloroplast so can absorb lots of sunlight, thin walls so co2 can diffuse easily into cell, large vacuole to push chloroplast to surface
what causes guard cells to change shape?
how does their structure allow them to open and close stomatal pores?
-ATP pewered proton pump transports hydrogen ions out of cell= potassium ions diffuse into cell down electorchemical gradient= decreases water potential = osmosis of water =more turgid resulting in gaurd cells being open
-this outer walls and thickened inner walls = allow guard cells to bend/ open stomatal pores for gas exchange
how does the structure of root hair cells adapted to its function?
why does water enter?
-absorb water and mineral ions from the soil
-large surface area for absorption and thin permeable cell wall for entry of water and ions (osmosis and active transport)
-extra mitochondria for active transport
-water follows mineral ions to increase water potential
what are the 3 different plant tissues?
-epidermal tissue
-meristematic tissue
-vascular tissue (transport system)
describe epidermal tissue
-equivalent to epithelial in animals
-protective layer of flattened cells
-lacks chloroplast
-some have waxy cuticle to reduce water loss
describe the meristematic tissue
-contain stem cells
-found in the root and shoot tips and cambium of vascular bundles
-divide by mitosis and differentiate
-thin walls, little cellulose, no chloroplast, no large vacuole
describe vascular tissue
xylem- carries water and minerals from roots to all parts of plant
-phloem- transfers sugars (sucrose) to parts that do not photosynthesis such as roots, flowers, and growing shoots
describe the features of xylem as a differentiated outcome derived from a common stem cell in meristem (cambium)
-lignin deposited in their cell walls to reinforce and water proof them, but kills the cells
-ends of walls break and cells fuse together= long hollow tubes
-non living tissue
describe the features of phloem as a differentiated outcome derived from a common stem cell in meristem (cambium)
-phloem sieve tubes
-sieve tube elements joined end to end = long hollow structures
-sieve plates
-companion cells form wth sieve tube elements and linked by plasmodesmata, provides life support, energy to phloem
what are the four plant organs
what are their main functions?
-leaf= photosynthesis
-root = anchorage in soil, absorption of mineral ions, and water, storage of carbohydrates e.g carrot
-stem = support, holds leaves up, transport of water and products of photosynthesis
-flower = asexual reproduction
