• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9

Effects of temperature and carbon dioxide on photosynthetic rate in Elodea.

Extracts from this document...

Introduction

A2 Biology- Effects of temperature and carbon dioxide on photosynthetic rate in Elodea. Aim: to investigate the effects of temperature and carbon dioxide on the photosynthetic rate of Elodea. Background knowledge: Photosynthesis is the use of light energy from the sun to fix carbon dioxide i.e. converted to sugars. These sugars can then be converted into other essential substances- fats and proteins etc.- that plants need to live and grow. Photosynthesis can be represented using the following equation: 6CO2 + 6H2O ? C6H12O6 + 6O2 The light independent stage occurs in the stroma. Firstly CO2 combines with a 5C compound called ribulose bisphosphate. This reaction is catalysed by the enzyme RuBPC. The 6C compound formed immediately splits into two molecules of glycerate-3-phosphate (GP). The GP molecules are converted into molecules of triose phosphate (TP) using energy from ATP and the hydrogen atom from NADPH. Some of the TP is used to regenerate RuBP. Finally the rest of the TP is used to produce other essential substances that the plant needs- fats, proteins etc. As light intensity is increased, photosynthesis begins, and some carbon dioxide from respiration is utilised in photosynthesis and so less is evolved. With a continuing increase in light intensity a point is reached where carbon dioxide is neither evolved nor absorbed. At this point the carbon dioxide produced in respiration exactly balances that being used in photosynthesis. 'This is called the compensation point'1. 'Further increases in light intensity result in a proportional increase in the rate of photosynthesis until light saturation is reached'2. Beyond this point further increases in light intensity have no effect on the rate of photosynthesis. If, however, more carbon dioxide is made available to the plant, further increases in light intensity do increase the rate of photosynthesis until light saturation is again reached, only this time at a higher light intensity. ...read more.

Middle

Remember the concentration of NaHCO3 must remain constant throughout this experiment. Risk assessment: * Wear safety goggles and take care when handling chemicals, such as NaHCO3 solution, to prevent any foreign particles from entering the eye. * Tie long hair back if using Bunsen burner to prevent obstruction of sight, and to prevent accidents. * Care should be taken when handling the sodium hydrogen carbonate solution as it maybe irritating to eyes and skin. * Take care when handling the Bunsen burner as you may burn yourself. * Do not sit down during the experiment, especially when Bunsen burners are alight, and keep all chairs/stools out of the way as these will slow down reaction time, in case of an emergency. * Care should be taken when handling the scalpel, as it is a sharp object and can cause injury if mishandled. * Take care when handling the beakers after heating the contents, as they may be hot. * To avoid accidents, wipe any spillage immediately and maintain organization throughout the experiment. * While the Bunsen burner is not in use ensure that the safety/yellow flame can be seen. Results: Tables showing the volume of O2 produced at different concentrations of NaHCO3 and different temperatures. Temperature 10?c. Concentration of NaHCO3 solution, in mol dm3. Volume of O2 produced, in cm3. 0 0.12 0.10 0.10 0.10 0.10 0.00 0.01 0.40 0.46 0.38 0.36 0.38 0.44 0.025 0.63 0.63 0.65 0.62 0.62 0.63 0.60 0.55 0.55 0.05 0.62 0.62 0.50 Temperature 20?c. Concentration of NaHCO3 solution, in mol dm3. Volume of O2 produced, in cm3. 0 0.25 0.36 0.20 0.20 0.22 0.20 0.01 0.80 0.86 0.75 0.72 0.75 0.88 0.025 1.30 1.30 1.25 1.25 1.25 1.25 1.20 1.18 1.10 0.05 1.20 1.20 1.00 Temperature 30?c. ...read more.

