Name: Dominic SinghDate: 9/12/14Form: U6-4Subject: BiologyLab #: 2Teacher: Ms. Serjeant

Title: RespirationAim: To determine the rate of respiration between germinated and non-germinated seeds and beads at 25oC and 10oC.Introduction:Respiration can be defined as the biochemical process that involves the breakdown of complex organic compounds such as carbohydrates into simpler molecules. The energy released is used to make adenosine triphosphate (ATP) which us the molecular currency of energy and it transports chemical energy in cells for metabolism.The two ways respiration can occur in organisms are aerobically and anaerobically. Aerobic respiration requires the presence of oxygen while anaerobic respiration can take place without the presence of oxygen. Aerobic respiration has four main steps which are glycolysis, the link reaction, Krebs cycle and electron transport chain and each of these steps are controlled by enzymes. For each glucose molecule that has passed through these four steps there is a net gain of 36 ATP in aerobic respiration.Since enzymes have a major role in respiration temperature has a large impact on the rate of enzyme activity and therefore there will be a large impact on rate of respiration. Other factors such as enzyme concentration, substrate concentration and presence of enzymes inhibitors also have an impact on enzyme activity. All enzymes have an optimum temperature in which they function at and if the temperature goes too high or too low there will be a decrease in enzyme activity. At lower temperatures enzymes have less kinetic energy and move slowly therefore enzyme substrate complexes are formed slowly and enzyme activity decreases. At higher temperatures than an enzymes optimum temperature enzymes become denatured due to the very high amounts of kinetic energy the enzyme possess and this also lowers enzyme activity. Therefore the rate of respiration will decrease at very low or very high temperatures.A respirometer is a piece of apparatus used to measure the rate of respiration. It measures the oxygen uptake by aerobically respiring organisms. Carbon dioxide is removed from the air inside the apparatus with a carbon dioxide absorbent such as potassium hydroxide and therefore the drop in the volume of air in the apparatus results directly from the use of oxygen by the organisms. Therefore if readings are taken at time intervals the rate of respiration can therefore be calculated.Apparatus/ Materials: water bath, 6 vials, 100ml graduated cylinder, germinating seeds, distilled water, paper towel, non-germinating seeds, glass beads, absorbent cotton ball, potassium hydroxide, pipette, non-absorbent cotton ball, stoppers, washers, masking tapeMethod: 1. A water bath was setup and chilled to 10oC.2. 6 vials with steel washers on the bottom were numbered 1 to 6 with a glass marking pen.3. 100ml graduated cylinder was filled with 50ml of water. Ten germinated seeds were added and a reading of displaced water was taken. This was the volume of germinated seeds and it was noted. The seeds were removed and placed on a paper towel which was set aside.4. The graduated cylinder was refilled with 50ml of water. Ten dry non-germinated seeds were added and glass beads were added until the water level was the same as with the germinated seeds. The seeds and beads were removed and placed on a paper towel which was set aside.5. The graduated cylinder was refilled with 50ml of water. Glass beads were added until the water level was the same as with the germinated seeds. The beads were removed and placed on a paper towel which was set aside.6. Steps 3 through 5 were repeated with more germinated seeds, non-germinated seeds and glass beads and glass beads only. Everything was then set aside.7. An absorbent cotton ball was placed in each of the six vials and 1ml of KOH was added to the cotton with a pipette. A non-absorbent cotton ball was placed on top of the KOH soaked absorbent cotton.8. The first set of germinating seeds, dry non-germinating seeds and glass beads and glass beads only were placed in vials 1 through 3 respectively. The second set of germinating seeds, dry non-germinating seeds and glass beads and glass beads only were placed in vials 4 through 6 respectively. A stopper assemble was firmly inserted into each of the six vials. A second washer was placed 9. A piece of masking tape was stretched across the upper edge of the water bath to keep the pipettes out of the water as the vials are equilibrating.10. Vials 1 through 3 were placed in the room temperature water bath (25oC). Vials 4 through 6 were placed in the chilled water bath (10oC). The pipettes were rested on the masking tape while the vials equilibrated for 10mins. 11. The masking tape was removed and all six respirometers were fully immersed in the water bath. The respirometers were arranged so that the pipette gave a clear reading. The respirometers were not touched after the experiment had started. The respirometers were allowed to equilibrate for 5 minutes.12. The pipette readings were then taken at 5 minute intervals and all results were recorded in Table 1.

