Category: Photosynthesis

Introduction

Photosynthesis is the process by which plants and some prokaryotes, such as bacteria and algae, use the light from the sun to produce energy rich food molecules, i.e., glucose, from carbon dioxide (CO₂) and water. The process also plays an important role in nature by forming a part of the nutrient cycle, e.g., the carbon, water, nitrogen, and oxygen cycles (Hames & Hooper, 2005). Since the process makes use of components of the environment, such as light, carbon dioxide, and water, it is obviously affected by these factors.

This paper tables the result of the study, which was conducted to ascertain the effect of carbon dioxide on the photosynthetic rate of waterweed. An aquatic plant was used due to its ability to absorb dissolved carbon dioxide and release oxygen, making it easy to count air bubbles evolved per minute. Terrestrial plants are devoid of both the mechanisms to sequester dissolved carbon dioxide and the ability to respire in water. In this experiment, it was hypothesized that the rate of photosynthesis rises with an increase in the concentration of carbon dioxide and went on to test the hypothesis.

It was assumed that during the experiment, the plant will be producing oxygen from photosynthesis as a byproduct and that the production of CO₂ was negligible. In addition, it was imperative to use a piece of waterweed that could exude bubbles of roughly equal size at a constant rate. A suitable sprig is the one that fits in experimental vessels and that has been cut at an angle at the time of collection. Cutting at an angle enhances the ability of the sprig to absorb water and stay viable longer by keeping the xylem vessels open (Hames & Hooper, 2005).

A more accurate approach to this experiment would have been estimating the amount of gas evolved by the plant in a given time, using the photosynthometer. Other than providing knowledge on how to design and conduct experiments to explore the effect of different environmental variables on the rate of photosynthesis, this experiment was also meant to help in connecting and applying theoretical concepts in a practical setup.

Background Information

Photosynthesis results in the production of energy rich molecules as shown in figure 1 below.

The energy rich molecules produced through photosynthesis make the plant biomass that constitutes the food and fuel for other organisms. Simply stated, without photosynthesis, there would be no life on earth. The conversion of light photons into chemical energy requires the presence and action of photosynthetic pigments. These pigments are chlorophylls and the accessory pigments carotene and xanthophylls (Hames & Hooper, 2005). The chlorophylls are a diverse group of pigments, existing in a variety of forms in photosynthetic organisms.

The commonest ones are chlorophylls a and b. Chlorophyll is the preferred pigment. The chlorophyll has two functions during photosynthesis; first, it absorbs red, violet, and some forms of blue light, and second, it converts the absorbed light into the form that can be used further by cells. Hames and Hooper (2005) noted that “these functions are accomplished by a number of alterations to the basic structure of the core unit, the tetrapyrrole ring” (p. 390).

They further found out that the variations gave chlorophylls and bacteriochlorophylls a few useful characteristics. Thus, chlorophylls are capable of absorbing light at longer wavelengths than heme, are easily excited by light, and are membrane-bound (Hames & Hooper, 2005). The accessory pigments function to increase the array of wavelengths from which plants can harness energy.

Plants have leaves whose cells possess special structures, namely, the chloroplasts that are the sites of photosynthesis. Detailed studies on the structure of chloroplast have shown that the chlorophyll molecules are arranged out on pairs of parallel membranes (thylakoids) that form grana (Roberts & King, 2007). This arrangement offers maximum surface in a minimum volume.

Thus, grana harbor chlorophyll and enzymes that are involved in the light-dependent stage (photoreaction) of photosynthesis. Another part of the chloroplast that is important is the stroma. It holds enzymes for the light-independent stage (synthesis reaction) and is the site for this reaction (Roberts & King, 2007). In plant leaves, chloroplasts are mainly concentrated in the loosely packed palisade and spongy mesophyll cells, making these cells the chief photosynthetic cells. Similarly, the leaves have stomatal openings that permit the exchange of gases between the plant and the environment, ensuring that carbon dioxide is freely accessed by the plant.

The other raw material may be water or other electron donor. In this view, the process of photosynthesis is said to be either oxygenic or anoxygenic (Roberts & King, 2007). Plant roots absorb water, which is the other raw material for oxygenic photosynthesis. The xylem tissue and other specialized cells transport the absorbed water from the roots to the leaves. In this process, light energy transfers electrons from water to carbon dioxide, which produces carbohydrates and oxygen. On the contrary, anoxygenic photosynthesis uses other molecules such as hydrogen sulfide as electron donors. In this regard, it does not yield oxygen.

The process of oxygenic photosynthesis can be summarized in a simplified equation as shown below:

From the equation, one can tell that the rate of photosynthesis can be measured by either monitoring consumption of reactants such as carbon dioxide and water, or by monitoring the rate of products, namely, carbohydrates, or oxygen released. In the present experiment, the investigator focused on the oxygen emitted because it constituted the measured variable in the experiment. In the aquatic plants, oxygen production can easily be visualized as bubbles of air rising to the surface of the water.

Thus, calculating the bubbles of oxygen that are produced in a given time can be used as a measure of the rate of photosynthesis in a plant. In aquatic environments, CO₂ is often in short supply for the plants that grow there because the gas is very soluble in water but has a slow diffusion rate once in solution form. Therefore, insufficient carbon dioxide may be a limiting factor in the growth rate of plants inhabiting such areas. Hydrogen carbonate ions constitute one source of CO₂ and contribute to its concentration in water, as it constitutes the minerals found in soils, rocks that form the floor of water bodies, and rainwater.

Materials and Method

In this experiment, carbon dioxide was added into a beaker with water containing a branch of waterweed. The branch of waterweed was placed in a transparent cylinder and a test tube was inserted inside the water and held by a stand. Different rates of carbon dioxide, i.e. 3ml, 6ml, and 10ml per 600ml of water were used. The investigator used a stopwatch to measure time in intervals of 5 minutes for each treatment and counted the amount of air bubbles produced by the plant as it photosynthesized.

Results/Process Data

As stated above, three different rates of carbon dioxide in 600ml of water were used and the amount of oxygen evolved by the plant measured in a 5-minute time span in each case. The raw data obtained during the experiments is presented in table 1 below.

A table showing the raw data obtained during the experiments. (R1 = Round 1, etc)

Processed Data/Sample Calculations

The datasets were used to compute different parameters to analyze the rate of photosynthesis in the waterweed under different conditions of carbon dioxide and the results illustrated in tabular and graphical forms as shown. The mean/average number of bubbles of oxygen produced is computed using the formula

For instance, the sum (∑) of all oxygen counts at 3ml CO₂/600ml concentration is 1346. Dividing this result by the number of rounds the counts made (n), which in this case was 20 gives a mean of 67.3.

Mean = 1346/20 = 67.3.

Thus, the mean is 67.3 as shown in the table. The same was done for the data on other concentrations to obtain their means. A similar approach was employed to calculate the median, modes, variance, and standard deviations for the datasets but using the formulae for each arithmetic operation. To be confident that the mean obtained in each case was a true mean for the datasets, the standard error of the mean (SEM) was calculated. The statistic was computed by dividing the standard deviation by the square root of the sample size:

SEM =

Therefore, the standard error of mean for the 3ml CO₂/ 600ml water concentration would be:

SEM = 5,4046/√20

SEM = 1.2085

Thus, the standard errors of mean for our three datasets are 1.2085, 0.6856, and 1.0965, respectively. The data that does not vary a lot, for example, the data recorded for 6ml CO₂ will have a smaller SEM implying that we are more confident that the mean calculated is a representation of the true mean of the data.

