Factors Affecting The Rate Of Photosynthesis Biology Essay

The intent of this experiment is to detect the factors impacting the Photosynthetic rate of foliages, which is measured in two ways. First altering the light strength, this will find the rate of addition or lessening in photosynthesis. Second altering the handiness of foods ( Concentration of CO2 ) to the workss, this will straight impact the photosynthetic rate. To prove the light strength, an Elodea submerged in a beaker was placed at different measuring off from the works, to see if O ( bubbles ) is produced.

To prove the handiness of foods, different molar concentrations of Sodium Bicarbonate was diluted in 500 milliliter of H2O with Elodea, to see if rate of photosynthesis increased or decreased.

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The consequence shows, as light strength additions, the rate of reaction will increase at a relative rate until a certain degree is reached. At a light strength of 400 the mean addition in rate of reaction was 746v. At 4 the mean addition in rate of reaction was 8676v, a difference of 7930v, which shows the rate of reaction is greatly influenced by light strength.

As the molar concentration of Sodium Bicarbonate additions, the rate of reaction will besides increase at a relative rate with regard to light strength. At 0.05M the mean addition in rate of reaction was 0.80r. At 0.1M the mean addition in rate of reaction was 1.90r, a difference of 1.1r, which shows the rate of reaction is besides significantly influenced by the handiness of foods.

Both light strength and handiness of foods are of import factors that affect the rate of photosynthesis.

Purpose

To look into how different factors affect the rate of photosynthesis. The variables that will be changed are different strength of light and different molar concentrations of Sodium hydrogen carbonate and so mensurating the rate of reaction ( photosynthetic rate ) .

Hypothesis

Throughout this experiment the light strength and different molar concentrations of Sodium Bicarbonate will be varied. The variable that is measured will be clip, for rate of reaction.

As light strength increases the rate of reaction will increase at a relative rate. As the concentration of NaHCO3 increases the rate of the reaction will besides increase at a relative rate.

Introduction

Every species on Earth needs some sort of energy beginning in order to last. In carnal cells, the chondriosome produce ATP from cellular respiration. However, the works cells have a different type of centre that produces energy-chloroplasts. Plants go through the procedure of photosynthesis. The chief procedure of photosynthesis is the soaking up of visible radiation by chlorophyll, found in foliages and the submergence of C dioxide from the environment, and together they produce O and sugar ( energy ) . The equation below represents the photosynthesis reaction:

The intent of this experiment is to prove whether factors such as light strength and degree of Carbon dioxide, will impact the rate of photosynthesis, which are the two most of import variables in the photosynthesis procedure. This was demonstrated by Robert Hill in 1938, known as “ The Hill Reaction ” . Robert Hill and his associates at the University of Illinois found that the photosynthetic rate varies with light strength, and as the light strength additions, the reaction rate besides increases up to a certain point.

Apparatus needed for the Experiment

Pondweed

20mmA? syringe

Capillary tube

Base

Stopwatch

Ruler

NaHCOA? Solution

Bench lamp

Distilled H2O

Figure A ) Potometer

Method

The setup is set ( see Fig. A ) with the syringe full of the 0.01M solution of NaHCO3 solution. Two Markss 10cm apart are made on the capillary tube.

The syringe is placed 0.05m off from the lamp.

Using the syringe plunger the semilunar cartilage of the NaHCO3 is set so that it is flat with the first grade.

A stop watch is so started. The semilunar cartilage should bit by bit travel down the capillary tubing as the Elodea produces oxygen as a byproduct of photosynthesis. As the O is produced it increases the force per unit area in the syringe and so the semilunar cartilage is pushed down the tubing.

Light Intensity = 1 / DistanceA? ( m )

When the semilunar cartilage reaches the degree of the bottom grade the stop watch should be stopped.

Light strengths have been worked out utilizing the undermentioned equation:

6. Using the same piece of Elodea and the same distance between the lamp and the syringe the experiment ( stairss 1 to 5 ) should be repeated for the other concentration of NaHCO3.

7. The experiment ( stairss 1 to 6 ) should so be repeated at each different distance between the syringe and the visible radiation for all the NaHCO3 concentrations. The staying distances are 0.05m, 0.06m, 0.07m, 0.08m, 0.1m, 0.2m, 0.3m, and 0.5m.

8. The full experiment should so be repeated three times in order to obtain more accurate informations and to acquire rid of any anomalousnesss that may happen in a individual experiment.

In order to do this experiment every bit accurate as possible a figure of stairss must be taken.

The same piece of Elodea should be used each clip in order to do certain that each experiment is being carried out with the same foliage surface country.

