• 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
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19
  20. 20
    20
  21. 21
    21
  22. 22
    22
  23. 23
    23
  24. 24
    24
  25. 25
    25
  • Level: GCSE
  • Subject: Science
  • Document length: 5744 words

Investigate the factors, which affect photosynthesis.

Extracts from this document...

Introduction

Introduction Aim My aim in this coursework is to investigate the factors, which affect photosynthesis. My aim is to confirm which factors increases or decreases the rate of photosynthesis. The factors are * Carbon dioxide, * Chlorophyll * Light intensity * Water The building-up of complex food molecules from simpler substances is called a synthesis and it needs enzymes and energy to make it occur. Enzymes those are present in the plant's cells and the energy for the first stages in the synthesis comes from sunlight. The process is, therefore, called photosynthesis ('photo' means light). Photosynthesis is the main type of auto tropic nutrition. There are two fundamentally different methods of nutrition. Animals and certain other organisms take in ready-made organic substances, this is known as heterotrophic nutrition. Other organisms, notably plants, take in simple inorganic substances which they then build up into complex organics substances, this is known as auto tropic nutrition. The importance of photosynthesis Heterotrophs, including humans, all depend on photosynthesis for making their food. The manufacturing of sugar (starch) during the process of photosynthesis is astounding. For example: a hectare of maize can convert as much as 10 000 kg of carbon form carbon dioxide into the carbon of sugar in a year, giving a total yield of 25 000 kg of sugar per year. This example is a fact that was ascertained by my previous Biology teacher. For photosynthesis to take place a plant requires carbon dioxide, water, light, chlorophyll and a suitable temperature. The necessity for these factors can be demonstrated by simple experiments either on whole plants or single leaves. The main product that is produced during the process of photosynthesis is sugar, although this is often built up into starch for storage. As an indication of whether or not photosynthesis has been taking place, leaves are tested for starch. At first the plant has to be de-starch a plant. ...read more.

Middle

I have also gained knowledge that carbon dioxide is a limiting factor. It reduces the rate of photosynthesis. Evaluation My prediction that I had made in the planning was correct, as we know that the leaf that contained a carbon dioxide reducing compound, there were no starch present after conducting the starch experiment. Hence, I had stated that photosynthesis would not take place if there were no carbon dioxide; therefore this is accurate, as no photosynthesis had taken place in this part on the leaf, whereas in the other there were signs of starch, which shows that photosynthesis was taking place. During the experiment there were no problems or errors. The two compounds Soda lime and Sodium Hydrogen Carbonate, which were used to reduce the amount of carbon dioxide and slowly break up to produce carbon dioxide respectively. These two substances/solutions were left for several hours to make sure that they would take affect. The 2 conical flasks act as a mini habitat, giving the effect of a green house effect, consequential in the increase in temperature and increase of light intensity, the factor had very little effect on the experiment, but it would effect a more elaborate experimentation. The rate of depletion in carbon dioxide influences the rate of photosynthesis and makes it stop at a certain time limit. Hence it is a limiting factor. Improvements During this experiment many bits and pieces could have been added in, this would have given us an accurate result. The following points show some improvements that could have been made: * To make sure the rubber bungs in both conical flasks were air tightened, they been injected with Vaseline to make sure that the gap was airtight and no gases would enter or escape the conical flask. This has been shown on the diagram that was shown at the beginning of this experiment. Factors that affect photosynthesis. ...read more.

Conclusion

* As soon as the first bubble appears the counting begins. * The numbers of bubbles produced every 5 minutes are recorded. * The same steps are taken into deliberation, but this time the temperatures rise till 540c. Results The following table shows the three trails and the average number of bubbles that were recorded during the experiment: Temperature (0c) Trial 1 (number of bubbles) Trial 2 Trial 3 Average 35 238 240 242 240 37 402 394 398 398 40 480 479 481 480 43 540 541 539 540 53 - - - - Using the formula mentioned above, I found out the rate of photosynthesis, which was much easier to plot on graph paper: Temperature (0c) Rate of photosynthesis (Bubbles/Sec) 35 4 37 6.633 40 8 43 9 53 - Graphs The tables above have been plotted on the graphs on the next few pages: Conclusion The prediction I had made was correct. As the temperature increased the rate of photosynthesis increased as well. But as I had mentioned that it has a limit, I did nto seem to come across a limit. Evaluation Counting bubbles was an indirect method of measuring the rate of photosynthesis. The following points show why the experiment was not so accurate: * The pressure within the water may have affected the emission of bubbles. * The size of the leaf may have affected readings due to the number of stomata pores. * The bubbles did not have a fixed size. The sizes were variable. * The pondweed was contained in a microenvironment; the test tube may have affected the emission of bubbles. * The Elodea had many branches; their branches may have trapped oxygen bubbles beneath them. * Some of the bubbles were expected to have merged together. Therefore there were not a large number of bubbles. * KHCO3 was added at the beginning of the experiment and was not changed at all. KHCO3 affected the first few results but may not have had the same effect upon the last result because it had been used up. ...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

    How the molar concentration of NaHCO3 (Sodium Hydrogen Carbonate) affects the rate of photosynthesis ...

    5 star(s)

    In the following graph, it is clear that there is a general pattern that backs up this fact (that as the concentration of NaHCO3 is increased, the number of bubbles produced also increases). Using the table above, the existing relationship is clear with the only exception to the pattern occurring

  2. Marked by a teacher

    Light Intensity and Photosynthesis.

    4 star(s)

    Set up a lamp at a set distance from the plant, ensuring that this distance is from the filament of the lamp to the actual pondweed, rather than the edge of the beaker.

  1. Marked by a teacher

    Testing Starch in a (Variegated) Leaf - Lab Report

    3 star(s)

    * Iodine reagent was used to test for the presence for starch. Qualitative Data: * The leaf became soft after placed in the hot water * After the leaf sample was placed in the alcohol, the green colour on the leaf dissolved in the alcohol, turning the colour of alcohol from transparent to green.

  2. Marked by a teacher

    Biology Coursework : Rate of Photosynthesis

    3 star(s)

    Water- Water is required in the photosynthetic reaction. When plants lack water, their stomata close to prevent further water loss. At the same time, closing the stomata cells doesn't allow CO2 to diffuse into the leaf. Water is also therefore, linked to the carbon dioxide factor.

  1. GCSE Biology - Photosynthesis Coursework

    I also therefore needed a way of accurately measuring the light intensity, and I did this using a photometer. I recorded the lux reading (unit of light intensity) at each distance. I got the following results: Results of preliminary experiment Distance Light intensity No.

  2. How temperature affects the rate of photosynthesis.

    This reaction is catalysed by a water splitting enzyme present in the photosystem itself. H2O 2H+ + 2e- + 1/2O2 These electrons produced during the photolysis of water are absorbed by P680 and stabilise it. The hydrogen ions combine with the electrons released from photosystem I (P700)

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

    Hypothesis: The more carbon dioxide there is, the more oxygen will be produced therefore increasing the rate of photosynthesis. This will take place until saturation, which is when the reaction will be taking place at its maximum. It is known from theoretical study that if the carbon dioxide is doubled,

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

    This is important in reflecting success only if my prediction was sensible and logical. Just as important is where the experiment was not a success and why. This photosynthesis investigation was probably not performed as accurately as it could have been due to some controllable and uncontrollable conditions.

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