Conclusion

Modifications: Limitations. * The room temperature may fluctuate. * The concentration of carbon dioxide in the water may be reduced during experiment. * The rate of gas evolution is not consistent. * There are other light sources, which may interfere with the results. * Artificial light will increase temperature, as a 60watt bulb will be used, some energy will be lost as heat energy. * Are the bubbles being observed actually oxygen? Setting up the apparatus and placing it in a water bath may overcome the first error. Doing so will ensure that a constant temperature is maintained throughout the experiment. To avoid other light sources interfering with the experiment shelter the apparatus up so that the pondweed only receives light from the table lamp. To ensure consistency of gas evolution when changing to a new condition, the plant should be equilibrated for at least 10 minutes before taking any readings. Using a dilute sodium hydrogen carbonate solution ensures a constant supply of carbon dioxide to the pondweed, avoiding fluctuation of carbon dioxide concentrations. To test for presence of oxygen simply lower a glowing splint into the test tube containing the gas; if the splint relights this indicates that oxygen is present. Using this test increases reliability of the results. The presence of the lamp may cause the temperature to increase; to prevent this from happening ice can be used to maintain a constant temperature. Further experiments could be implemented to test other factors that may have an affect on the rate of photosynthesis. Light intensity has been found to have an affect on photosynthesis. This can be investigated by placing a light at varying distances from the elodea plant and recording the number of bubbles produced. Other experiments in this area could also include testing the rate of photosynthesis with different amounts of chlorophyll in the plants. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Marked by a teacher

    An investigation into the effect of light intensity on the rate of photosynthesis of ...

    5 star(s)

    I think this may because error of counting. Or it may because the error of the distance measuring. Explanation of trends As the intensity of light increased, so would the rate of photosynthesis. The elements that are needed for photosynthesis are carbon, hydrogen and oxygen. The carbon dioxide in the water is the source of carbon.

  2. Marked by a teacher

    Investigating Factors Affecting the Rate of Photosynthesis.

    5 star(s)

    This should boil the ethanol) * When all the chlorophyll (green colour) is removed and the cuticle is broken down, take the leaf out and dry on white board. * Put iodine on leaf * Where there is starch produced by photosynthesis, it will turn blue/black but if there's no starch, it will just stay white.

  1. Marked by a teacher

    Investigate the relationship between wavelength of light and the rate of photosynthesis using pondweed.

    3 star(s)

    A number of factors could have affected the experiment impairing the results. Different pondweed was used in the 1 st and repeat experiments, which could have had implications on the results.

  2. Experiment to investigate the effect of Carbon Dioxide on the Rate of Photosynthesis

    The distance the lamp is from the plant (light intensity) will be kept the same, as light is also a factor, which affects the rate of photosynthesis. Light affects the rate because if there is more light it is like giving the plant more food and therefore it will have more energy.

  1. Investigating the effect of temperature on the rate of photosynthesis

    Photosynthetic pigments trap light energy. Different pigments absorb different wavelengths of light. The photosynthetic pigments of higher plants form two groups: chlorophylls and the carotenoids, each absorb different wavelengths of light so that the total amount of light absorbed is greater than if a single pigment were involved.

  2. Experiment to Investigate the Effect of Temperature on the Rate of Photosynthesis in Elodea.

    Light is the driving factor in photosynthesis, as with no light photosynthesis would not take place. The more light there is, the more light is absorbed by the two photosystems. The means a greater amount of electron excitation and consequently more ATP and NADPH is synthesised in the light dependant reaction.

  1. Investigate the factors, which affect photosynthesis.

    Fair test In order for the experiment to be a fair test and the results to be accurate as possible, it is convenient to do the following points: * The conical flasks should be airtight. * When the starch test will be taken under consideration, the same amount of iodine should be used to test both leaves.

  2. Investigation To Find The Effect Of Temperature On The Rate Of Photosynthesis Of Elodea.

    This is because after the enzymes reach their optimum temperature, they become denatured. Their shape is changed and they can no longer perform their function, which is in this case, combining hydrogen and carbon dioxide. This meant that the optimum temperature for the enzymes in the elodea is between 26-30?C.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work