Table 2: Statistical Analysis of the Experimental Data

A table of the computed mean, median, mode, variance, standard deviation and the standard error of mean for the data obtained when the waterweed was subjected to varying concentration of carbon dioxide. A graphical representation of these data is given in figure 2 below.

This figure shows the comparison between numbers of bubbles of oxygen produced by the plant as a function of carbon dioxide concentration that the branch was subjected to. An important point to note is the high number of oxygen bubbles counted when the plant was supplied with 10ml CO₂. The oxygen bubble numbers were highest in 10ml CO₂, followed by 6ml CO₂, and then 3ml CO₂.

Discussion

The role of photosynthesis is to trap solar energy and introduce it into the ecosystem through the synthesis of carbohydrates and precursors of other biomolecules that are useful in the constitution of bodies of living organisms (Mauseth, 2008). The process of photosynthesis proceeds in two distinct phases. During the light reaction (photoreaction), light absorbed by the chlorophyll is used to hydrolyze the water molecules to yield hydrogen ions, oxygen, and free electrons.

The electrons move to the NADP⁺ to yield NADPH.

The light reactions are catalyzed by a series of enzymes and proteins that constitute the photosynthetic electron transport chain (ETC). The light dependent reaction can be summarized as shown below indicating the transfer of electrons from water to NADP⁺.

In addition to the products shown above, the electron transport chain activities/light reaction yields ATP. In summary, in photoreaction, electrons are removed from chlorophyll and may be reverted to chlorophyll via carriers (ETC proteins) with the assembly of ATP (cyclic photophosphorylation) or combined with hydrogen ions from the hydrolysis of water to form hydrogen atoms for the dark reaction (non-cyclic photophosphorylation) (Roberts & King, 2007). The hydrogen atoms are carried in the form of reduced NADP+ to the dark stage, a process involving electron transfer via chlorophyll photosystems I and II (Roberts & King, 2007).

The second phase of photosynthesis (carbon-fixation or synthesis reaction) utilizes ATP and NADPH from the photoreaction to convert carbon dioxide into the simple sugar glucose that is processed further to obtain sucrose and starch (Hames & Hooper, 2005).

The two molecules of glyceraldehyde 3 phosphate condense to form glucose, which then polymerize to form sucrose. Extensive polymerization yields starch. Glucose and other products of photosynthesis can be channeled to other biosynthetic pathways such as protein, lipid, nucleic acids, and lecithin biosynthesis. It may also be consumed by other organisms and be used in production of energy during respiration and in the manufacture of other biomacromolecules in these organisms.

Photosynthesis yields all the oxygen that organisms breathe in the atmosphere. Moreover, the power of the process has been a subject of scientific investigation for some time with researchers attempting to (1) utilize the photosynthetic organisms to produce pollution-free burning fuels like methane or hydrogen, and (2) develop simulated photosynthetic systems capable of sinking the CO₂ content of fuels or polymers by capturing CO₂ using nanotechnology (Mauseth, 2008).

From the above equations, it is evident that the rate of photosynthesis can be affected by other factors such as availability of water, light intensity, light color, and temperature in addition to CO₂ concentration (Mauseth, 2008). However, in the present experiment, we were concerned with the effect of levels of CO2 on the rate of photosynthesis in waterweed. Therefore, other physical factors such as light intensity, the color of light, PH of the solution, and temperature had to be kept constant so as not to interfere with the inferences.

Biological variables which were either assumed or kept constant included leaf color (chlorophyll content in the branch), leaf size and age, stomata density and distribution, and the leaf variegation (Roberts & King, 2007). Variation in the method that were worth noting included how long the shoot remained viable for repeated experimental procedure, the size of the shoot, and the method of data collection. The choice of the water weed to use in the experiment is important. Though any aquatic plant, e.g., Elodea can be used, Cabomba, a tropical pondweed that can be obtained from aquatic shops is the best since it has a significantly higher rate of photosynthesis that can be monitored easily by observing the oxygen gas that is produced.

Evaluation

The results of the experiment agree with the assumption made at the start of the experiments, namely, the rate of photosynthesis increases with the increase in the levels of CO₂. At any one given round of counting, the number of oxygen bubbles recorded was highest at 10ml CO₂, followed by 6ml CO₂, and lastly 3ml CO₂. The average/mean counts of bubbles of oxygen produced at each CO2 concentration were 98, 87, and 67 for 10ml, 6ml, and 3ml CO₂ concentrations, respectively. One can tell that the bubbles produced are oxygen by testing the gas.

In addition, because oxygen is the only gas produced during the light reaction of photosynthesis, it can be concluded that the bubbles emitted contained the gas. As water is hydrolyzed, oxygen is produced as a waste product. During the day when plants are actively photosynthesizing, much of the carbon dioxide produced during cellular respiration does not diffuse out of the plant body; instead, it is retained for use in photosynthesis. Therefore, the impact of CO₂ from respiration on the experimental results was insignificant, or it was assumed so.

Based on the results, one can safely conclude that increasing the level of carbon (IV) oxide results in a concomitant increase in the rate of photosynthesis. The reasoning behind this conclusion is that CO₂ is a reactant in the Calvin cycle to synthesize glucose. Therefore, its availability in high concentration means that dark stage of photosynthesis proceeds unhampered. There are no inhibitory feedback signals sent from the dark stage of the photoreaction, heralding the need for reduced rate of activity at the photoreaction.

The result is that the light dependent reaction proceeds at higher rate leading to high levels of O₂ being produced as CO2 concentration availed to the plant increases, Hence, the CO₂ level that resulted in the fastest rate of photosynthesis is 10ml/600ml water. At the start of the experiment, diverse bubble counts were made for each concentration of CO₂. These scenarios are evident when one observes the shapes of the graphs above. The underlying explanation relate to the fact that at the start of the experiment, the branch was adjusting to the light intensity and temperature of the experimental setup.

From the graphs and the data, one can notice that with time the rate of photosynthesis at 10ml CO₂ and 6ml CO₂ almost equal each other. This may be because other than CO₂, there are other factors that influence photosynthesis and may be the limiting factors responsible for the slowing rate of photosynthesis at the highest carbon dioxide concentration. Another possible explanation for this could be due to the counting errors made by the investigator.

Conclusion

Overall, photosynthesis, just like any other chemical reaction, is affected by the dynamics of its reactants and products. Increases in the concentration of reactants, CO₂ included, results in a concomitant increase in the rate of photosynthesis until the optimum activity is reached whereby the reaction trails off because of the limitations of other factors. Similarly, accumulations of the products act as negative feedback mechanisms that slow down the rate of the reaction.

References

Hames, D., & Hooper, N. (2005). Photosynthesis. Bios Instant Notes Biochemistry. New York, USA: Taylor & Francis Group.

Mauseth, J. D. (2008). Photosynthesis. Botany: An Introduction to Plant Biology. Sudbury, Massachusetts: Jones And Bartlett Publishers.

Roberts, M. B. V., & King, T.J. (2007). Autotrophic Nutrition. Biology: A Functional Approach. Students’ Manual. Cambridge, UK: Thomas Nelson & Sons Publishers.

