Floating Leaf Disk

Title: The net rate of photosynthesis related to the light intensity.

Purpose: Determine the effect of light intensity on the rate of photosynthesis of the discs.

Background: Photosynthesis is the process of plants to convert light energy into chemical energy. When light is absorbed by leaf pigments, electrons within each photosystem are boosted to a higher energy level, which produces ATP and used to incorporate carbon dioxide into the process of Carbon fixation. As photosynthesis proceeds, oxygen is released into the interior of the leaf which changes its buoyancy causing the disks to rise.

Data statement: When the distance of the light from the beaker is 16 cm, the rate of the discs to float is faster than the rate of discs in the beaker that is 18cm away from the light resources. However, when the distance of the light about 9 cm, the rate of the float of the discs is slower than the discs that are in the beaker which is 16 cm away from the light.

Data shows a bell curve.


Questions:

1. Explain the process of carbon fixation.
   1. In the carbon fixation stage, carbon dioxide is attached to RuBP by the enzyme rubisco. Carbon atoms of carbon dioxide are fixed into organic compounds.
   2. Carbon fixation occurred in the light-independent reaction. The process of carbon fixation is taking the carbon dioxide, inorganic carbon, and tracking the inorganic carbon to an organic molecule, usually carbohydrate. Since a series of enzymes control the carbon fixation, Rubisco is responsible for fixing the carbon. Rubisco takes Carbon dioxide and adds to RuBP. After adding the carbon dioxide, the whole molecule will separate into two 3-carbon molecules called G3P.
2. Explain the process that causes the leaf discs to rise.
   1. As adding the sodium bicarbonate into the water,  the bicarbonate acts like carbon dioxide for photosynthesis to cause the leaf discs to sink. since the photosynthesis proceeds, oxygen is released into the interior of the leaf, which changes its buoyancy causing the disk to rise.
   2. Since the leaf discs received the light, the discs will proceed the photosynthesis to produce the oxygen. By using the light, the plant can convert carbon dioxide and water to carbohydrates and oxygen. Due to the photolysis, splitting the water using the light, H+ ions travel in the lumen, while the oxygen stays inside of the leaf which eventually changes the buoyancy of the leaf. 
3. What is the effect of darkness on photosynthesis? Explain
   1. Since the photosynthesis is to convert light energy into chemical energy by transforming water and carbon dioxide into glucose, the light resources are essential to the process. If there is no light, the photosynthesis will stop, and the discs in the darkness will not float and stayed at the bottom of the beaker.
4. If we were to boil the leaf discs, what kind of results would you expect? Why?
   1. Since the discs were boiled, there would be no spaces for gases, and all the leaf disks would sink. Because of the boiled leaf discs, the proteins that in the leaf will be denatured and not functional, which the photosynthesis would not occur
   2. By heating the water to boil the leaf discs, the heated water may break the enzyme inside of the discs because of the high temperature. If the enzyme got breaks down and changing the shape, then the photosynthesis of the leaf discs could not function anymore due to the high-level temperature enzyme within the plant will be denatured. Plant material will generally float in water because leaves have air in the spaces between cells, which helps them collect CO2 gas from their environment to use in photosynthesis. However, after boiling the leaf discs, the water from the liquid status turns into gases which the air will be extracted from the leave and become the vapor which is why there are no spaces for gases. 
5. How would light intensity affect the rate of photosynthesis?
   1. To reach a certain appropriate light intensity, the faster the rate of photosynthesis will happen because the light affected the proportion of the photosynthesis. If it is too high in intensity, then the water would get too hot and it would slow down the rate of photosynthesis. If there is not enough light intensity, then the rate would also slow down because it is not getting enough resources to do the reaction.  Since light is the major resources for the plant to convert the energy and produce ATP and NADPH to be used into the Calvin Cycle to produce glucose, enough light will give more advantages to help plants to produce glucose.
6. How do light intensity and the rate of photosynthesis relate to the position of the sun, both during the day and during the year?
1. The light intensity speeds up the rate of photosynthesis if the sun is shining down directly because there are more spaces for plants to get light resources. However, if there is no light for a day, then the photosynthesis will slow down. During the day photosynthesis is present and at night it does not. During winter days, the sun is further down in the sky, so the same circle of sunlight covers a wider area, so there is less light per plant and most of the plants died during this season because it is too cold and has fewer resources. In this case, those plants that are pointing straight at the sun have higher chances of growing better such as the season of spring. However, during the summer, since the sunlight is too strong to impact the plant, the water will evaporate which means there are not many resources of water for plants so that there are a lot of plants dried out during summer.
2. Since the earth is tilting, which means in the different seasons, the ground will receive an unusual amount of sunlight — the position of the planet directly related to the light intensity which determines the rate of photosynthesis in the different season for different regions. For example, the area in the north and south part of the earth received less sunlight than the city in the equator did due to the tilting position of the planet. The light intensity speeds up the rate of photosynthesis if the sun is shining down directly which is in the spring and summer when the sun is directly facing to the side of the earth. During the spring and summer, the equator area will get the most sunlight to compare with the north and south part because of the position of the earth, which means the light intensity will reach to the highest point for the plants, and the rate of the photosynthesis will also speed up. However, because of the revolution of the earth, in the winter and fall season, the ground is backing towards the sun which means the sunlight intensity will be less than the sunlight in the summer. Therefore, the rate of photosynthesis will be slow. During the day photosynthesis is present, and at night it does not because the sun only appears during the day but not the night. Due to the position of the earth, the tilting position, and the rotation of earth self, many places will get the sunlight but others will not.