B8- Photosynthesis Flashcards
Photosynthesis word equation
Carbon dioxide+water—–>Glucose+oxygen
Photosynthesis symbol equation
6CO2 + 6H2O—–> C6H12O6 + 6O2
Where does photosynthesis occur?
Chlorophyll
What type of reaction is photosynthesis and why?
Endothermic, uses energy (light) from the environment
What 2 ways is glucose used?
Some used immediately for respiration. Some converted to insoluble starch and stored.
3 Leaf adaptations
Broad- large sa for light to fall on
Contain chlorophyll- absorbs light
Guard cells- open and close stomata to regulate gas exchange
3 factors that limit photosynthesis
Temperature, carbon dioxide, light intensity
Light affecting rate of photosynthesis
As light intensity increases, photosyn increases until max level reached, another factor is limiting
Temperature affecting rate of photosynthesis
As temp increases, photosyn increases until optimum temp. After the enzymes denature and rate decreases
Carbon dioxide affecting rate of photosynthesis
As carbon dioxide levels increase, photosyn increases until max level reached. Another factor is limiting
How to investigate the effect of light intensity on photosynthesis.
-Fill boiling tube with sodium hydrogen carbonate solution, place pond weed with cut end up
-Tube 10cm away from LED light, wait to acclimatise
-Count bubbles in 1min, repeat, calculate mean
-Repeat at different distances and plot graph
Better method of light intensity affecting photosynthesis
Place inverted funnel on top of plant with a measuring cylinder to measure oxygen produced
Inverse square law
1 (over)
distance squared
How can glucose be stored in plants?
2 things this is used for?
Stored as insoluble starch
Produces an energy store when the light levels are low
Produces tubers and bulbs for storage for winter
What 4 things can glucose immediately be used for?
Respiration
Built into cellulose to strengthen cell walls
Produce amino acids for protein synthesis
Stored as lipids (fats)
What is a polytunnel and why are they used?
A giant greenhouse
Allows plants to fruit and flower earlier, higher yield
Grow crops that can’t grow in UK eg. peaches
What are hydroponics and why are they used?
Greenhouses with the environment controlled by computers
Plants grow quicker and are less spoilt in perfect conditions, but expensive
Greenhouse economics
Ads and Dis
Ads- higher yield, needs less staff, cleaner crops
Dis- High start up costs, expensive equipment