The selected article pertains to the topic of photosynthesis, making it a relevant and significant piece of text on the biological subject. In sum, it highlights the concept of actively utilizing bamboos to reverse the polluting nature of the construction industry since these plants capture carbon from the atmosphere to build their rigid biostructures (TDT par. 8). Firstly, it is important to begin the comment with a focus on photosynthesis, which is an essentially biological process. I think that bamboos’ exceptional ability to capture carbon faster than any other vegetation is worth using in a demanding industry of construction. Photosynthesis is the very first step of enabling the usability of sunlight energy within a biosphere. In other words, the sun’s radiation in photons is transferred to chemical energy held with the bonds of an organic molecule. Bamboo is the fastest growing plant, which is often confused with a tree, but it is technically grass. Knowing the fact that the majority of a plant’s structure is made from polysaccharides, specifically cellulose, it is evident that bamboo is an efficient producer of glucose. Therefore, the photosynthesis process can output a substantial amount of glucose chains only if it is capturing a significant amount of carbon dioxide from the atmosphere because the carbon in glucose comes from this gas.

Secondly, throughout the course, I learned that a photosynthetic reaction not only captures carbon dioxide and sunlight energy to create a glucose molecule but also releases oxygen into the air as a byproduct. Considering the fact that cellular respiration requires oxygen to facilitate the electron chain transport reaction to extract ATP from glucose, the photosynthetic exceptionalism of bamboos is unparalleled. Therefore, I think that bamboo’s rate of photosynthetic activity and efficiency requires further and in-depth research and analysis (TDT par. 6). It is clear that its high carbon-capturing capability coupled with its usability in the construction industry, which is known to cause pollution, makes the plant a powerful solution to climate change.

Thirdly, I am convinced there is no more significant process on Earth that has laid links between animate and inanimate nature than the photosynthesis of green plants. Photosynthetic plant organisms with the participation of green pigments of chlorophylls capture the unlimited cosmic light energy of sunlight, assimilating inorganic compounds of terrestrial origin, creating organic substances with electromagnetic light energy stored in them in chemical bonds, which feed themselves and all life on Earth. Without exaggeration, we can say that photosynthesis is a perpetual motion machine and the preserver of life on Earth. In addition, photosynthesis plays the role of an environment-forming factor in the Earth’s biosphere, providing gas homeostasis of the atmosphere, absorbing carbon dioxide, the respiration product of all living organisms, and releasing oxygen, which is necessary for aerobically breathing living organisms. In addition, the oxygen it gives off maintains an ozone shield that protects all living things from the harmful effects of ultraviolet rays. The latter created the conditions for the emergence of life from the ocean on the Earth’s land surface.

Fourthly, I should note that photosynthesis, being an ecological environment-forming factor in the biosphere itself, is directly dependent on external environmental factors. The ecology of photosynthesis itself is a consequence of the interaction of photosynthetic plants with specific environmental conditions, which must be clearly known as a way of its regulation and effective productivity in various natural environments. It is important to note that any organism, including a photosynthetic plant organism, such as bamboo, is in an environment that is a complex of environmental conditions that affect life. The complex of conditions is made up of elements of environmental factors. Such factors that act on the body cause adaptive reactions in them are called environmental factors. Environmental factors can be abiotic, such as light, temperature, environmental pH, salinity, atmospheric pressure, soil and air humidity, and wind, that is, factors of inanimate nature. Biotic factors include the impact of living beings and anthropogenic associated with human activities, leading to a change in nature as a habitat. The action of environmental factors can stimulate the life processes of plants, and limit, slowing them down. Light, temperature, moisture, and edaphic factors are considered to be the main factors of the photosynthesis process.

Lastly, I think bamboo’s photosynthetic exceptionalism is manifested in the fact that light is one of the most important factors of photosynthesis, as it is a source of the necessary radiant energy for biochemical processes. In other words, it participates in the formation of organic substances. In the life of a plant, it is important that there is enough light so that in the process of photosynthesis, they produce more substance than is necessary for the flow of respiration costs. There must be an obligatory positive balance, without which the growth and existence of a plant are unthinkable. For the process of plant photosynthesis, it is highly important that there are no zones on Earth where plants cannot grow due to lack of light.

Work Cited

TDT. “Planting Bamboo Can Combat Climate Change.” The Daily Tribune, Web.

Biochemistry is a science that explains the biochemical processes that happen within the smallest unit of a living organism (plants or animals). These processes occur as metabolic pathways characterized by “a series of chemical reactions occurring within a cell” (Audesirk and Byers 4). Examples of these pathways include among others glycolysis, photosynthesis and respiration. These reactions are catalyzed by enzymes “which require the provision of such elements as minerals and vitamins which make them function optimally” (Audesirk and Byers 4). Since these processes incorporate chemicals, these pathways are quite intricate. Against this backdrop, we frame our thesis statement which explores the complexity of photosynthesis and respiration as metabolic pathways.

By definition, photosynthesis is a process whereby light energy (of blue and red wavelength) is converted to chemical energy in presence of CO₂ and water. This process occurs in plants and green algae eventuating in the formation of sugars. Basically, photosynthesis in plants happens at the chloroplast which contains chlorophyll (green pigment) vital in absorbing light energy.

Principally, the chemical reaction that happens in the chlorophyll is typified by the equation: 6CO₂ + 6H₂O + light energy C₆H₁₂O₆ + 6O₂. However, this process is quite complex than what meets the eye since it involves two processes: light and dark reactions. The light reaction “happens at the thylakoid membrane, and it serves to convert light into chemical energy” (Audesirk and Byers 5). This energy is then passed onto the central chlorophyll where photosynthesis happens, producing energy that is stored as ATP (adenosine triphosphate). The dark reaction which happens in the absence of light but inside the stroma utilizes CO₂ and ATP to form sugars (glucose) in what is referred to as the Calvin Cycle (Fig. 1) (Audesirk and Byers 5).

The overall reaction that happens in the cycle is shown in the equation below:

“3CO₂ + 6NADPH + 5H₂O + 9ATP →glyceraldehyde-3-phosphate (G3P) + 2H⁺ + 6NADP⁺ + 9ADP + 8Pi” (Audesirk and Byers 5)

To utilize the sugars processed by plants, animals and plants alike initiate respiration processes which can either be aerobic or anaerobic as manifested in most microorganisms. However, the scope of this paper limits itself to aerobic respiration; a process whereby glucose/organic substrate is broken down in the presence of oxygen to release energy, and molecules of water and CO₂. The energy is stored chemically as ATP and hence, can be used by other cells within an animal/plant. Basically, in a simplified equation the below reaction occurs:

C₆H₁₂O₆ + 6O_{2 →} 6CO₂ + 6H₂O + Energy

Akin to photosynthesis, respiration is a complex phenomenon that involves two processes: glycolysis which eventuates in the formation of pyruvic acid from glucose and a process of oxidizing the product to CO₂, NADH, and H₂O (Fig. 2). The NADH molecules are utilized in both the electron transport chain and chemiosmosis processes to yield ATP molecules. Of note, this process occurs in the mitochondrion of a cell. This process is summarized as below in a Citric Cycle. The process raw material, pyruvate molecule, is a product of glycolysis. The pyruvate molecule undergoes a decarboxylation reaction courtesy of an enzyme (pyruvate dehydrogenase) to produce acetyl-CoA that is fed in the cycle to finally produce ATP.

In a conclusion, as typified in the cycles above, the metabolic pathways are complex. While the Calvin Cycle is responsible for the manufacture of sugars in plants, the Citric Cycle is a metabolic pathway vital in the utilization of the manufactured sugar to produce energy. Either cycle incorporates several chemical compounds to produce their respective products.

