• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

How light intensity affects Photosynthesis.

Extracts from this document...

Introduction

P l a n Photosynthesis is the chemical process, which takes place in every green plant to produce food in the form of glucose. Plants use water and carbon molecules and the suns energy to join together to form glucose, which is sent around the plant to provide food. Cells in the root or stem can use the glucose to make energy, if the plant does not need to use all the glucose immediately then it is stored which is difficult because glucose is hard to store in water. Plants have adapted with this problem by joining hundreds of glucose molecules together to make a starch compound. Starch does not dissolve in water very well so it makes a better food store. Photosynthesis takes the palisade mesophyll cells in the leaf of a plant. It is these cells that contain the green chloroplasts and are very well adapted to their task. They are near the upper side of the leaf where they can obtain the maximum amount of light, they are packed very closely together and contain a green pigment called chlorophyll, and these absorb the sunlight and therefore help greatly to the production of photosynthesis. The cells are arranged like a fence, these help the energy entering the surface (top) of the leaf to travel a long way through the palisade cells. To obtain the most sunlight as possible, leaves have a large surface area and the more sunlight the plant receives, the better it can photosynthesise. ...read more.

Middle

* Turn on light source (lamp) at suitable distance from plant, measured by the metre rule so it gives more accuracy. * Measure light intensity by lightmeter and record observations on the face of the lightmeter. * Next apply the light to test tube, with plant inside it (upside down) which is in water. The plant must be upside down because then the bubbles can be seen quicker and easily therefore resulting in a far more reliable experiment. Also the lamp may be moved up and down constantly so the light reaches the plant but it is preferred to leave the lamp alone. This is due to the fact that if you move the lamp then you are; then, changing its distance from the plant and therefore altering the amount of light intensity the plant receives which will make the experiment unreliable. Patiently wait until bubbles can be seen, then count and record total amount of bubbles until a given time limit (1-minute) is reached. * Record observations and repeat two more times and take average to give a concordant of reliable results. * Continue until five light intensity results, which are repeated three times each, have been observed and recorded (also averaged). Record total amount for each experiment. The following safety precautions had been considered; electricity from the light source and water from the test tube. It would be very dangerous if water and electricity would coincide with one another, as this would provide some injury to a student, as water is quite a good conductor. ...read more.

Conclusion

this is an anomaly. Another anomaly was in the first experiment for '50cm' from plant, as its value was too high compared to the remaining two results. This was dealt with easily as I took the concordant value. There were anomalies because the reading of the bubbles could be incorrect due to human error. Also the amount of carbon hydroxide which was put in might not have been the exact same thus causing anomalies as this affects the process photosynthesis due to carbon dioxide being one of the main component for photosynthesis. Another factor is that the Canadian pondweed I used was not the same one I used throughout the whole experiment. This would certainly cause anomalies as different plants have different abilities to produce photosynthesis. The conclusion is reliable because I have quite accurate and reliable measurements with good scientific understanding applied to it. My method was very good and it provided some very good results. If I re-did the experiment I would use the same plant throughout the experiment, use the exact amount of carbon hydroxide and also take an average after five results, therefore a total of twenty-five experiments. An alternative way of measuring the same outcome variable is to use a manometer. This would have been much better and very accurate in measuring the rate of photosynthesis. This would overcome problems such as counting the bubbles and less chance of human error. The experiment would have provided very reliable results. Here is a diagram of what I would do. Husnain Ali Biology Coursework: How light intensity affects the rate of photosynthesis 1 ...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)

    light intensity will have no further effect on the rate of photosynthesis. There will be another limiting factor, in this case probably temperature or carbon dioxide." On my graph, I can't see that curve levels off. This means that my independent variable didn't cover the whole range of value, which my prediction refers to.

  2. Marked by a teacher

    Light Intensity and Photosynthesis.

    4 star(s)

    The preliminary experiment will, however, give me a best fit curve to which I can compare my main graph, and also points at either end of my results at which it is clear to see light intensity has little or no effect.

  1. How Light Intensity Affects the Rate of Photosynthesis

    Because of this my results are not very accurate as a number of variables could have influenced the experiment:- > Light - The lamp was not the only light source as it was done in a lit room so the pondweed was already photosynthesising.

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

    The thermal energy breaks the hydrogen bonds holding the secondary and tertiary structure of the enzyme together, so the enzyme (and especially the active site) loses its shape to become a random coil. The substrate can no longer bind, and the reaction is no longer catalysed.

  1. Investigate the effect of light intensity on the rate of photosynthesis in an aquatic ...

    I could have done this by means of investigating the amount of starch present in the leaf of the plant (Glucose is converted promptly into starch by plants as it is insoluble, which makes it much better for storing within the leaf).

  2. An Investigation into Species Diversity with distance along a Pingo.

    This test was used because it tests observed data to the theory that there should equal number of species and an equal amount of moisture along the pingo, this is the 'expected' number.

  1. How temperature affects the rate of photosynthesis.

    The light-dependant reactions: The light independent reactions take place in the grana of the chloroplast. These reactions include: * Synthesis of ATP from ADP in photophosphorylation. * Splitting of water by photolysis to give hydrogen ions * Production of reduced NADP Photophosphorylation of ATP can be cyclic and non cyclic,

  2. How light intensity affects the rate of photosynthesis

    no light at all, then no photosynthesis would occur; even though there is plenty carbon dioxide and the perfect temperature, there is still no photosynthesis as one factor is not fulfilled. I have drawn a graph to show how the rate of photosynthesis increases to a certain level until a limiting factor stops it going any further.

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