The sum of NaHCO3 solution should be the same for each experiment. 20mmA? should be used each clip.

The distance should be measured from the forepart of the lamp to the syringe. Although taking these stairss will do the experiment more accurate, its truth is still limited by several factors.

From these recorded times I will work out the rate of the reaction utilizing the undermentioned equation.

Rate of the Reaction = 1 / Time ( s )

Consequences

Table1. ( Average of the 4 trails of Molarity against Light strength ) :

Molarity of NaHCO3

Light Intensity 1/dA? ( m )

0.00

( Distilled H2O )

0.01

0.02

0.05

0.07

400

3571

1666

1099

523

200

278

1670

5183

988

600

375

204

4998

4485

1175

1005

473

156

5590

2300

1770

1445

621

100

9990

3150

2900

2552

1224

25

A

4762

3984

2850

1640

11

A

5945

4348

3780

2830

4

A

16480

11904

5196

6578

Using these consequences I worked out the rate

Rate Of the Reaction = 1 / Time ( s ) ten 1000

The rate was multiplied by 1000 to do the Numberss easier to manage.

Table2.Average of the 4 trails in rate of reaction:

Molarity of NaHCO3

Light Intensity 1/dA? ( m )

0.00

( Distilled H2O )

0.01

0.02

0.05

0.07

400

0.28

0.60

0.91

1.91

5.00

278

0.60

0.19

1.01

1.67

2.67

204

0.20

0.22

0.85

1.00

2.11

156

0.18

0.43

0.56

0.69

1.61

100

0.10

0.32

0.34

0.39

0.82

25

A

0.21

0.25

0.35

0.61

11

A

0.17

0.23

0.26

0.35

4

A

0.06

0.08

0.19

0.15

Light strength against NaHCO3

Graph1.

Analysis & A ; Discussion of Results

Analysis:

Distilled H2O: With the distilled H2O the rate of reaction went up from 0.1 to 0.4 when the light strength was increased from 100 to 400. This is a 4 times rise which is rather big. The curve on the graph does nevertheless level out rather shortly demoing that the rate is being limited by the deficiency of NaHCO3 in the H2O.

0.01M NaHCO3: At a light strength of 4 the rate is 0.06 but this rises to 0.6 when the light strength is brought up to 400. The curve is really shallow and degrees off towards a light strength of 350 – 400.

0.02M NaHCO3: The sum of NaHCO3 is dual that of the 0.01M NaHCO3 experiment. The rate besides finishes off twice that of the 0.01M experiment. This would propose that there was a straight relative relationship between the sum of NaHCO3 and the rate of reaction.

0.05M NaHCO3: The curve for the 0.05M NaHCO3 is steeper than the old curves. The rate rises to 1.9 at a light strength of 400.

0.07M NaHCO3: The 0.07M NaHCO3 trial produces a line which is steeper than all the old curves. The works is utilizing the excess CO2 to photosynthesize more. As the works has more CO2 the modification factor caused by the deficiency of CO2 is reduced. This trial did bring forth a large anomalousness. The rate for a light strength of 400 is 5. By following the line of best tantrum I can see that this consequence should be more like 3.5. The Elodea for this trial was really near to the light beginning. It is possible that it had been left here for a piece which caused the lamp to heat the Elodea up. This would hold increased the rate of reaction of the works ‘s enzymes which would hold increased the photosynthesis rate.

0.1M NaHCO3: The 0.1M NaHCO3 produced the steepest line. Near the terminal of the line it looks as if the rate of reaction is hit by another restricting factor. The line goes up steadily but so between a light strength of 300 and 400 degrees off really rapidly. This would propose that at a 0.1M NaHCO3 is sufficient for the works to photosynthesize at its maximal rate with its current environmental conditions. Increasing the NaHCO3 concentration after this degree would hence hold no consequence unless the following modification factor was removed.

Discussion:

The hypothesis was that the rate of photosynthesis would increase if the light strength and NaHCO3 degrees were increased ( delight refer to Graph1 ) . As the Elodea absorbed the visible radiation and CO2 it produced O gas which increased the force per unit area in the syringe. This pushed the air bubble in the capillary tubing down. The chloroplasts produce ATP and cut down NADP to NADPH2 when exposed to visible radiation. It is at this phase of the reaction that O is produced as a waste merchandise, moreover, the informations collected was supported by the consequences obtained by Robert Hill and his associates at the University of Illinois, where they predicted, as the light strength and NaHCO3 degrees increased, the rate of photosynthesis will besides increase up to a certain degree ( delight refer to Graph2 )

As predicted when the light strength additions so does the rate of photosynthesis. It was predicted that a degree would be reached where increasing the light strength would hold no more consequence on the rate of reaction as there would be some other restricting factor which limits the rate of the reaction. The rate additions at a steady rate as the light strength additions until near the terminal of each line where the rate decreases. This is either because the photosynthesis reaction has reached it ‘s maximal rate of reaction or another factor is restricting the rate. As 6 different CO2 concentrations were used I can see that the first five reactions are non happening at their maximal rate as there is the 0.1M NaHCO3 remainder which is happening at a faster rate so the other 5. The photosynthesis reactions of the other five trials must hence be limited by the concentration of CO2 to the works.

