Thursday, November 28, 2019
Factor affecting photosynthesis free essay sample
Low light intensity lowers the rate of photosynthesis. As the intensity is increased the rate also increases. However, after reaching an intensity of 10,000 lux (lux is the unit for measuring light intensity) there is no effect on the rate. Very high intensity may, in fact, slow down the rate as it bleaches the chlorophyll. Normal sunlight (usually with an intensity of about 100,000 lux) is quite sufficient for a normal rate of photosynthesis. Open and Closed Stomata Sub Topics 1. Carbon Dioxide Concentration 2. Temperature 3. Chlorophyll Concentration 4. Water 5. Pollution. Application 7. Compensation Point Carbon Dioxide Concentration Back to Top In the atmosphere, the concentration of carbon dioxide ranges from . 03 to . 04 %. However, it is found that 0. 1% of carbon dioxide in the atmosphere increases the rate of photosynthesis significantly. This is achieved in the greenhouses which are enclosed chambers where plants are grown under controlled conditions. The concentration is increased by installing gas burners which liberate carbon dioxide as the gas burns. We will write a custom essay sample on Factor affecting photosynthesis or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Crops like tomatoes, lettuce are successfully grown in the greenhouses. These greenhouse crops are found to be bigger and better-yielding than their counterparts growing in natural conditions. The following graph shows how different concentrations affect the rate of photosynthesis. Light Intensity Temperature Back to Top An optimum temperature ranging from 25oC to 35oC is required for a good rate. At temperatures around 0oC the enzymes stop working and at very high temperatures the enzymes are denatured. Since both the stages of photosynthesis require enzyme activity, the temperature has an affect on the rate of photosynthesis. Graph Showing Effect of Temperature on Rate of Photosynthesis Chlorophyll Concentration Back to Top The concentration of chlorophyll affects the rate of reaction as they absorb the light energy without which the reactions cannot proceed. Lack of chlorophyll or deficiency of chlorophyll results in chlorosis or yellowing of leaves. It can occur due to disease, mineral deficiency or the natural process of aging (senescence). Lack of iron, magnesium, nitrogen and light affect the formation of chlorophyll and thereby causes chlorosis. Water Back to Top Water is an essential factor in photosynthesis. The effect of water can be understood by studying the yield of crops which is the direct result of photosynthetic activity. It is found that even slight deficiency of water results in significant reduction in the crop yield. The lack of water not only limits the amount of water but also the quantity of carbon dioxide. This is because in response to drying the leaves close their stomata in order to conserve water being lost as water vapour through them. Pollution Back to Top Pollution of the atmosphere with industrial gases has been found to result in as much as 15% loss. Soot can block stomata and reduce the transparency of the leaves. Some of the other pollutants are ozone and sulphur dioxide. In fact, lichens are very sensitive to sulphur dioxide in the atmosphere. Pollution of water affects the hydrophytes. The capacity of water to dissolve gases like carbon dioxide and oxygen is greatly affected. Application Back to Top Study of photosynthesis and the factors affecting it helps us understand the most important biochemical life sustaining processes. All plants and animals are dependent on the sun for energy. This energy is made available to them by the process of photosynthesis. Man, like other animals, is dependent on the plants for his food. Scientists are constantly working towards developing new varieties of crops which give better yield of crops. With the population explosion and resulting pressure on land resources, the percentage of land available for cultivation is reducing at an alarming rate. This means that in the restricted space, the crops have to yield more. All this has been possible so far with the understanding of the photosynthesis. Greenhouse plants and crops in unfriendly freezing conditions have been possible due to the study of the factors affecting photosynthesis. Studies have shown that there are a group of plants called the C4 plants which are more efficient in harnessing carbon dioxide from the atmosphere. Since the atmospheric level of the gas is only 0. 3 to 0. 