Lab Report: Understanding Photosynthesis Gen Biology Lab Abstract: This lab was called photosynthesis: understanding photosynthesis. It is a highly complex process that needs to be broken down in many steps to understand how it works. This lab covers the big components in photosynthesis including carbon dioxide intake, light consumption, and varying pigmentation. Introduction: Photosynthesis is a huge concept to learn and understand in the field of biology. Plants have their own special way of using the ATP they produce.
Photosynthesis is a process where plants harness the sunlight they receive and they produce carbohydrates, as well as oxygen for living things and other plants. Now the sunlight ultimately powers the process of photosynthesis. Sir Isaac Newton was an English physicist that used a light prism and demonstrated how white light contains varying colors. These colors range from red at one end of the visible spectrum to the color violet at the other end. Then another spectrum was added called the electromagnetic spectrum (or a continuous spectrum) by James Clerk Maxwell; this included: cosmic rays, visible light, x-rays, and radio waves.
For plants to use sunlight, they have to absorb it. So pigments absorb light energy. Chlorophyll is a pigment in leaves that reflect green light waves. This is the most important pigment in photosynthesis and there are also accessory pigments used in plants. Also in this lab there is the internal and external anatomy of a typical leaf. Materials and methods: The first procedure dealt with the internal anatomy of a leaf. The materials needed are: colored pencils, a prepared slide of a leaf, and a compound microscope.
After obtaining the prepared slide of a leaf, we used a compound microscope to observe the leaf. Then we sketched the leaf and labeled the following structures: cuticle, epidermis, mesophyll, palisade parenchyma, spongy parenchyma, stomata, and guard cells. The next procedure dealt with the external leaf structure. The materials needed are: a dicot leaf, dissecting microscope or hand lens, and colored pencils. First we obtained a leaf from our instructor. Then we sketched the leaf and labeled the blade and petiole. The following procedure dealt with a chromatogram.
The materials needed are: a pencil, safety goggles, scissors, chromatography paper strip, capillary tube, spinach plant pigment extract, test tube, cork stopper, graduated cylinder, chromatography solvent (alternative isopropyl alcohol), metric ruler, stopwatch or clock with a secondhand, hook/fashioned paperclip, paper towels, test tube rack, and mortar and pestle. First we obtained a strip of chromatography paper and cut it so it would fit inside a test tube (with it barely touching the bottom of the tube). Also, when touching the strip, touch the sides only.
Then we attached (firmly) the top of the strip to a hook (or fashioned paperclip at bottom of the cork stopper). Make sure it fits in the test tube. Next we used the pencil to draw a faint line across the strip two centimeters from the bottom tip of the strip. We placed the cork and strip in place, and we put a mark on the test tube one centimeter below the top of the stopper. The next step was to place the strip of chromatography paper on a paper towel. Then dip a capillary tube into the plant pigment extract (spinach pigment extract) provided by the teacher.
The tube will fill on its own. We applied the extract to the pencil line on the paper, blew the strip dry, and repeated it three to four times until the line on the paper is a dark green. We used a graduated cylinder and carefully measures 5 milliliters of chromatography solvent to pour into the test tube. Then we placed the chromatography strip in the test tube, positioning it so the tip of the strip barely touched the solvent. Then we kept the test tube capped and put it in the test tube rack. We then observed as the solvent rose on the paper and we recorded our findings.
After the solvent has moved up to the line drawn on the paper, remove test tube and the paper from the test tube. We set aside the paper to let it dry. Then we identified the pigment bands, the migration, and the rate of migration. The proceeding activity dealt with leaf collection and pigments from native trees. The materials needed are: at least three leaf specimens collected from a nearby source and a piece of typing paper. First someone in our group took a walk around campus and collected three different leaves.
We then had to identify the plant specimens and smear them onto a piece of white typing paper. But right before smearing them, we observed them and described what we saw. We then recorded what we saw on the smeared paper. The least procedure dealt with the intake of carbon dioxide. The materials needed are: a test tube, a large leafy piece of Elodea, test tube rack, medicine dropper, 1% solution of phenol red (pH indicator), stopper, straw, and water. First fill two thirds of a test tube with water and place the Elodea in a tube. We added four to five drops of the phenol red to the test tube.
We inserted the straw into a test tube, and blew gently to release carbon dioxide into the tube. The water will become orange-yellow in color (more acidic) and carbonic acid is formed. Then immediately place the stopper on the test tube. Place the tube in a well-lit area for ten to twenty minutes and observe/record what happens. Results: Paper Chromatogram: Table 10. 1- Artificial Band Pigments Color Band| Pigment| Color| Migration (mm)| R1 Value| (1) One| Xanthophyllis| Yellow| 80mm| 4. 3| (2) Two | Chlorophyll b| Olive green | 20 mm| 4. 8| 3) Three| Chlorophyll a| Light green| 60 mm | 4. 3| (4) Four | Beta-carotene| Orange-yellow| 40 mm| 5. 3| The Solvent | Chromatography solvent | Chromatography solvent| Chromatography solvent| Chromatography solvent| The pigments from native leaves and leaf collection resulted in three different leaves: a fig leaf, dogwood leaf, and Jane magnolia leaf. The fig was described as green, huge, and almost perfectly shaped. Then the dogwood leaf was crunchy and a little brittle. Then the Jane magnolia was slightly brittle, yet soft at the same time.
When doing the color smears the results were that the fig was bright green, the dogwood was rusty brown-orange, and the Jane magnolia was dark yellow with hints of brown. The carbon dioxide uptake color changed from a pink to a light yellow. Discussion: When drawing/observing the internal and external leaf structures was used to discover what went into a leaf; this was to realize that structure determines structure. The chromatography experiment was designed to see the different pigments in plants and which determines how much sunlight is let in. This affects how successful photosynthesis was at the time.
Then the carbon dioxide experiment was to see how easily plants are effected by the amount of carbon dioxide in n their surroundings. Conclusion: Photosynthesis is a very complicated process for students to understand. But by understanding the factors/processes used in photosynthesis, we can all understand it easier. The uptake of carbon dioxide (depending on the amount) affects the rate of photosynthesis. Also another huge factor in the process of photosynthesis is sunlight. It helps determines on what pigments the plant possess and how much work they can do.