As predicted when the NaHCO3 concentration is increased the works in able to acquire more CO2 which causes the rate of reaction to travel up. It was predicted that one time the NaHCO3 had been raised above a certain degree increasing the rate farther would hold no consequence as there would be other restricting factors restricting the rate of the reaction. As the NaHCO3 concentration the H2O was increased the rate of photosynthesis besides increased. The works therefore made more O as a waste merchandise. At a NaHCO3 concentration of 0.1M once the light strength gets above 300 the rate of reaction lessenings significantly. This could be because photosynthesis is happening at it ‘s maximal possible rate or because another modification factor is keeping the rate of reaction.

The fact that the curve degrees off so rapidly indicates that there is another restricting factor keeping photosynthesis. It could be temperature. These trials are being carried out at room temperature so the temperature would hold to be raised another 15°C before the enzymes in the works ‘s cells were at their optimal on the job temperature. More trials could be done by utilizing H2O that was at a higher temperature to see what consequence this would hold on the photosynthesis rate. It is nevertheless impossible to raise the works ‘s temperature without affect other factors. For case the existent sum of O released by the works is somewhat more than the readings would propose as some of the O would fade out into the H2O. At a higher temperature less O would be able to fade out into the H2O so the readings for the photosynthesis rate could be unnaturally increased.

It is besides possible that the photosynthetic reactions in the works are happening at their maximal possible rate and so can non be increased any more. The visible radiation is likely non a confining factor as all but one of the curves level off before the maximal light strength of 400 is reached. The maximal light strength that the workss can manage is hence merely below 400.Water will non be a confining factor as the workss are populating in H2O. They hence have no pore and absorb all their Carbon dioxide by diffusion through the foliages.

Graph1. Light strength against NaHCO3 – MY Consequence

Graph2. Light strength against NaHCO3 – Beginning

Restrictions and Improvement

The truth of this experiment is limited by a figure of factors.

Some of the O give off is used for respiration by the works.

Some of the O dissolved into the H2O.

Some was used by little invertebrates that were found life within the pieces of Elodea.

The higher light strengths should be rather accurate but the smaller light strengths would be less accurate because the light spreads out. The Elodea will besides acquire background visible radiation from other experiments.

The visible radiations are besides a beginning of heat which will impact the experiments with merely a little distance between the visible radiation and the syringe. This warming could impact the consequences.

Using the same piece of Elodea for each experiment was impractical as the Elodea ‘s photosynthesis rate decreased over clip. By utilizing a different piece of Elodea for each experiment did make the job of it being impossible for each piece to hold the same surface country.

This experiment could be improved in a figure of ways.

It could be repeated more times to assist acquire rid of any anomalousnesss. A better overall consequence would be obtained by reiterating the experiment more times because any mistakes in one experiment should be compensated for by the other experiments.

Each individual should hold done their experiments in a different room to cut out all background visible radiation.

All the experiments should be done consecutive.

A Lucite screen could hold been placed between the visible radiation and the syringe to cut down any warming consequence that the visible radiation may hold.

The experiment could hold been carried out with higher NaHCO3 to see if increasing the concentration would increase the rate of photosynthesis, or if a concentration of 0.1M NaHCO3 produces the maximal rate of photosynthetic reaction.

Decision

The purpose of this experiment was to look into different factors that affect the rate of photosynthesis. The hypothesis was, as light strength increases the rate of reaction will increase at a relative rate. As the concentration of NaHCO3 increases the rate of the reaction will besides increase at a relative rate. This was right, supported by the informations collected which shows at a light strength of 400 the mean addition in rate of reaction was 746v. At 4 the mean addition in rate of reaction was 8676v, a difference of 7930v, which shows the rate of reaction is greatly influenced by light strength. This was demonstrated by Robert Hill and his associates, with similar consequences to this experiment, which they found that the photosynthetic rate varies with light strength, and as the light strength additions, the reaction rate besides increases up to a certain point.

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