Photosynthesis - AQA
Plants make their own food for thought victimization photosynthesis. The food that plants produce is critical, non but for the plants themselves, but for the other organisms that give happening the plants.
Requisite interoperable activity - light intensity and photosynthesis
The essence of light intensity connected the photosynthesis rate using an subaquatic being
The effect of light intensity on photosynthesis can be investigated in water plants. Use Cabomba or Elodea , which are oversubscribed in aquarium shops.
The plants will release bubbles of oxygen – a product of photosynthesis – which can exist counted.
A lamp with an LED lightbulb is set in the lead at antithetic distances from the plant in a beaker of water:
- an LED bulb is best as this will non raise the temperature of the water
- sodium hydrogencarbonate – chemical formula NaHCO 3 – is added to the water to provision carbon dioxide – a reactant in photosynthesis – to the plant
- the candlepower is proportional to outdistance – IT will fall as the distance away from the bulb increases – so light intensity for the investigation can represent varied aside ever-changing the outdistance from the lamp to the plant
The bubbles produced over one minute periods are recorded.
Direct
To investigate the effect of candlepower along the rate of photosynthesis.
Method acting
- Set up a simmering tube containing 45 Cm 3 of sodium hydrogencarbonate solution (1%). Grant the tube to represen a couple of minutes and shake to disperse any air bubbles that might mold.
- Cut a piece of music of the pondweed, Cabomba . The pondweed should be 8 cm long.
- Use forcepts to shoes the Elodea in the boiling tube carefully. Make sure that you don't damage the pondweed, or causal agent the liquid to bubble over.
- Position the boiling tube so that the pondweed is 10 curium away from the light source. Allow the simmering thermionic valv to stand for five minutes. Count the number of bubbles emerging from the mown end of the stems in united careful. Repeat the calculate 5 multiplication and record your results.
- Calculate the average number of bubbles produced per minute. Repeat the experiment at different distances away from the light source.
Variables
- Independent variable – distance from the light source/short intensity.
- Myrmecophilous unsettled – the number of bubbles produced per minute.
- Hold in variables – concentration of sodium hydrogencarbonate solution, temperature, victimisation the same small-arm of Genus Cabomba pondweed each time.
Risks
Care must beryllium taken when using water near electrical equipment. Ensure that your hands are unproductive when handling the lamp.
Extension activities
The volume of oxygen produced could be measured by collecting the gas produced in a gas syringe.
The changes in the oxygen engrossment in the water could be measured using data logging equipment.
You could investigate the gist of different wavelengths of light on photosynthesis.
Use chestnut-coloured acetate filters to investigate the effects of the blue, green and cherry-red parts of the spectrum on photosynthesis.
The effect of chlorophyl
The effect of the comportment surgery absence of chlorophyl on photosynthesis can personify investigated victimization a variegated implant. Variegated plants deliver regions of their leaves with, and without, chlorophyll.
Only those areas of the leaf with chlorophyll photosynthesise. They will test positive for starch, which is built up from the glucose produced.
- The leaf of a varicolored Pelargonium is dropped in simmering water to killing and preserve IT
- The leaf is left for 10 transactions in tropical ethanol in a boiling tube. This removes the chlorophyl
- The leaf is dipped in boiling water to soften it
- The leaf is circularize call at a Petri cup of tea and covered with iodine solution
- The areas that had the chlorophyll stain achromatic. The areas that had no more chlorophyl remain pale
Risks
Care must be taken when using boiling fermentation alcohol. Make a point that no Bunsen burners are turned happening as the ethanol is extremely flammable.
tasha is testing the effect of blue colored light
Source: https://www.bbc.co.uk/bitesize/guides/zs4mk2p/revision/5
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