This experiment involves using a photosynthometer to investigate how temperature affects the rate of photosynthesis in the elodea.
Contents:
Page 2 Abstract
Page 3 Aim and Introduction
Page 8 Prediction
Page 9 Preliminary Investigation
Page 12 Apparatus and Justification
Page 13 Proposed Method
Page 15 Analysis of Variables:
Page 16 Reliability
Page 17 Individual Results
Page 18 Class Results
Abstract:
This experiment involves using a photosynthometer to investigate how temperature affects the rate of photosynthesis in the elodea. Using this apparatus makes it possible to measure the rate of oxygen production by the elodea specimen, while varying the temperature. Bubbles of oxygen molecules are collected in a capillary tube of the apparatus. When a suitable volume of gas has been collected in five minutes, it can be drawn (by a syringe) as bubbles along side the scale and the length of the bubbles measured. The volume of oxygen produced is calculated by multiplying the length of the bubble(s) by pie, which is then multiplied by 0.82 (radius of the tube).
The results from this experiment have revealed that an increase in temperature correlates to an increase in the rate of photosynthesis up to 45o C. Beyond this temperature, the rate of photosynthesis starts to decrease in a non uniform manner.
Aim: To investigate how temperature affects the rate of photosynthesis in the elodea specimen.
Introduction:
Photosynthesis is trapping or fixation of carbon dioxide followed by its reduction to carbohydrate (triose phosphate), using hydrogen from water. The necessary energy comes from the absorbed light energy.
Light
nCo2 + nH2O ======> (CH2O)n + O2
At high light intensities the rate of photosynthesis increases as the temperature is increased over a limited range. At low light intensities, increasing the temperature has a little effect in increasing the rate of photosynthesis1. Research has suggested that photochemical reactions (reactions dependant on light) are generally not affected by temperature. Having said this, research had also stressed that temperature can have a significant impact on the rate of photosynthesis. Thus a firm conclusion can be made that photosynthesis compromises two processes known as the 'light dependant photochemical stage' & the 'light-independent temperature dependant stage'. From this we can see that light independent stages are primarily influenced by temperature.
In the chloroplast lamellae, light is trapped by pigments which can either be Chlorophyll's (a and b) or Carotenoids (B carotene and xanthophyll). Different pigments absorb different wavelength of light. An absorption spectrum for a particular pigment describes the wavelengths at which it can absorb light. The effectiveness of different wavelengths in promoting photosynthesis can be plotted an action spectrum:
Fig 1- Obtained from http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/AbsorptionSpectrum.gif
Pigments such as the ones listed above are arranged in a photosytem within the chloroplast lamellae. A photosystem is a light harvesting cluster of pigments, each which consist of a central primary pigment, which can be one of the two forms of chlorophyll a, with an absorption peak of 700 nm (P700) in photosystem 1 and 680 nm (P680) in photosystem 2. Surrounding accessory pigments can be either chlorophyll's a, b or carotenoids. These pigments trap light and pass the energy on to photosytem 1.