Works Cited

Audesirk, Thomas, and Byers Baldin. Biology – Life on earth with physiology. San Francisco, CA: Benjamin Cummings, 2008. Print.

Doutor, Silva. The major metabolic pathways. Cambridge: Cambridge University Press, 2009. Print.

Introduction

The natural photosynthesis process changes light energy into chemical energy. However, in recent times, there are ongoing active studies in the field of artificial photosynthesis. Chemical energy originates from the breakdown of CO2 and H20 under light energy. The process results in the production of carbohydrates for plants alongside oxygen that is aerobic in living organisms. However, the minor details of the energy-transformation processes at the molecular level remain unclear.

Recent Advances

Latest advances in specific areas of spectroscopy, crystallography, and molecular genetics have provided new opportunities for scientists to explore artificial photosynthesis. Specifically, scientists strive to use the known and change them into “functional, efficient, synthetic systems that will tap the endless supply of energy coming from the sun”.[1] Researchers believe that artificial photosynthesis can work on a large scale and generate energy to serve the needs of human. An example of the possible exploitation of artificial photosynthesis to generate energy is the use of photovoltaic (PV) cells. However, researchers have cited high costs and the occasional absence of the sun as limiting factors to harvesting solar energy.

The demand for clean energy has pushed many researchers to focus on artificial photosynthesis as a possible source of clean energy that can replace fossil fuels. Thus, artificial photosynthesis could be the solution to the world’s energy challenges.

Michael Berger observes that recent approaches focus on titanium dioxide as a possible photocatalytic material due to its relatively “low cost, chemical stability, and photostability”.[2] However, the availability of the ultraviolet (UV) limits the application of this technology on a large-scale (about four percent of the world’s region has solar UV). This makes the technology impractical on a large scale.

Other researchers have focused on the exploitation of tungsten trioxide as new photoanode material. Still, others have considered tungsten trioxide as “a mixture material with titanium dioxide for splitting water because it can offer relatively small bandgap (∼2.5 eV) and corrosion stability in the aqueous solution”.[3] While tungsten trioxide has exhibited a major potential in artificial photosynthesis, its quantum remains low. A new study with titanium oxide nanotubes with tungsten oxide has shown a significant improvement in artificial photosynthesis.

Meanwhile, there are ongoing efforts to use varied tungsten trioxide or titanium dioxide to boost the effectiveness of electrochromic impacts and photocurrent in water solutions. Some scientists at the University of Texas have shown that carbon with elements of titanium dioxide (TiO2) nanotubes have abilities to enhance photocurrent densities. Still, these researchers also used “titanium oxide nanotubes with tungsten oxide (WO3) as photoanode” [4]to demonstrate solar harvesting techniques. The result indicated that such nanocomposite materials were effective and stable methods of trapping solar energy. [5]

Challenges

Researchers have faced many challenges despite their numerous contributions to artificial photosynthesis. These challenges are mainly critical science and financial issues. However, this is an emerging technology. Therefore, artificial photosynthesis still has many challenges to conquer in the future before it can be commercially viable.

In the US, in 2011, President Obama designated funds for the Joint Center for Artificial Photosynthesis (JCAP), which consists of Berkeley Lab and Cal Tech. [6]Researchers have concentrated on imitating chloroplast and enhancing its operations. Chlorophylls can retain sunlight and facilitate water breakdown processes efficiently. Several catalysts facilitate the photolysis process. In addition, there is a chloroplast that has elements, which can transfer electrons, detach hydrogen ions for the adenosine triphosphate process, and maintain the arrangement of the cells. This is what many researchers aspire to imitate.

For instance, JCAP scientists want to develop various parts and join them to form a prototype for “scalable and cost‐effective solar fuel generators without the use of rare materials or wires and robustly produces fuel from the sun that is ten times more efficient than typical current crops”.[7]

The major issue for cells that absorb light is the caustic nature of aqueous elements when reactions take place. In addition, nanophotovoltaic (nanoPV) cells cannot stick to catalytic surfaces properly. Researchers at the Berkeley Lab have developed both organic and inorganic PV elements in order to enhance charge transfer, durability, and efficiency.

In addition to existing challenges, another major obstacle is the development of an effective catalyst for artificial photosynthesis. The catalyst should enhance reaction, electron portability, and should not be from rare and expensive metal like platinum. Moreover, such catalyst should be long lasting and able to withstand rapid reaction that involves photooxidation. Still, such a catalyst should have the ability to yield the maximum chemical energy from low activities. Such challenges have pushed scientists to develop new approaches, which can efficiently control the catalyst and account for the entire chemical reaction that occurs.

The future research should focus on developing advanced methods of enhancing nano structures and various coating elements, which have low band gap and are stable during reaction and in aqueous medium.

Artificial photosynthesis now works

Most scientists have dedicated their resources to enhance the effectiveness of the photosynthesis process through artificial photosynthesis. Artificial photosynthesis has attracted the attention of all researchers across developed nations. In the past, these researchers have achieved mixed results. The challenge has been developing an effective catalyzer for facilitating the process of artificial photosynthesis. Such a catalyzer can allow scientists to overcome challenges in achieving functional artificial photosynthesis. [1]

In Sweden, a group of researchers from the Royal Institute of Technology in Stockholm developed “a molecular catalyzer that could oxidize water quickly”.[2] These researchers reported that their advances had achieved “over 300 turnovers per second with the newly equipped artificial photosynthesis”.[3] They claimed that the natural photosynthesis could achieve between 100 and 400 turnovers per second. Therefore, their molecular catalyzer remained exceptional.

These scientists believe that the outcome of their research has provided the groundwork for revolutionary development in artificial photosynthesis. The development of a catalyzer can transform many aspects of energy production. For instance, the catalyzer can produce hydrogen in mass, allow express changes of solar energy to hydrogen, or facilitate the generation of electric energy. The only challenge is how to develop a cost-effective catalyzer.

Scientists have also developed an artificial leaf during research in artificial photosynthesis. Artificial leaf has existed for a while. However, new studies have transformed materials and altered the process to develop economically viable projects.

The artificial leaf has “a nickel-molybdenum-zinc compound and cobalt film on different sides together with sunlight absorption materials”[4] between the two compounds. The side with the “nickel-molybdenum-zinc releases hydrogen gas, whereas the side with the cobalt film releases oxygen gas during the photolysis”.[5] The resultant gas generates the required electricity.

Daniel Nocera, a researcher at the Massachusetts Institute of Technology believes that the use of nickel-molybdenum-zinc element for generating hydrogen gas is an important development because it eliminates the need for a platinum catalyst, which is an expensive catalyst. [6] Such materials are readily available and affordable. The new project also has longer and continuous operating hours of at least 45 hours than the previous version that could only go for barely a single day. [7]

Researchers in artificial photosynthesis believe that artificial photosynthesis shall meet the energy requirements of the world in the future. The only challenge is how to make artificial photosynthesis cost-effective in the future.

Implications

Such advances in artificial photosynthesis have significant implications to researchers. For instance, the ability to generate hydrogen gas from inexpensive shall allow for mass production of the gas for generating electricity. As new ideas emerge, artificial photosynthesis would provide alternative energy or replace fossil fuels. Therefore, funding research in artificial photosynthesis is necessary for solving global energy needs.

