B8: Photosynthesis Flashcards
how are plants adapted to photosynthesise?
- leaves are broad - increase SA FOR LIGHT
- thin leaves - decrease diffusion distance
- chlorophyll to absorb light
- have veins which bring water from xylem to cells/ remove products of photosynthesis in phloem
- air spaces allow co2 into cells/o2 to leave by diffusion
- grad cells open/ close stomata to regulate gas exchange
photosynthesis equation?
carbon dioxide + water —> glucose + oxygen
how do plants use glucose ?
RESPIRATION- glucose is broken down using oxygen to provide energy
BUILT INTO STARCH - glucose is soluble in water - can affect water potential of plant (affecting osmosis)
starch is INSOLUBLE - won’t affect osmosis
CELLULOSE - builds cellulose which strengthens cell wall
AMINO ACIDS - combine sugars from nitrate/mineral ions to make amino acids - used to make proteins for plant
LIPIDS - lipids are an energy store in cells/cell walls stronger
- can be energy store in seeds to provide food for new plant to respire/germinate
REQUIRED PRACTICAL : Photosynthesis
- use lamp. pondweed, metre stick , beaker/boiling tube
- fill boiling tube with water and SODIUM HYDROGEN CARBONATE to ensure enough co2
- put pondweed in tube/push to bottom
- put boiling tube in beaker of water to ensure light’s heat doesn’t affect experiment
- put beaker/tube almost touching lamp for 5 mins.
- start stopwatch and count no. bubbles in 15 secs. multiply by 4 and record results
- keep moving beaker at different distances from light.
what is a limiting factor and 3 limiting factors of photosynthesis?
- things that can be in short supply so plants can’t photosynthesise as fast as they can
LIGHT - no light - photosynthesis will stop
TEMPERATURE - too cool, photosynthesis decreases, too hot, enzymes denature/it slows down process
C02 -