Fig 2 - www.sirinet.net/~jgjohnso /Ithylakoidmem.jpg
The process of reduction of carbon dioxide into carbohydrate is dependant upon a hydrogen carrier molecule nicotinamide adenine dinucleotide phosphate reduced (or NADP red), which provides the necessary hydrogen atoms for the reduction to take place. In the light dependant stages NADP becomes NADP red , which is then used in the light independent (temperature dependant stage) for the formation of a carbohydrate. The light independent stages involve cyclic phosphorylation and non-cyclic phosphorylation. As the name suggests, the first type of phosphorylation occurs in a cycle and other does not. During cyclic phosphorylation, a photon of light is trapped by photosystem 1, and an electron from the primary pigment (P700) is excited to a higher energy level. The electron is then trapped by an electron acceptor and passed via an electron chain. The energy released by the motion of the electron is used to synthesis ATP. Followed by cyclic phosphorylation comes non-cyclic phosphorylation, in which both of photosystems 1 and 2 are involved. Light is trapped by both photosystems and electrons emitted by both primary pigments (P700 and P600). The electrons are absorbed by electron acceptors and passed along a chain of electron acceptor in a 'Z- scheme'. In this the P700 in photosystem 1 absorbs electrons emitted by photosystems 2, and the P680 absorbs electrons emitted by the splitting of water during the process of photolysis. This is aided by an enzyme Ribulase bisphosphate carboxylase in photosytem 22. The resultant reactions are shown below:
2H2O ====> 4H+ + 4e- + 1O2
2
2NADP ====> 2NADP red
Two molecules on NADP red are formed (when NADP accepts two electrons from cyclic phosphorylation and a hydrogen ion) which are used in the light independent (temperature dependant) reactions to form triose phosphate. Oxygen is simply a waste product photolysis. The Z scheme is illustrated below:
Fig 3 - obtained from:
http://www.scool.co.uk/topic_quicklearn.asp?loc=ql&topic_id=15&quicklearn_id=2&subject_id=3&ebt=83&ebn=&ebs=&ebl=&elc=13
It is this light independent stage which is affected by the temperature because it involves an enzyme, Ribulose Bisphosphate Carboxylase (rubisco), which catalyses the reaction between carbon dioxide and a five-carbon sugar known as Ribulose Bisphosphate (RuBp). Enzymes are catalyst made of protein. They convert substrate molecules into products by possessing an active site where the reactions occur. The optimum temperature of rubisco is 45o C. Exceeding this temperature causes the bonds that hold the polypeptides in specific shapes to be broken and thus the active site changes shape3. The substrate (.i.e. Ribulose Bisphosphate) is unable to fit into the active site and therefore no photosynthesis occurs. The enzyme is said to be denatured. This is show below:
Fig 4 - obtained from http://www.biotopics.co.uk/other/aninac.html
Powered by the energy of sunlight, plants perform this central task of carbon fixation. Inside plant cells, rubisco forms the bridge between life and the lifeless, creating organic carbon from the inorganic carbon dioxide in the air. Rubisco takes carbon dioxide and attaches it to Ribulose Bisphosphate, a short sugar chain with five carbon atoms. Rubisco then clips the lengthened chain into two identical Glycerate -3-Phosphate pieces, each with three carbon atoms. Glycerate -3-phosphates are familiar molecules in the cell, and many pathways are available to use it. Most of the ...
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Fig 4 - obtained from http://www.biotopics.co.uk/other/aninac.html
Powered by the energy of sunlight, plants perform this central task of carbon fixation. Inside plant cells, rubisco forms the bridge between life and the lifeless, creating organic carbon from the inorganic carbon dioxide in the air. Rubisco takes carbon dioxide and attaches it to Ribulose Bisphosphate, a short sugar chain with five carbon atoms. Rubisco then clips the lengthened chain into two identical Glycerate -3-Phosphate pieces, each with three carbon atoms. Glycerate -3-phosphates are familiar molecules in the cell, and many pathways are available to use it. Most of the Glycerate -3-phosphate made by Rubisco is recycled to build more Ribulose bisphosphate, which is needed to feed the carbon-fixing cycle. But one out of every six molecules is skimmed off and used to make sucrose to feed the rest of the plant, or stored away in the form of starch for later use. In spite of its central role, rubisco is remarkably inefficient. As enzymes go, it is very slow. Typical enzymes can process a thousand molecules per second, but rubisco fixes only about three carbon dioxide molecules per second. Plant cells compensate for this slow rate by building lots of the enzyme. Chloroplasts are filled with rubisco, which comprises half of the protein. This makes rubisco the most plentiful single enzyme on the Earth.