Conclusion

The fundamental research has provided technologies that allow us to comprehend the intricate photochemistry that involves the normal photosynthesis. Still, recent advances in artificial photosynthesis show that researchers can develop methods of generating energy from photovoltaic solar cells.

Such advances have shown steady progress as researchers seek available and affordable catalysts for generating hydrogen. Thus, the major challenges to artificial photosynthesis and its implications are funds and research development. Therefore, scientists must make gains in the laboratory real by designing “solar fuel generation systems with the required efficiency, scalability, and sustainability to be economically viable in order to create a breakthrough that could have a revolutionary impact on humanity’s energy systems”.¹

Reference List

Addison, G, FB Marcia, AB Barbara, and E Edward, Science at the frontier, National Academy Press, Washington, D.C.,1992.

American Chemical Society, Secrets of the first practical artificial leaf, Science Daily, 2012. Web.

Bapna, M, A Breakthrough for Renewable Energy? Insight WRI, 2012. Web.

Berger, M, Nanotechnology advances the efforts to achieve artificial photosynthesis, Nano Werk, 2006. Web.

Charlie C, C Jung and S Dong, Clean Energy from Simulating the Leaf: Artificial Photosynthesis, Berkeley, 2012. Web.

Matthew, TM, Y Lin, G Yuan and D Wang, ‘Forming Heterojunctions at the Nanoscale for Improved Photoelectrochemical Water Splitting by Semiconductor Materials: Case Studies on Hematite’, Accounts of Chemical Research, 2013.

Nida, R, and I Lee, Artificial Photosynthesis Now a Reality, Berkeley, 2012. Web.

Nocera, DG, ‘The Artificial Leaf’, Accounts of Chemical Research, vol. 45, no. 5, 2012, pp. 767–776.

Osterloh, FE, ‘Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting’, Chemical Society Reviews, vol. 6, no. 42, 2013, pp. 2294-2320.

Footnotes

TM Matthew, Y Lin, G Yuan and D Wang, ‘Forming Heterojunctions at the Nanoscale for Improved Photoelectrochemical Water Splitting by Semiconductor Materials: Case Studies on Hematite’, Accounts of Chemical Research, 2013.

Introduction

Many factors indeed directly or indirectly affect the photosynthetic rate in terrestrial plants. Ordinarily, there exist opposing conditions that influence photosynthetic rates. It is worth noting that photosynthesis is a multi-step process that needs carbon dioxide, sunlight and water as substrates. The release of oxygen and energy as by-products occurs after the process is complete. The energy can subsequently be converted into sucrose, glucose or any of the many other sugar molecules. Photosynthesis is the cause of this composition, without which the amount of oxygen in the air would be as low as below five percent. Consequently, carbon dioxide levels would be very high; enough to exterminate the entire mammalian life; this makes the process to be one of the defining features of the plant kingdom.

Study Objectives

This study attempts to investigate the factors influencing the photosynthetic rate. In this regard, one is expected to establish the necessities of photosynthesis and discover the requirement of carbon dioxide and light for oxygen evolution. The objectives to be employed in the study include:

1. To investigate light as a limiting factor in oxygen evolution
2. To examine carbon dioxide as a limiting factor in oxygen evolution
3. To explore geographical location of species of plants as a limiting factor in oxygen evolution
4. To investigate effects of LED distance as a limiting factor in oxygen evolution

Hypothesis

• Null (H₀) hypothesis: Geographical location, LED distance, and treatment of Light and Carbon dioxide have no statistically significant effect on oxygen evolution at 5% level of precision
• Alternative (H_A) hypothesis: Geographical location, LED distance, and treatment of Light and Carbon dioxide have statistically significant effects on oxygen evolution at 5% level of precision

Variables

• Dependent variable– rate of oxygen evolution
• Independent variables –
  • Light availability
  • Quantity of carbon dioxide available
  • Distance from the source of LED light
  • Type of Plant Species

Results and Analysis

The above analyses have been conducted using Stata version 11. Two sample t-tests have been carried out on the test parameters to either accept or reject the null hypotheses regarding the oxygen evolution process.

1. Light dependence of oxygen evolution– considering Cabomba species, both in darkness and Red light, the probability value is 0.8664, which is above the critical value of 0.05 at 5% significance level. Therefore, we accept the null hypothesis, and conclude that statistically; there is no significant impact of light on oxygen evolution process at 5% level of precision (See Appendix 1).
2. Effect of increased carbon dioxide on oxygen evolution– for the normal and treatment values of group 4, the probability value is 0.3413, which is above the critical value of 0.05 at 5% significance level. Thus, we confirm the null hypothesis, and establish that statistically; there is no significant impact of increased carbon dioxide on oxygen evolution process at 5% level of precision (See Appendix 2).
3. The rate of oxygen evolution on the geographical location of species of plants– considering group 4 values of cerata and Cabomba species, subjected to an equal wavelength of green light, the probability value is 0.1817, which is above the critical value of 0.05 at 5% significance level. Hence, we agree with the null hypothesis, and affirm that statistically; there is no significant difference in the rate of oxygen evolution process in different plant species at 5% level of precision (See Appendix 3).
4. The rate of oxygen evolution on distance from the source of light– considering Red and Blue LED distances of cerata species, the probability value is 0.3117, which is above the critical value of 0.05 at 5% significance level. As a result, we accept the null hypothesis, and confirm that statistically; there is no significant difference in the rate of oxygen evolution process when the distance between the sources of light to the plant species is altered proportionately at 5% level of precision (See Appendix 4).

Discussion of Results

Light as a Limiting Factor of Photosynthesis

Light is a limiting aspect, particularly when its amount is too little to let the light-dependent effect carry on at its optimum rate. Even though some photosynthesis will continue in the absence of light, the rate will be much lower as compared to when the light was sufficient and the distance shorter. Such mostly happens with plants in the forest under other plants.

Distance as a Limiting Factor of Photosynthesis

Different LED lights have different wavelengths; hence, varying the distance from the lamps is purposely done to ensure that it is not a limiting element in the photosynthesis.

Carbon Dioxide as a Limiting Factor of Photosynthesis

NaHCO3 boosts the availability of carbon dioxide and ensures that it is not a limiting aspect of the reaction. Plain water might not have sufficient oxygen to facilitate the occurrence of the utmost photosynthetic rate. Hence, it eradicates the limitation factor.

Type of Plant Species as a Limiting Factor of Photosynthesis

The biogeographic distribution of plant species reflects their specific climatic adaption, making them possess a particular set of intrinsic characteristics. This explains why not any tree grows anywhere. The geographic adaptation affects the position of leaves on trees, which in turn influences photosynthesis. These two plant species were specifically used to ensure that they were not the limiting factors of the photosynthesis process.

Conclusion

All the independent variables in this experiment are the main limiting factors in the photosynthesis process. Their inadequate supply will tend to reduce the photosynthetic rate or process, and the reverse is true.