4% and maximum crop yield is reported at 1% level, these plants are ideal for cultivation as they can draw maximum carbon dioxide from the atmosphere, greatly increasing the yield. One of the areas of current focus is the better understanding of the mechanism of C4 plants. Compensation Point Back to Top The rate of photosynthesis is not constant throughout the day. Its rate is affected by the intensity of light. The actual requirement of the light intensity for maximum photosynthesis in a plant depends on the type of plant and also on its habitat. Generally, average sunlight intensity is sufficient for photosynthesis except on rainy or cloudy days. The rate of photosynthesis increases with increasing intensity of light and decreases with decreasing intensity of light. During early morning or late evenings when the rate of photosynthesis becomes equal to the rate of respiration, there will not be any net exchange of gases (CO2 and O2) between the plant and the surrounding environment. The light intensity, at which the photosynthetic intake of carbon dioxide is equal to the respiratory output of carbon dioxide is called the compensation point. Introduction In this course work, I will be discussing how the concentration of carbon dioxide affects the rate of photosynthesis. To find this out I will do an experiment to find out how much oxygen a piece of Elodea (Canadian pondweed) produces over a set period under controlled supervision. Back Ground Knowledge All plants photosynthesise, They do this in order to create their own food by converting sunlight, carbon dioxide and water into glucose and oxygen, which is a by-product (6Co + 6H O a C H O + 6O ) Plants have a part in their cell called chloroplast which contain chlorophyll the diagram below explains: [IMAGE] What are the limiting factors of photosynthesis? Although the diagram shows you what you need for photosynthesis it does not tell you what the limiting factors are. The limiting factors in photosynthesis are carbon dioxide, water, light and chlorophyll. This is because up to a point the more of each factor that is available to the plant will result in an increase in the photosynthesizing rate. Why did I use pondweed? I used pondweed so I could measure the amount of oxygen it produced accurately. I can do this by catching the oxygen bubbles under water, because of this choosing an aquatic plant was the best choice. I will use 5cm of elodea because it is a big enough piece to get a measurable result. I will know how quickly the elodea has photosynthesised by taking readings of how much solution was left in the burette after 24 hours and again after 48 hours. Why use the sodium bicarbonate? I used sodium bicarbonate solution in the experiment because it reacts with water to make carbon dioxide, which meant I could control the amount of carbon dioxide available to the pondweed. However, because of the time limitations I got my results by sharing the class results, this meant that I had to use the following concentrations of sodium bicarbonate: 0% 1. 25% 0. 5% 1% 5%. I used these percentages so that I had a good range of percentages but this didnââ¬â¢t give very good results because I made a big jump from 1% to 5%. If I did the experiment, again I would use these percentages: 0% 0. 5% 1% 2% 3% 4%and 5% so that it had a steady increase. How will I control the variables other than the Co concentration? To control the other variables (water, light and chlorophyll). I will be using a set amount of water, I will be using the same lamps at the same voltage and I will be using a set amount of pondweed so that the amount of chlorophyll level should be the same. They will all have the same window letting in natural light and the temperature will be the same because they are in the same room. Plan I plan to set up an experiment using pondweed to see how much oxygen is produced over 24 hours and 48 hours. I will then put my results in tables and graphs to help me answer my main question. Preliminary In my preliminary experiment, I tested the concentrations I had chosen to check that the Elodea photosynthesised. I used a plastic funnel and a ray box, after using these in the preliminary I decided to replace them with a glass funnel that was transparent so that more light could get through. I also decided that a ray box was not giving out enough light because the elodea was not photosynthesising well and so I decided to change it to a desk lamp to give it a more directed and stronger light source. Here is a diagram of my preliminary experiment:- Here is a diagram of the experiment I used to get my results:- Method: 1. set up the equipment in the apparatus list as the diagram above. 2. Record the volume of solution at the start of the experiment 3. turn the light source on 4. record the volume of solution after 24 hours of the first recorded volume 5. Record the volume of solution after 24 hours of the second recorded volume Accuracy To make my results accurate I will be measuring the water level from the bottom of the meniscus. I will do this by taking the results with my eyes level to the bottom of the meniscus. I will repeat the experiment twice so that including the average I have three sets of results, which I will then plot on a graph. If the results do not turn out how I am expecting I will look back at my work to check any problems I may have had. I will be leaving my elodea for 2 days and taking readings after 24 hours and 48 hours. This is because it will give it a reasonable amount of time to photosynthesise. I will find out how much oxygen the plant has produced over that time by taking my original reading for O in the burette and deducting my readings at 24h and again at 48h. Prediction What do I expect to happen? I expect that as the sodium bicarbonate concentration increases that the rate of photosynthesis will increase until it hits its maximum rate of photosynthesis. I can tell this because as the sodium bicarbonate reacts with the water it will produce carbon dioxide, which will increase the rate of photosynthesis.