Plants and algae build a large, complex form of rubisco composed of eight copies of a large protein chain and eight copies of a smaller chain. Many enzymes form similar symmetrical complexes. Often, the interactions between the different chains are used to regulate the activity of the enzyme in the process known as allostery. Rubisco, however, seems to be rigid as a rock, with each of the active sites acting independently of one another. In fact, photosynthetic bacteria build a smaller rubisco composed of only two chains, which performs its catalytic task just as well. By packing many chains together into a tight complex, the protein reduces the surface that must be wetted by the surrounding water. This allows more protein chains, and thus more active sites, to be packed into the same space.
The active site of rubisco is arranged around a magnesium ion. Above it is a small sugar molecule that is similar to the product of the rubisco reaction, and a short stretch of the protein chain is shown at the bottom. In reality, the rubisco protein chains completely surround these molecules. The magnesium ion is held tightly by three amino acids, including a surprising modified form of lysine. An extra carbon dioxide molecule is attached firmly to the end of the lysine side chain. In plant cells, this "activator" carbon dioxide, which is different from the carbon dioxide molecules that are fixed in the reaction, is attached to rubisco during the day, turning the enzyme "on," and removed at night, turning the enzyme "off." The exposed side of the magnesium ion is then free to bind to both ribulose bisphosphate, holding onto two oxygen atoms and the carbon dioxide molecule that will be attached to sugar 4.
Structure of rubisco:
Fig 4 -obtained from www.palaeos.com/Eukarya/Lists/EuGlossary/Images/Rubisco.gif
Blackman's law states that 'the rate of any process which is governed by two or more factors is limited by the factor in least supply'5. At low light intensities, increasing the temperature has little effect on the rate of photosynthesis, because the light intensity is a limiting factor. But at high light intensities, increasing the temperature (within limits) increases the rate of photosynthesis, by increasing the rate of light independent (temperature dependant) stages. At higher temperatures (above 45o C for RuBp) the proteins of the cell begin to denature and the rate falls. Below 0o C, the cells freeze and are destroyed by ice crystals. This explains why graphs cover a small temperature range. When light intensity is varied and all other factors remain constant, the rate of photosynthesis increases linearly with increased light intensity over a range of low intensities. The light intensity is said to be the limiting factor. At high light intensities, increasing the intensity has little effect on the rate of photosynthesis. A factor other than light intensity is limiting the rate of reactions ( e.g. the temperature). As with increasing the light intensity, increasing the concentration of carbon dioxide initially increases the rate of photosynthesis. Over this range of concentrations, the carbon dioxide is rate limiting. At higher concentrations, some other factor is rate limiting.
The graphs are shown below:
Fig 5 - Obtained from http://www.bbc.co.uk/schools/gcsebitesize/img/biphotorate.gif
Acknowledgements:
- Biology 2 (2001), by Mary Jones and Jennifer Gregory; page 26
2- http://www.sirinet.net/~jgjohnso/photosynthesis.html
3- Revise AS biology by Richard Fosbery and Jennifer Gregory; page 22
4- http://www.rcsb.org/pdb/molecules/pdb11_1.html
5- http://www.hydroponicsbc.com/co2.html
Prediction:
A fundamental of chemical thermodynamics is that all reaction rates will increase as the temperature increases. In the case of rubisco, increasing the temperature to the optimum rate (45o C) will inevitably increase the rate of which a water molecule is split during photolysis and hence there will be an increase in the volume of oxygen observed. This is because increasing the temperature increases the proportion of particles (i.e. substrates) that collide with energies greater than the activation energy (Ea) 6. Further more enzymes change the mechanism of a reaction to one having a lower value of activation energy (Ea), by providing an active site where reactions occur more easily than elsewhere7. Therefore, the proportion of successful collisions at a given temperature increases because they can be reached without a need of substantial energy and hence an increase in rate can be followed. This is had lead me to believe that the volume of oxygen will increase for each temperature up to the optimum temperature of rubisco, which is 45o C. At temperatures of 45o C, the enzyme is carrying out maximum catalysis as all its active sites are filled and in use. The enzyme is said to have reached its v- max8.