Results:TABLE 1 SHOWING THE CORRECTED DIFFERENCE FOR GERMINATING PEAS AND DRY PEAS AND BEADS FOR 25oC AND 10oC AT 5 MINUTE INTERVALS. Temp.(oC)Time(mins.)Germinating PeasDry Peas and BeadsBeads Only

Reading (ml)Diff. (ml)Corr. Diff. (ml)Reading (ml)Diff. (ml)Corr. Diff. (ml)Reading (ml)Diff. (ml)

250(initial)8.800.000.009.000.000.009.000.00

2558.400.400.409.000.000.009.000.00

25107.801.001.009.000.000.009.000.00

25157.451.351.258.950.05-0.058.900.10

25207.001.801.708.950.05-0.058.900.10

25256.602.202.108.900.100.008.900.10

25305.803.002.908.900.100.008.900.10

100(initial)8.250.000.008.500.000.008.500.00

1058.35-0.10-0.158.500.00-0.058.450.05

10108.100.150.058.450.05-0.058.400.10

10158.050.200.108.450.05-0.058.400.10

10207.950.300.208.400.100.008.400.10

10257.750.500.408.400.100.008.400.10

10307.600.650.508.400.10-0.058.350.15

Sample Calculations:DifferenceDifference = Initial reading at 0 reading at time xDifference at 5 minutes for 25oC is = 8.80-8.40 = 0.40Corrected DifferenceCorrected difference = (initial seed readings at 0 seed readings at time x) (beads at time 0 beads at time x)Corrected difference at 5 minutes for 25oC = (8.80 - 8.40) (9 9) = 0.40Rate of RespirationRate of respiration was determined by calculating the gradient of each line on the graph.

Gradient = Points- (6,0.52), (27.5, 2.36)

Rate of respiration for germinating seeds at 25C = = 0.0856 ml/ min

Discussion:Plants respire throughout the day and night, taking in oxygen and producing carbon dioxide. Photosynthesis also occurs in plants and that causes plants to take in carbon dioxide and produce oxygen. Therefore in order to measure the rate of respiration germinating seeds were use since photosynthesis does not occur in them and therefore the seeds would not produce oxygen which would cause inaccurate results. Also potassium hydroxide was placed in cotton balls inside the vials so it would absorb any carbon dioxide produced by the seeds and therefore the pipette reading would show the amount of oxygen consumed by the germinating seeds.When the germinating seeds take in oxygen the pressure inside of the vial decreases and this therefore forces water into the pipette. This setup is called a respirometer and the reading on the pipette was taken to show how much oxygen is consumed at five minute intervals.Glass beads were used in this lab as a control in which readings could be compared too. The help account for fluctuations in temperature during the lab. There was a small decrease in the amount of oxygen in the respirometers during the lab due to fluctuations in the temperature of the water in which the respirometers were submerged. Also of the vials were left to equilibrate for five minutes in order for the temperature of the seeds and that of the water bath to be equal and to allow any carbon dioxide trapped inside of the respirometers to be absorbed by the potassium hydroxide leaving only oxygen and causing no inaccuracies in the results.The germinating seed at 25C had the highest rate of respiration which was 0.0856ml/min. This occurred because these seeds were respiring and was placed in the 25C water bath. Since respiration has many enzymes taking place in each reaction the temperature of 25C was the optimum temperature for the enzymes to function. This allowed enzyme to have sufficient kinetic energy to quickly form enzyme substrate complexes and allows a high rate of reaction. This high rate of reaction then directly influences the rate of respiration increasing it. The germinating seed at 10C had a much lower rate of respiration which was 0.0123ml/min. This occurred because these seeds were respiring and was placed in the 10C water bath. Since respiration has many enzymes taking place in each reaction the temperature of 10C was much lower than the optimum temperature for the enzymes to function. This caused enzyme to not have sufficient kinetic energy to quickly form enzyme substrate complexes and therefore causing it to have a very slow rate of reaction. This low rate of reaction then directly influences the rate of respiration decreasing it. The dry seeds and glass beads at 25C and at 10C rate of respiration was 0.00ml/min. This is due to the seeds not respiring and therefore the temperature change would not have had an effect on these results.Some precautions are to ensure that the respirometer was closed tightly forming a vacuum and to ensure that apparatus was not contaminated. A source of error for this experiment was parallax error when taking readings and a limitation of this experiment was that the respirometer does not account for changes in gas volume due to temperature changes which could have caused inaccurate results. Also this experiment could have been improved by adding food colouring to the water so the values would be easier to read. Conclusion:In conclusion it was determined that the rate of respiration for the germinating seed at 25C was 0.0856ml/min, for the germinating seeds at 10C the rate of respiration was 0.0123ml/min and for the dry seeds and beads at 25C and at 10C the rate of respiration was 0.00ml/min.