Questions

• Experimental controls used in this study include the use of pond water only, as well as covering the test tubes with a dark cloth. By fixing or eliminating them, it makes it easier to identify precisely the relationship between independent and dependent variables. A control is, therefore, part of the experiment that tests whether the system behaves as it should (Smith & Dukes, 2013).
• Taking a dark reading before every LED reading attempts to serve two main purposes:
  • It shows that the system is behaving as one would expect from previous experience, knowledge and observation to allow an interpretation of the experiments.
  • In case something is incorrect, it ensures that it is possible to identify the experimental inaccuracy so that it can be rectified the next time it is done.
    LED lamps were positioned at different distances to determine the effect of the varying light intensities on the photosynthetic rate.
• The null and alternate hypotheses encompass:
  • Null (H₀) hypothesis: Treatment of Light has no statistically significant effect on oxygen evolution at 5% level of precision
    Alternative (H_A) hypothesis: Treatment of Light has a statistically significant effect on oxygen evolution at 5% level of precision
  • Null (H₀) hypothesis: Treatment of Carbon dioxide has no statistically significant effect on oxygen evolution at 5% level of precision
    Alternative (H_A) hypothesis: Treatment of Carbon dioxide has a statistically significant effect on oxygen evolution at 5% level of precision
  • Null (H₀) hypothesis: Geographical location of species of plants has no statistically significant effect on oxygen evolution at 5% level of precision
    Alternative (H_A) hypothesis: Geographical location of species of plants has a statistically significant effect on oxygen evolution at 5% level of precision
  • Null (H₀) hypothesis: LED distance has no statistically significant effect on oxygen evolution at 5% level of precision
    Alternative (H_A) hypothesis: LED distance has a statistically significant effect on oxygen evolution at 5% level of precision

The t-test is a two-way test because of the uncertainty about the results of the experiment (Smith & Dukes, 2013). The alternate hypothesis could either be less than or greater than zero.

Reference

Smith, N. G., & Dukes, J. S. (2013). Plant respiration and photosynthesis in global‐scale models: Incorporating acclimation to temperature and CO2. Global Change Biology, 19(1), 45-63.

Appendices

• Produce a figure with an appropriate figure legend of your TLC plate that could be published in a scientific journal.
  • Indicate all relevant information, e.g.origin, solvent front. You can use e.g. Power-Point, Photoshop or Illustrator or similar software for his task
  • Identify and label the different pigments observed
  • Identify the samples spotted in the different lanes.
  • Write a concise figure legend with a minimal number of words that allows the reader to understand what he sees. Note: Do not repeat all details of the methods in the legend!

• 2. What pigments were observed in the chlorophyll extract? What is the function of each of these pigments?

• What does the removal of Mg²⁺from the tetrapyrrole ring using cation exchange chromatography tell you about the bonds holding the Mg²⁺ in place?

The removal of Mg²⁺ implies that the bonds holding these cations onto the tetrapyrrole ring are weak. Mg²⁺ ions are positively charged ions found in the tetrapyrrole ring in the chlorophyll structure. The resin utilized in the strong ion-exchange chromatography contained negative charges. The negatively charged molecules strongly attracted the positively charged Mg²⁺ from the tetrapyrrole ring. Therefore, it is easy for the anions in the chromatography resin to attract and remove the Mg²⁺ from the ring. It has been demonstrated that chemical bonding plays a crucial role in the structural integrity of compounds. Compounds with weak chemical bonds are easily destabilized by other chemicals. On the other hand, compounds with strong chemical bonds are strong and are not easily destabilized by other chemicals.

• Why are the chlorophyll pigments green?

Chlorophyll pigments absorb light at specific wavelengths. The pigments capture violet to blue (400-500 nm) and orange to red (650-700 nm). It has been demonstrated that chlorophyll pigments absorb colours at different light wavelengths. However, green light is not absorbed by the pigments. It is reflected by chlorophyll pigments. The reflection of green light by chlorophyll pigments makes them appear green. The spectrum at which chlorophyll pigments absorb light energy from the sunlight helps categorise them.

• A compound is added to the coupled photosystem of plants that binds to the reduced plastoquinone(PQH₂) produced by photosystem II and prevents it from interacting with the other components. Briefly explain what this would do to the functioning of the coupled photosystem and to the plant. Assume that there is excess compound compared to the amount of plastoquinonepresent.

Photosystem II in photosynthesis is started when charges are separated between P680 and pheophytin. The process of charge separation occurs quite fast to ensure quick and constant transfer of components released in light and dark stages of photosynthesis. Plastoquinone is essential in preventing charges from recombining in photosystem II. The binding of the inhibiting compound will prevent plastoquinone from detaching from reaction centre into the inner water hating part of the membrane. When plastoquinone accepts an electron at the QA-site, it is moved to a different chemical molecule at the QB-site. The photosystem II process is maintained by cycling of electrons and protons between the QA-site and QB-site. The functioning of the coupled system will be inhibited because the process of electron transfer in photosystem II will be altered. Excess inhibiting compound compared to the amount of plastoquinone will arrest functioning of plastoquinone and culminate in cessation of photosynthesis in the affected plant.

Photosynthesis is one of the primary sources of energy for living organisms. The fossilized photosynthetic fuels account for almost 90% of the energy in the world (Johnson, 2016). Cellular respiration is a process that takes place in the living organism and converts nutrients into energy. This essay will examine photosynthesis and cellular respiration separately and identify similarities, differences, and interconnectedness between two processes. Two processes are similar in that they both deals with energy, but they are different because one process involves catabolic reactions and another anabolic one.

The purpose of photosynthesis is to convert atmospheric carbon dioxide into carbohydrates using light energy. The light splits one of the reactants, water in the mesophyll of the leaf into oxygen, electrons, and protons during the light-dependent phase (Johnson, 2016). Then carbon dioxide enters the mesophyll of the leaf through openings, stomata, during the light-independent phase. These two reactions differ in light utilization and molecules production. The first reaction products are oxygen, adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH) that are used as energy storages, while by the end of the second reaction, the carbohydrate is obtained, and molecules mentioned above are used (Flügge et al., 2016). Photosynthesis occurs in the chloroplast with the light-dependent reaction taking place in the thylakoid membrane, and light-independent reaction in the stroma. The energy produced in the light reaction is used to fix carbon dioxide and produce carbohydrates while oxygen is released outside. According to the following equation of the photosynthesis, C → O2 + 2H20 + photons (CH2O)n + electrons + O2 carbon monoxide and water are transferred into carbohydrates under the light with the release of atmospheric oxygen.

The purpose of cellular respiration is to convert nutrients into energy. The reactants of the respiration are glucose circulating in the blood and oxygen obtained from breathing, while the product is ATP. Cellular respiration starts from glycolysis in the mitochondria’s stroma, where the glucose is broken down into pyruvate (Bentley & Connaughton, 2017). Then it continues with the citric acid cycle that generates ATP, NADH, and FADH2. In the final stage, the electron transport chain uses these molecules to generate more ATP. The energy produced is then used for metabolic processes in the organism, while carbon dioxide is released with breathing (BBC Bitesize, n.d.). According to the following equation of the cellular respiration, C → 6H12O6 + 6O2 6CO2 + 6H2O the glucose is broken down into carbon dioxide and water with the presence of oxygen.

There are two main differences between photosynthesis and cellular respiration. The first one is the anabolic process, during which complex compounds are synthesized, while the second one is catabolic, which involves breaking down the compounds (Panawala, 2017). The second crucial difference is that photosynthesis is found only in chloroplasts, while cellular respiration is found in any living cell, making it a universal process. There are also two main similarities between photosynthesis and respiration. The first similarity is that both processes involve the production of ATP (Stauffer et al., 2018). The second similarity is that both processes utilize ATP but for different purposes.