However, for reactions that are dependant on enzymes such as this one, means that if you were to go over the optimum temperature of the enzyme, although chemically you are increasing the chances of increasing the volume of oxygen, you are also increasing the chances of the breakdown of the three-dimensional structure of the enzyme. As the heat in the system increases, the vibrational energy of the entire rubisco molecule also increases. This puts a strain on the weak interactions that hold the enzyme together9. At temperatures just above optima, there may be a situation where the enzyme is in a sort of equilibrium where it temporarily loses some of its structure and then regains it to work again. At higher temperatures these bonds literally get shaken apart and the three -dimensional structure of the protein destabilises10. This has lead me to believe that if the temperature is to exceed 45o C, the enzyme will begin to denature and so the process of photolysis will decrease and eventually stop as would the volume of oxygen being produced.
Part of the experiment involves investigating the volume of oxygen produced when the elodea specimen is placed in ice. A leaf of a plant is an organ adapted for photosynthesis. The leaf structure varies greatly and is related to the environment in which the plant is in, e.g. the artic11. Therefore placing a plant in a freezing environment does not mean that it will not photosynthesise. This is evident in plants which are able to carry out photosynthesis in the artic. Subsequently Rubisco, the enzyme involved in photolysis of water can work in at freezing levels, though the rate of photosynthesis is extremely slow due to the very slow diffusion of enzyme and substrate molecules through the ice lattice. Therefore I can make a firm prediction that for this particular investigation, the volume of oxygen produced will be rather small as oppose to being zero.
Acknowledgements:
6-http://www.biologymad.com/master.html?http://www.biologymad.com/ASBiology.htm
7- Revise AS biology by Richard Fosbery and Jennifer Gregory; page 18
8- Biology 1 by Richard Fosbery and Mary Jones
9- Biology 1 by Richard Fosbery and Mary Jones
0- www.scool.co.uk/topic_quicklearn.asp?loc=ql&topic_id=12&quicklearn id=4&subject_id=3&ebt=79&ebn=&ebs=&ebl=&elc=13
1- Revise A2 biology by Richard Fosbery and Jennifer Gregory; page 20
Preliminary:
Apparatus:
* Boiling tube
* Kettle
* Elodea specimen
* Electric bench lamp with 100 W filament bulb
* Thermometer
* Ice
* Stopwatch
Procedure:
The investigation involves testing the elodea specimen in three conditions:
a). Ice
b). Water maintained at 45o C
c). Water at room temperature (tap water)
Proposed Method:
* Get hold of the elodea specimen and place it in the boiling tube.
* Put the boiling tube in a beaker surrounded by ice.
* Ensure the thermometer is standing upright in the beaker.
* Note the initial temperature and maintain this throughout the experiment, either by means of adding or reducing the ice content.
* Place the electric bench lamp towards the elodea specimen
* Allow the elodea specimen to settle for five minutes or so.
* On the fifth minute start timing for a further five minutes and count the amount of bubbles observed.
Note: The same procedure must be carried out for the other two experiments, only altering the content outside the boiling tube. In order to keep the water temperature at 45o C, it is advised that cool water or some heated water (from the kettle) is added depending on the temperature observed.
Prediction:
I predict that when the elodea specimen is placed in ice, a few (one or two) oxygen bubbles will be observed, therefore photosynthesis will be limited.
When the elodea specimen is placed in water at 45o C, more bubbles will be seen and hence the rate of photosynthesis will increase
At room temperature, some bubbles will be seen but much less compared to the 45o C investigation, since the temperature is in between.
Results:
Ice:
Time (minutes)
Number of bubbles observed
2
3
3
4
0
5
0
Total:
5
Water maintained at 45o C:
Time (minutes)
Number of bubbles observed
3
2
0
3
2
4
3
5
Total:
29
Water at room temperature (tap water):
Time (minutes)
Number of bubbles observed
0
2
2
3
3
4
3
5
3
Total:
1
Discussion:
From looking at my results, it appears to be that my prediction is reasonably accurate. As mentioned in my prediction, a few bubbles were observed when the elodea was placed in ice. This is because the cells within the elodea specimen eventually die. This can be explained by the concept of enzymes, which operate best at optimum temperatures. Placing the elodea in a cold environment, such as ice means that the temperature is extremely below the optimum. This inevitable leads to enzyme denaturation and only some bubbles are seen during the first two minutes prior to the denaturation. Consequently, there is some photosynthesis taking place.
