Shorter wavelengths of energy have greater amounts of energy. What was the purpose of the vacuum on the syringe? When the air spaces are infiltrated with a solution of water, the overall density of the leaf disk increases and the disk sinks. Green light will be reflected off because the plant itself is green. What is the environmental affect of the rate of photosynthesis? Ivy or fresh spinach and are also required. So, sodium bicarbonate was not able to enter the spaces in the leaf disks that would have caused more of them to rise. Discussion and Conclusion: According to the data, none of the leaf disks placed in the beaker with only water, floated to the top. A potential error could have been that the vacuum was not created properly.
Analyzing Data To make comparisons between experiments, a standard point of reference is needed. How will air return to these spaces? Suspend the syringe until all leaf disks are sunk 13. Plants take inorganic compounds carbon dioxide and water and convert them to G3P, an organic compound. Both the experimental group and the control should run until all the discs are floating. What will happen if you remove the air from these spaces? Inquisitive minds can come up with many additional projects.
Examine the factors that affect photosynthesis in land plants by using the most practical method for a school laboratory—the floating leaf disk technique. Ivy seems to provide very consistent results. Explain why you would expect these results. Hold the syringe vertically, with the tip pointed upwards, and push in the plunger to expel the trapped air. Light speeds up the rate, but not as far as the denaturing of the chloroplasts 3. This is a particular problem if your laboratory instruction emphasizes student-generated questions.
My classes have found that in the spring, Pokeweed may be the best choice. Photons of light are captured and the energy is transferred to molecules in the plant cells. Make a solution of sodium bicarbonate by mixing 300 ml of water to a a pinch of baking soda about 100 ml to 1g 3. Once the students are familiar with the technique they can readily design experiments to answer their own questions about photosynthesis. The equipment and supplies needed are inexpensive, simple, and readily available.
Some leaf surfaces are more water repellent than others are. Set up the lamp next to the beaker and adjust the distance to 15 cm. Background and PreLab Photosynthesis fuels ecosystems and replenishes the Earth's atmosphere with oxygen. Use of their high number of chloroplasts per cell 7. Adding a bit more soap usually solves the problem. Oxygen and carbon dioxide are exchanged through openings in the leaf called stoma.
If your solution generates suds then dilute it with more bicarbonate solution. Is the rate of photosynthesis constant in Fast Plants® or does it vary according to the stage of the life cycle? Choose from the list of variables below to investigate. How does temperature affect the rate of photosynthesis? Add one drop of this dilute soap solution to your 300 ml bicarbonate solution. The number of disks that float per unit of time gives a measure of the rate of photosynthesis. Experimental Question: What factors affect the rate of photosynthesis? Air spaces causes the leaf disks to float. You can use the syringe as the reaction chamber, but there are advantages to transferring the disks from the syringe to the beaker. It is added to facilitate photosynthesis.
Wavelengths of light within the visible part of the light spectrum power photosynthesis. When visible light is absorbed by leaf pigments, such as chlorophyll a or b, during the light reactions of photosynthesis, electrons within each photosystem are boosted to a higher energy level and replaced by the splitting of H 2O molecules. Would this also reduce the rate of photosynthesis as compared to the? Then swirl the disks to dislodge any that are stuck against the sides of the cups. Plants can then either break down the glucose immediately to release the captured energy in a process called respiration, or can store the glucose molecules as starch and cellulose for later use. Control Group: Repeat your set-up from above, but this time do not place baking soda in the beaker. What is the solution for coagulation occurring in the boiled chloroplasts? When you release the plunger, liquid infiltrates the tissue.
Continue until all of the disks are floating. If the experiment did not go as expected, offer an explanation. If no disks float within 5 minutes, add a couple more drops form your soap solution and start the time over again. As you punch out the leaf disks, put them into the syringe. Obtain two separate cups labeled heated water solution and bicarbonate solution.
Tap the side of the syringe so that the disks are at the bottom, and then reinsert the plunger—being careful not to crush the leaf disks. By the end of the ten minutes, five leaf disks had floated to the top. Swirl gently to avoid making suds. Procedure Remove the plunger from a syringe. Sodium bicarbonate Baking soda 2. Place you beaker as close to the light as possible. For example, high-energy ultraviolet rays, with wavelengths of approximately 1 nanometer nm to 380 nm, can harm living tissues due to the large amount of energy they carry.