Test tube 4 had very sporadic readings Table I. Leaf Structure and Function In this investigation, you will use a system that measures the accumulation of oxygen in the leaf. Plant material will generally float in water. Hypothesis: If plants are placed in warmer solution, then the rate of photosynthesis will increase. Experimental Question: What factors affect the rate of photosynthesis? A student will have prior knowledge as to the equation describing the photosynthetic process as well as having a basic understanding of the scientific method. Consider environmental factors that you could manipulate during the lab. They are now ready to be used in your experimental set up.
What happens to the disks? Cathleen Beliveau, Catherine Collison, Clark Leazier, Lindsey White Question: Will heat affect the rate of photosynthesis? This was shown when the paper chromatography was done, the beet leaf trials had many different coloured pigments over the paper, vs the spinach leaf only a green pigment which represented that only chlorophyll was present. The combined trapping ability of the accessory pigments and the regular pigments chlorophyll A and B allows for a greater combined absorption of light, because there are more pigments trapping a greater range of light from the visible light spectrum. The bicarbonate solution acts as a source of dissolved carbon dioxide for photosynthesis. Leaves appear green because chlorophyll is a very poor absorber of green wavelengths, therefore it reflects green light the best. What types of organisms undergo photosynthesis? Photosynthesis is the conversion of light energy into chemical energy which is stored in the bonds of sugar. Therefore, they will remain at the concentrated area unless a lipid soluble solvent is present. The experiment should continue until all the disks are floating.
Put the leaf disks into the barrel of the syringe, and tap them down to the tip. This action forces the liquid into the interior of the leaf. Additional experiments using different colors of light or different light bulbs would be interesting, as the chlorophyll trap different kinds of lights at different rates. You should see tiny bubbles coming out of the leaf disks. There should be four lines on your graph. Tubes 4 through 6 were also filled with 0. Avoid the edges of the leaves or major veins.
Graphs show that the higher the intensity, the higher rate of photosynthesis. Preparation of the leaf disks: 1 Use the cork borer to cut out the number of disks needed for your experiment. Use only the firm, dark green areas of the leaf. As photosynthesis occurs oxygen gas is produced and as this is made in the deflated spinach leaves they are then inflated to float to the top of the beaker. Add 1 drop of dilute liquid soap to each solution avoid suds. If you would like to set up a control cup, for comparison, prepare a cup containing water with diluted detergent and spinach leaf disks that have not been infiltrated with carbon dioxide.
Students should be thinking about the question they will raise about the photosynthesis experiment and if an investigation can be designed to test their question. Without light energy, no photosynthesis will occur, so no more O 2 gas will be produced. Inside of the cell consists of chlorophyll and stroma. Tubes 3 through 6 were all exposed to the light and their absorbances went down over time. In the example below, that time would be about 11.
How will air return to these spaces? Purpose The purpose of the experiment is to determine the specific types of pigments found in a beet leaf and in a spinach leaf by using paper chromatography and two solvents: water soluble solvent and lipid soluble solvent. For comparison purposes, each lab group that does this procedure should report the time at which half 5 of the disks is floating. What evidence supports those claims summarize data? Leaves or disks cut from leaves will normally float in water because of these gases. Graph your data for the experiment. Both have a similar purpose: to trap light to ultimately convert it into energy. Green had some of the least productive results, which it to be expected since most plants reflect green light and therefore cannot use it in the light reactions of photosynthesis.
What will happen if you remove the air from these spaces? This results in less light during the day for the plant to undergo photosynthesis. This activity will allow students to measure the rate at which the photosynthesis process occurs. Brainstorming will bring out possible reasons and variables that would influence photosynthesis. Keep doing this until the leaf disks sink and remain in the bottom of the barrel to assure there is no more air. Dislodge any disks that stick to the side of the container. You don't have to eat your greens - you can bring them into the lab and use them for investigating photosynthesis instead. This carbon dioxide will be supplied by sodium bicarbonate dissolved in the water with the plant leaf disks 3 the stomata opening is controlled by the guard cells and that water, carbon dioxide and oxygen all pass through the stoma openings 4 food production for animals and humans on earth is dependent on plants.
Chlorophyll b passes its exited electrons to chlorophyll a, which passes its excited electrons to other molecules, which store the energy as chemical potential energy. The green lettuce has less chlorophyll in it than the red lettuce and spinach, as shown by its slightly lower average of floating disks per minute. Place 10 leaf disks into the syringe and pull in a small volume of the bicarbonate and soap solution. Add a drop of the detergent solution to this cup. Table I: Reading Distance in mm Time in minutes Absorbance Tube 2 Control 11.
If you remove the light source from the cup, the leaves eventually will sink. The absorbance of tube 6 went all the way down to 0. When exposed to light, the disks use carbon dioxide and water to produce oxygen and glucose. Hold the vacuum for a few seconds, and then release the plunger, letting it snap back see photos below. The teacher will now demonstrate to students the basic technique that will be used to measure the rate of photosynthesis. Release the vacuum so that the solution will enter the disks.
The disks will float when they have produced a measured amount of oxygen through photosynthesis. . X-axis is Time min and Y-axis is floating disks. All students will be guided to use this technique. Photorespiration, Warburg effect and glycolate. Analysis Analysis: To make comparisons between experiments, a standard point of reference is needed.