Sunday, November 24, 2019
Reflection paper Essay Example
Reflection paper Essay Example Reflection paper Essay Reflection paper Essay Name: Instructor: Course: Date: Reflection paper After learning about global awareness, I have come to appreciate the sense of vision. The eyesight is a fundamental sense in our bodies. It enables us do everything. Without sight, most of the things would be difficult to do and some would be impossible. For example, it would not be possible to drive or fly an aircraft. When I watch the blind people, I notice they always struggle to do some activities. For example, when they are reading, they have to use special books. Many books are written and printed normally. However, blind students find it almost impossible to find resources that are printed in Braille as these are quite inaccessible. Vision should not be taken for granted and it is not guaranteed. Those with sight should take care of their eyes and sight. They should eat healthy foods rich in nutrients for eyes and sight. It is our responsibility to help blind people in the society. We could help by donating fundamental facilities for them in their learning institutions. It is also important to help them in any other possible way. For example, helping them to walk across the road or anything else they need. Blind people are part of the society and they should not be set apart from other members of the community. When carrying out the vision experiment, I noticed a few things. Immediately I was blindfolded, I felt confused fro the first few moments. Seeing darkness made me feel uneasy and completely different. It made me realize light is also an important element of sight and it enables us to see clearly. Regardless of having vision, it is not possible to see without light. Lack of sight triggers sad or other negative emotions. When I was blindfolded, I felt sad since I was incapable of doing my usual activities. Sometimes blind people feel disappointed by the communityââ¬â¢s attitude towards them. They argue that people see them as inferior since they are disabled. Other individuals offer them mere pity as opposed to opportunities for which they are capable. Individuals and the society have effect to the rest of the world. This mostly applies to people with disabilities. A good number of them feel alienated because of various reasons. For instance, there are inadequate public facilities for them. The society has the duty to accept them and assist them in every possible way. For example, organizing charity would help in supporting the welfare of the disabled. A society is a small unit globally and it can influence other societies in the world. Creating awareness ensures all the communities on a global scale are conversant with the issues. Disabled people have a role in our society and they are not given enough attention. Some of them have great potential in many areas but they cannot exploit them. This happens because there are barriers. In many countries, there is a perception that disabled people are not capable. It is rare to get a leader with any major disability like vision. It becomes depressing for them since they feel the urge to exploit their potential (Powell, 89) . It is encouraging to see how the society and the world at large have supported disabled people. There are a good number of learning institutions in many countries. They help these people to become independent and fit in the community. For instance, Occasionally, Paralympics take place. Disable people from all over the world have a chance of participating. This is another way of how the society is effective globally. Diverse people meet and interact with each other. It is a good feeling when these people meet and share experiences. Such sports support disabled people financially. The participants are compensated attractively and this uplifts their living standards. Societies and communities should continue to support disabled people because they are part of the community. Some of them are relatives and close friends. We cannot just ignore them and watch them suffer.
Thursday, November 21, 2019
Book summary Essay Example | Topics and Well Written Essays - 1000 words
Book summary - Essay Example Mercator projections typically hanged on pentagon offices and classroom walls usually place the US in the middle where it is separated from Europe to its East by the big Atlantic Ocean and from Asia by to its West by the Pacific Ocean. Our preference for the perspective reflects a particular national egocentrism and has for a bigger part of the past two centuries made a recommendable deal of a strategic sense (Kaplan, 154). Through a big part of the 19th century, oceanic moats made possible the era of free security as a historian by the name C. Van Woodward called it. United States then projected much of its power primarily towards East Asia and Europe as it stepped on the World stage and grew stronger. In the 20th century, America would wage wars, cold and hot, aiming to protect vital regions against the dominion of hostile forces. Their earlier purposes, notwithstanding, the ancient maps are no longer meaningful having outlived their usefulness. After the cold war had come to an end, with much intensity and speed since 9/11, focus shifted towards South and Southeast Asia, the Middle East and towards the western Pacific waters. Robert D. Kaplan in monsoon argues that fresh ways of viewing the World are needed. This is needed mostly in seeing those parts that are integral elements despite being split by old projections (Kaplan, 165). Kaplanââ¬â¢s goal was providing his fellow countrymen with a similar map centered the Greater Indian Ocean, the region that stretched eastward right from the Horn of Africa going past the Arabian Peninsula, Iranian plateau as well as the Indian subcontinent going all the way to Indonesian archipelago and even beyond. He was glad that the monsoon winds shifted direction regularly at six month intervals, making connecting of the far-flung shores by waters to be readily navigable even when there were primitive sailing vessels. The greater Indian Ocean was initially linked by Muslim merchants, later Portugal
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