When the elodea cell is placed in water which is maintained at 45o C, the number of bubbles sighted increase rapidly (particularly in the second and third minutes). Notice for the fourth and the fifth minutes, the number of bubbles observed start to decline. This may well be to the fact that the temperature was not controlled as intended, and possibly exceeded 45o C, thus causing the enzyme to denature. Hence a decrease in photosynthesis is observed.
When the elodea specimen is placed in water at room temperature, the number of bubbles observed are more or less the same. This is because the temperature of the water is fairly below the optimum, (which is believed to be 45o C) and therefore the rate of photosynthesis is limited.
Evaluation:
Despite the results fairly matching the prediction, the method used is rather unreliable. More repeats (i.e. three repeats) could have been put into practice as this would have allowed me to calculate an average and hence raising the reliability of the results. The temperature range is rather limited and so the results would have been more accurate by employing a variety of temperatures. This would have allowed me to pin-point exactly the optimum temperature of the enzyme, which is involved in photolysis.
Looking at the results above, there was an incidence where the temperature was not properly controlled (the ice investigation in which 3 bubbles were noted in the third minute). I believe using a water bath would have allowed me to maintain the temperatures more precisely and save time as oppose to using a kettle.
I recall whilst doing the experiment that the elodea specimen was placed somewhat close to the window. Light from the sun could have also played an important part of distorting the results because an increase in light intensity also contributes to an increase rate in photosynthesis. Therefore if this experiment is to be carried out again, it would be ideal to make use of the window blinds. Not forgetting to mention that the distance between the bench lamp and the elodea specimen was not fixed, and was varied during each investigation. This might have caused a slight degree of anomaly in the results. Having acknowledged this inconsistency has made me aware of what is required in the actual investigation.
It can be argued that counting the number of bubbles can be deceiving and therefore another method should be put into consideration. An alternative way of doing the same experiment more accurately can be achieved by using a photosynthometer. A freshly cut strand of the plant is suspended upside down in a boiling tube. The healthy strand of elodea produces bubbles of oxygen gas when brightly illuminated (i.e. with a bench lamp 10 cm away from the elodea specimen) at different temperatures. The bubbles emerge from the cut end of the stem and are collected in a bulb at the base of the apparatus. From here, the oxygen gas can be drawn into the capillary tube by means of the syringe. The volume of oxygen gas collected in five minutes gives a direct measurement of the rate photosynthesis.
Apparatus and Justification:
Apparatus
Justification of Apparatus
x1 Clamp stand (with capillary tube)
* A lot of apparatus are involved, some of which that need to be held at a constant height above the water bath (i.e. the boiling tube with the elodea specimen).
x1 Capillary tube with ruler.
* Used to measure the length of the oxygen bubble(s).
* Hence the volume of oxygen can be calculated.
x1 Boiling tube
* The use of a boiling tube is necessary as oppose to a test tube because it's large enough to allow the elodea specimen to fit in with ease.
x1 Elodea Canadensis specimen (10 cm long)
* The elodea specimen is the basis for this investigation.
* Allows the hypothesis to be tested.
x1 5 ml syringe
* A 5 ml syringe is necessary to allow oxygen bubbles to be drawn in the capillary tube. No other apparatus can be substituted for this task.
x1 30 cm Ruler
* Used to measure the length of the elodea specimen, making sure that the length is constant for each investigation.
* To ensure a fair test.
x1 Scalpel
* Used to cut the elodea specimen to the desired length with precision.
x1 Plastic Tile
* To aid in cutting the elodea specimen.
* To prevent any damage to the work bench.
x1 Electric bench lamp with 100W filament bulb
* Used to ensure a fair test as every investigation will be illuminated by a lamp at a set distance.