Photosynthesis and cellular respiration are connected in such a way that they allow to perform metabolic functions normally. Moreover, these processes help to regulate the concentration of oxygen and carbon dioxide in the atmosphere. If photosynthesis stopped occurring, the level of oxygen would drop dramatically This would lead to deaths of all living organisms whose lives depend on this molecule. Whereas if cellular respiration stopped happening, living creatures would not be able to generate energy and sustain life.

To conclude, photosynthesis plays a crucial role in maintaining life on Earth. Photosynthesis uses light energy to produce oxygen, while cellular respiration uses oxygen to break down complex molecules and provide energy. These processes are different in their metabolic nature, but similar in terms of energy storage. If photosynthesis did not exist, the life for oxygen-dependent creatures would become extinct. Similarly, in the case of cellular respiration disappearing, living organisms would not be able to produce energy.

References

BBC Bitesize. (n.d.). Respiration. 2020. Web.

Bentley, M., & Connaughton, V, P. (2017). A simple way for students to visualize cellular respiration: Adapting the board game MousetrapTM to model complexity. CourseSource. 4, 1-6. Web.

Flügge, W., Westhoff, P., & Leister, D. (2016). Recent advances in understanding photosynthesis. F1000 Research, 5, 1-10.

Johnson, M. P. (2016). Photosynthesis. Essays Biochemistry, 60(3), 255-273.

Panawala, L. (2017). Difference between photosynthesis and respiration. IE PEDIAA. Web.

Stauffer S., Gardner A., Ungu D.A.K., López-Córdoba A., & Heim M. (2018). Cellular respiration. In Labster virtual lab experiments: Basic biology (pp. 43-55). Springer.

Introduction

Photosynthesis is a biological process in which plants utilize the available carbon dioxide in the atmosphere to give out oxygen. There is also the presence of a green pigment called chlorophyll is involved in the transfer of unutilized energy to utilizable chemical energy. Mostly the process of photosynthesis involves the utilization of water to release oxygen that we depend on for our lives. Plants which are the only photosynthetic organism to have leaves are viewed as a solar collector packed with photosynthetic cells. For this process to occur, the following raw material should be available; water and carbon dioxide which after entering the leaf cell it produces oxygen found in the atmosphere. During the process water from the soil is taken up by the roots all the way to the leaves via the xylem. In order for the plants not to dry out they use the stoma so that they can exchange gases. Stomata are the only way in which oxygen can get their way out of the leaf. However during this process a great amount of water is lost. This can be witnessed by the cottonwood trees in dry seasons by loosing a total of 100 gallons daily(Kramer & Kozlowski, 1960).

Discussion

When you consider this process we can classify plants to be carbon sinks because they play a great role of utilizing the carbon dioxide found in oceans and atmosphere. Plants are also involved in production of carbon dioxide through respiration and used by photosynthesis they too convert energy absorbed from the sunlight into chemical energy with covalent bonds and other carbon dioxide sources includes animals. Carbonates in the ocean are formed so that they can balance the presence carbon dioxide and oxygen in the atmosphere. (Smith, 1984).

Carbon dioxide plays different roles in the plants life cycle. Though in many debates it has never been revealed how higher level of carbon dioxide will benefit the Earth. This is true because food crops, flowers and trees depend mostly on carbon dioxide. According to the Voluminous scientist, evidence shows that when the amount of carbon dioxide in the atmosphere rises above the current level the rate of plant growth will increase and enlarge due to more efficient photosynthesis and reduced water loss. Extreme temperatures will not harm plants, there will be faster growth rates and pollutants and excessive nutrients will not injure plants. Increased carbon dioxide in the atmosphere is projected to increase plant productivity, increases the size of a leaf and thickness, the heights of a stem and seed production. This will also lead to an increase in the both numbers and sizes of fruits and flowers (Smith, 1984).

It is also important to note that, though plants through the process of photosynthesis produces oxygen, they will only survive for a few days without oxygen even if everything is provided. If this goes on for sometimes they cannot stay alive. Plants differ from animals due to their abilities to make their own nutrients through the process of photosynthesis. Through this carbohydrates is produced and it’s broken down by plants to get energy. During this process food is created and a reaction is needed so that the created food can be broken down into usable form, and this process requires oxygen, water and nutrients (Wittwer, 1992).

The above discussed can also be applied to people where by they cannot survive without plants. Plants and animals are the two main kingdoms of life. The Earth consists of more than 300,000 species of plant and they can create their own food by means of energy from sunlight. All oxygen is generated by plants. They also make life on the Earth possible by providing humans with food as well as building material. This plant kingdom has different species which can be grouped into; mosses and liverworts, ferns, cone plants and flowering plants (Wittwer, 1992).

According to me life is made possible by plants for example forests and grasslands which supplies oxygen. According Scientists and conservationists if deforestation goes on without control the survival system on the Earth will be injured. In addition to this plants also act as source of food to the people for example fruits, leaves, roots and tuber, seeds and barks too. Plants can also be seen contributing to the survival of the people whereby they make seeds which are transported to different places of the world spreading it. They are sources of energy, People also depend on plants by exchanging gifts in form of flowers, plants be of assistance when it comes to people surviving the harsh conditions.

Plants reduce the amount of noise in the urban setting and add the aesthetic value to the environment. They also contribute towards the ecology of an area by their roots stabilizing the soils which prevent soil erosion. They also reduce the speed of wind which is mostly used by farmers and provide them with income.

Conclusion

With all this, I would conclude that it will be impossible to say that people can survive without plants. This is so because people need oxygen, food, shelter, building material et cetera which is provided by plants. Therefore I will urge everyone to protect all the trees found on Earth by avoiding degrading activities for example; deforestating and polluting forested areas. By doing so, we will be promoting a healthy life to everyone (Wittwer, 1992).

References

Kramer, P.J. & Kozlowski, T. (1960). Physiology of trees. New York, NY: McGraw Hill.

Smith, W.H. (1984). Pollutant uptake by plants: In air pollution and plant life. New York, NY: John Wiley.

Wittwer, S.H. (1992). Rising carbon dioxide is great for plants. Journal of Biology, 12(6), 1-9.

According to extant literature, runaway photosynthesis describes a scenario in which the machinery of photosynthesis could be adversely affected by shifts in the environment, leading to the crumbling of all ecosystems that depend on it for survival (Dartnell, 2011). In particular, the expression “runaway photosynthesis” is mainly used in the mainstream media and by environmental experts with reference to positive or negative feedback effects that could affect the photosynthesis process due to changes occurring within the environment (Cox et al., 2011). This paper illuminates how the phenomenon of runaway photosynthesis affects life in the universe.

Animal life as is known today requires an atmosphere with adequate oxygen, whereas plants require a sufficient amount of carbon in the atmosphere in the form of carbon dioxide (CO₂) for photosynthesis to occur (Global Climate Change, 2002). Scientific investigations have proved that vegetation and soil contain about three times as much carbon as the atmosphere, and that at the present time the land is absorbing about a quarter of anthropogenic CO₂ emissions released by various activities in the biosphere because uptake of CO₂ by plant photosynthesis is surpassing respiration from soils (Cox et al., 2011).

However, as acknowledged by Cox et al (2011), a number of scholars “have discussed the possibility of the land carbon sink either saturating or reversing primarily because of the potential for accelerated decomposition of soil organic matter under global warming” (p. 155). Such a scenario could definitely lead to runaway photosynthesis not only due to lack of a stable habitable temperature occasioned by the unstable mixture of greenhouse gases, but also because of the probability that “feedbacks” between the climate and the land biosphere may substantially accelerate or suppress atmospheric CO₂ and land carbon uptake (Dartnell, 2011).

