Photosynthesis
- Created by: poppyggggg
- Created on: 30-10-16 10:33
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- Photosynthesis
- Both plants and algae carry out photosynthesis
- It takes part in the chloroplasts, especially in the leaves
- During photosynthesis light energy is absorbed by the chlorophyll in the chloroplasts
- This energy is used to CO2 and H20 to glucose
- During photosynthesis light energy is absorbed by the chlorophyll in the chloroplasts
- It takes part in the chloroplasts, especially in the leaves
- Some of the glucose is used immediately for respiration but a lot of the glucose is converted into an insoluble starch and stored
- Test for starch using iodine
- Iodine solution is yellow-brown and turns blue-black in the presence of starch
- It will go blue-black if photosynthesis has occured
- Iodine solution is yellow-brown and turns blue-black in the presence of starch
- You must treat the leaves by boiling them in ethanol rinsing them to break down the waxy cuticle and remove the green chlorophyll colour
- Leaf adaptions
- Leaves are mostly broad which gives them a big surface area to absorb light
- They have air spaces to allow carbon dioxide to get into the cells, and oxygen to leave by diffusion
- Algae are aquatic so they are adapted to photosynthesise in water. They have a large SA to dissolve carbon dioxide in the water around them
- They have veins which bring water in the xylem and remove water products of photosynthesis through the phloegm
- 6CO2 + 6H2O (+light energy) ---> C6H12O6 + 6O2
- Both plants and algae carry out photosynthesis
- Limiting Factors
- Light
- A greater light intensity allows more photosynthesis to occur and for most plants, more light increases the rate
- Temperature
- As temperature rises, so does the rate of photosynthesis. However, photosynthesis is enzyme controlled and when temperaturesexceed 40-50°C, enzymes become denatured
- Carbon dioxide levels are increased at night because the plant respires but does not photosynthesis
- As light and temperature levels increase in the morning, carbon dioxide is used up
- C02 Levels
- On a sunny day, carbon dioxide levels are the most common limiting factor on a sunny day
- The atmosphere is about 0.04% CO2 and this is limiting
- Light
- The more a plant photosynthesises, the more biomass it makes and the faster it grows
- Farmers want their plants to grow as fast as possible
- It is almost impossible to control these factors out in the fields
- The environment can be artificially controlled using greenhouses or polytunnels (large greenhouse made of plastic
- These environmentsare much warmer, which means exotic fruits can be sold in the UK
- Large companies use big greenhouses to get the fastest rates
- Carbon dioxide levels will be increased during the day so it is not limiting
- Optimum temperature for enzyme action is maintained all the time
- Artificial lighting is used to prolong the hours of photosynthesis and increase light intensity
- Plants can be grown out of season and out of their normal habitat
- Large companies use big greenhouses to get the fastest rates
- These environmentsare much warmer, which means exotic fruits can be sold in the UK
- The environment can be artificially controlled using greenhouses or polytunnels (large greenhouse made of plastic
- It is almost impossible to control these factors out in the fields
- Farmers want their plants to grow as fast as possible
- However, the greenhouses have lots of software and cost a lot of money and use a lot of energy. However, turnover is faster so there are higher profits; crops are clean and unspoilt; there is no ploughing and crops can be grown in poor land; fewer staff are required
- Limiting factors are removed
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