* To ensure the results are not influenced by light intensity but solely the temperature.
x1 Thermometer
* Used to ensure the temperature of water bath is correct, and hence to promote reliability of results.
x1 Stopwatch
* Used for timing the investigation for 10 minutes (five minutes for the settling of the elodea specimen and another five minutes for the investigation).
x1 Beaker and ice blocks
* To be used for the 0o C investigation.
* To see if there is any photosynthesis evident at freezing level.
Proposed Method:
Diagram12:
. Set up the clamp stand as shown above.
2. Get hold of a plastic tile and a scalpel and cut the elodea specimen at a length of 10 cm.
3. The cut end has to be inserted into the calibrated capillary tube as shown above.
4. Lower the capillary tube into the water bath, ensuring half of the boiling tube (containing the elodea specimen) is immersed in the water.
5. Place the bench lamp 10 cm away from the boiling tube. Ensure the light is directly facing the elodea specimen.
6. After setting all the apparatus up, pull the syringe on top of the capillary tube in order for the water to get into the capillary tube. This removes any air bubbles initially present in the capillary tube.
7. Place the thermometer into the water bath (or beaker in the case of the ice investigation) and turn the light on. The elodea must be allowed to settle for five minutes.
8. Time the investigation for a further five minutes by using a stopwatch.
9. On completion of the five minutes, switch the lamp off and remove the clamp stand along with the rest of the apparatus out of the water bath.
0. Pull the syringe to draw the oxygen bubbles into the capillary tube and measure the length of the bubble(s) simultaneously by making use of the ruler.
1. Note down the length of the bubble(s) on paper.
2. Repeat the same procedure three times for each temperature using the same elodea specimen.
3. Once the three trials are complete, move on to the next temperature. and carry out steps 1 -13
Ice investigation:
* Get hold of the elodea specimen and place it in the boiling tube.
* Put the boiling tube in a beaker surrounded by ice.
* Note the initial temperature and maintain this throughout the experiment, either by means of adding or reducing the ice content.
* Follow steps 5-13 above.
Note: If an anomalous result is encounter during the duration of the experiment, it is advised to do that particular investigation again.
Acknowledgements:
2- Diagram modified from A-Level biology Revised Edition by W D Phillips and
T J Chilton, page 69.
Analysis of Variables:
Independent variable: The independent variable is the variable, which has to be manipulated in order to get the desired results. In this case, the independent variable is the temperature of the water baths. To obtain more accurate results, I have included temperature readings ranging from 0-65o C, in intervals of five. Three readings will be taken for each temperature and compared.
Dependent variable: This is the variable which responds to the fixed conditions and which is used to test the hypothesis. In this case, the dependent variable is the volume of oxygen released by the elodea specimen. The length of the oxygen bubble(s) is going to be measured at the end of the five minute interval. This can be used to deduct the volume of oxygen produced by multiplying the length of the bubble(s) by pie, which is then multiplied by 0.82
Fixed variables: These are variables, which have to be kept constant throughout the experiment in order to obtain accurate results. These variables cannot be manipulated at any time of the experiment. Some of the fixed variables are listed below:
* The light intensity (distance between the bench lamp and the elodea specimen):
This can be kept constant by ensuring the elodea specimen is 10 cm away from the bench lamp. It may well be convenient reassure the distance with a ruler. The preliminary work I did have done has highlighted that 10 cm happens to be an ideal distance for sufficient photosynthesis to be followed and thus reliable results can be obtained. However if the distance between the bench lamp and elodea specimen is shorter than 10 cm, then this will have a major impact on the results. The increase in light intensity shall inevitably results in an increase in the volume of oxygen noted and thus distorting the results. Similarly if the distance is greater than 10 cm, then this decrease in light intensity shall contribute to a decrease in rate of photosynthesis and thence slowing down the rate at which the oxygen bubble(s) are released13. Therefore it is vital that this distance is kept constant throughout the experiment to ensure a fair test.