The problem of runway photosynthesis lies in its capacity to substantially accelerate atmospheric CO₂, leading to the negative effects of global warming and dangers associated with greenhouse emissions. Cox et al (2011) note that “whilst increases in atmospheric CO₂ are expected to enhance photosynthesis (and reduce transpiration), the associated climate warming is likely to increase plant and soil respiration” (p. 155). Climate warming as a direct consequence of sudden drop in photosynthesis and reduced removal of carbon dioxide from the atmosphere is known to expose animal species to the harmful ultraviolet (UV) light and could also make life on earth impossible as too much carbon in the atmosphere is disastrous to life (Dartnell, 2011; Global Climate Change, 2002). A runway greenhouse effect occasioned by too much carbon in the atmosphere will certainly cause the earth’s surface temperature to rise to levels that cannot sustain plant or animal life on earth.

According to available literature, “it is estimated that photosynthesis is a sink for around 60 billion tons of carbon every year, by far the strongest mechanism for carbon dioxide removal from the atmosphere” (Global Climate Change, 2002 para. 2). However, although increases in the level of carbon dioxide in the atmosphere is good for plant growth, a lack of balance between the increases and the respiration of animals may have the capacity to trigger runaway photosynthesis and hence destroy many species that live in very sensitive ecological niches. For example, small shifts in temperature rise or precipitation drastically affect the capacity of Oak tress to survive, not mentioning that an increase of as little as 1°C in ocean temperature over two or three days could “bleach” corals due to loss of their symbiotic algae which is fundamental for their nutrition. Humans cannot survive under extreme temperatures or within environments with a very high volume of carbon dioxide (Global Climate Change, 2002). Essentially, therefore, the phenomenon of runaway photosynthesis adversely affects life in the universe in multiple ways, hence the urgent need to preserve the environment.

References

Cox, P.M., Huntingford, C., & Jones, C.D. (2004). Conditions for sink-to-source transitions and runaway feedbacks from the land carbon cycle. In H.J. Schellnhuber & V.P. Cramer (Eds.), Avoiding dangerous climate change: Key vulnerabilities of the climate systems and critical thresholds (pp. 155-176). Cambridge: Cambridge University Press.

Dartnell, L. (2011). Astrobiology: Exploring life in the universe. New York, NY: The Rosen Publishing Group.

Global Climate Change. (2002). Overview of climate change research: Biosphere. Web.

Introduction

Photosynthesis is the process by which plants assemble carbon-based compounds which are the building blocks and energy stores of life. Plants first entrap sunlight energy and convert it to a chemical energy in ATP molecules which are in form of bonds. ATP brings energy to reactions where glucose is formed from water and carbon dioxide. To finish, glucose molecules are combined to form starch and other molecules. Oxygen is also produced during photosynthesis which is released in to the atmosphere (Koning, 1994, p. 1). The process of photosynthesis is summarized in the equation below;

12 H₂O+6 CO₂ →→6 O₂+C₆H₁₂O₆+6H₂O

Aerobic respiration is a procedure of cellular respiration that utilizes oxygen to split molecules to release electrons and form energy (Gregory, 2006, p. 2). In this process adenosine triphosphate (ATP) is produced which is liable for storing up and transporting most energy to other body cells. Aerobic respiration has two by-products which are water and carbon dioxide. It usually involves three main stages of reactions glycolysis which include the Kreb’s cycle and electron transport phosphorylation. The equation below is a summary of aerobic respiration;

C₆H₁₂O₆+6O₂ →→6CO₂+6H₂O

How the two processes are linked between plants and animals based on the reactants and products of both pathways

The two processes are the life blood of plants and animals. These processes link in the way that the by-products of one process are used as the raw materials of the other. Photosynthesis uses carbon dioxide and water from aerobic respiration to produce oxygen, food (glucose) and water. Whereas aerobic respiration in animals will require glucose and oxygen from photosynthesis to produce energy (ATP molecules) as well as carbon dioxide and water used again in photosynthesis.

A description of how energy is transferred from sunlight to ATP, from ATP to sugars, and from sugars to your cells

Sunlight is trapped by organelles called chloroplasts in the form of chlorophyll (a red and blue light) to start the process of photosynthesis. In this process molecules of carbon dioxide gas and water are combined in the presence of the solar energy and chemical energy is formed. Calvin cycle then takes place to convert ATP to sugars through carbon fixation where 6 molecules of carbon dioxide are combined with Ribulose Biphosphate to form Phosphoglycerate (PGA) (Bergman, 1999, p. 1). It is then converted into G3P (Glyceraldehyde-3-phosphate) which is a sugar. The sugars are then consumed by human beings in the form of starch.

The role of fermentation in allowing an organism to generate energy for its cell(s) in the absence of oxygen

In the deficiency of oxygen, pyruvic acid can be converted into compounds such as lactic acid through the combination of glycolysis and other additional pathways in the process of fermentation. This is important during exercise especially because breathing cannot provide the body with all the oxygen needed for aerobic respiration and the cells turn to lactic acid fermentation, therefore providing the muscles with the energy required in exercise.

How the energy from the sun ends up as chemical energy for the anaerobic organism or cell

Before fermentation occurs, one glucose molecule is split into two pyruvate molecules through glycolysis summarized as;

C₆H₁₂O₆+2 ADP_i+2 P+2NAD⁺ →2CH₃COCOO^– + 2ATP +2NADH + 2H₂O +2H⁺

Thereafter, fermentation can take place where sugars are converted into cellular energy producing carbon dioxide and ethanol because of the absence of oxygen as shown below (Paustian,2000, p.2);

C₁₂H₂₂O₁₁+H₂O+Invertase^→2C₆H₁₂O₆

C₆H₁₂0₆+Zymase→2C₂H₅OH+2CO₂

How an enzyme catalyzes a reaction

During a reaction a substrate that requires processing is carried towards the enzymes. Enzymes accelerate reactions via lowering the free energy of activation barrier, which is the Ea barrier (Kornberg, 1989, p.198). The enzymes are substrate definite and therefore can just speed up the creation of one form of a substrate. Usually, weak hydrogen or ionic bonds join the substrate to the enzyme. Then the enzyme lessens the Ea Barrier of a reaction by appropriately adjusting the substrates, damaging substrate bonds, giving a good microenvironment for the reaction to occur in the optimum PH. temperature and I.E and participating thoroughly in the reaction.

There are three main steps of the cycle of enzyme-substrate interactions

1. Enzyme + substrate
2. Enzyme-substrate complex
3. Enzyme + product

How enzyme activity regulated by the cell

Cells regulate enzyme activity through end-product inhibition. The enzyme catalyzing one of the stages in the metabolic pathway is inhibited by the end-product.

Subsequently, if the quantity of product swells, the pathway is hindered and less is formed. If the quantity reduces, the inhibition is condensed and more is manufactured.

Additionally, the gene that produces the enzyme is possibly switched on or off by courier molecules for instance hormones.

Reference list

Bergman, J. (1999). ATP: The perfect energy currency for the cell; creation research society quarterly. Web.

Gregory, M. (2006). Cellular respiration. The biology web. Web.

Kornberg, A. (1989). For the love of enzymes. Harvard University Press. Cambridge, MA.

Koning, R. E. (1994). Respiration. Plant Physiology Information Website. Web.

Paustian, T. (2000). University of Wisconsin-Madison. Web.