* The number of leaves on the Elodea plant:
The number of leaves will be kept constant throughout the whole experiment by using the same elodea specimen. The reason for keeping the same number of leaves is to ensure that the surface area provided by the leaves is the same in each investigation. Having the same number of leaves will provide the same surface area. If the number of leaves were different in each new investigation, then the number of leaves would be the independent variable. The more leaves there are the larger the surface area, and more light energy will be trapped by the leaves and a greater proportion of it will be converted into chemical energy14. Therefore more oxygen will be given off. On the other hand, a fewer amount of leaves shall results in a low yield of oxygen. In both cases, the results will be distorted if not controlled.
Acknowledgements:
3- Letts Revise A2 Biology by John Parker, page 26
4- Revise A2 biology by Richard Fosbery and Jennifer Gregory; page 21
Reliability:
> To obtain more reliable results, three measurements would be taken in the same condition. The reason for this is that if in case, an error was made on the first attempt, the error can be amended and on the second attempt. After doing the experiment, if any of the results are anomalous then the experiment should be repeated. Results obtained can be compared to the previous results to see if there is an agreement.
> Light from the sun can also play an important part of distorting the results because an increase in light intensity also contributes to an increase rate in photosynthesis. Therefore it would be ideal to make use of the window blinds to promote reliability of results.
> Temperatures are monitored precisely by the water baths. However it is sometimes observed that the temperature of the water bath goes up or down by a degree or two. The temperature can be maintained by means of adding or removing ice to the water baths.
> Due to the limited number of water baths, there may well be the case of sharing a water bath to five others. This means five additional bench lamps would have an impact on my results (as light intensity increases rate of photosynthesis). The lamps may also contribute to the water baths getting hotter than required. Therefore it would be wise to carry out the investigation individually.
> When the apparatus are set up, the syringe (on top of the capillary tube) must be pulled to draw the water into the capillary tube. This will remove any air bubbles initially present in the capillary tube and thus leaving no ambiguity.
Results:
Table: showing the results I obtained during the investigation
Temperature
(o C)
Length of Oxygen bubble
(mm)
Volume of Oxygen
(mm)
Rate of photosynthesis
(mm3/min)
Average rate of photosynthesis
(mm3/min)
0.00
.00
2.01
0.40
0.67
0.00
2.00
4.02
0.80
0.00
2.00
4.02
0.80
0.00
4.00
8.04
.60
.87
0.00
6.00
2.06
2.41
0.00
4.00
8.04
.60
5.00
8.00
6.08
3.22
2.68
5.00
6.00
2.06
2.41
5.00
6.00
2.06
2.41
20.00
8.50
7.09
3.42
3.02
20.00
8.00
6.08
3.22
20.00
6.00
2.06
2.41
25.00
9.00
8.09
3.62
3.49
25.00
9.00
8.09
3.62
25.00
8.00
6.08
3.22
30.00
8.00
6.04
3.21
4.02
30.00
0.00
20.11
4.02
30.00
2.00
24.13
4.83
35.00
2.00
24.13
4.83
5.23
35.00
4.00
28.14
5.63
35.00
3.00
26.13
5.23
40.00
4.50
4.50
.81
.81
40.00
5.00
5.00
2.01
40.00
4.00
4.00
.61
45.00
3.00
6.03
.21
.41
45.00
4.00
8.04
.61
45.00
3.50
7.04
.41
50.00
2.00
4.02
0.80
0.87
50.00
2.50
5.03
.01
50.00
2.00
4.02
0.80
55.00
3.00
6.03
.21
.07
55.00
3.00
6.03
.21
55.00
2.00
4.02
0.80
60.00
0.50
.01
0.20
0.33
60.00
.00
2.01
0.40
60.00
.00
2.01
0.40
65.00
.00
2.01
0.40
0.27
65.00
.00
2.01
0.40
65.00
0.00
0.00
0.00
Table: Showing the results obtained from the class