Cellular Energetics is the broad term that encompasses both cellular respiration and photosynthesis and refers to how energy changes and reacts within cells. Cellular respiration is the process by which cells break down sugars (ATP) in order to produce energy for other chemical reactions. Cellular respiration takes place mainly in the mitochondria and the reactants in this process are oxygen and glucose and the main product in this process is ATP as well as waste products which include carbon dioxide and water. Almost all organisms perform cellular respiration.
There are two types of cellular respiration aerobic and anaerobic; aerobic respiration involves the use of oxygen to produce cellular energy, while anaerobic respiration does not need oxygen in order to produce energy. Aerobic respiration uses the energy released during electron transport in order to form ATP. Anaerobic respiration uses pyruvate in order to produce ATP, but this ATP cannot be catalyzed until another reaction known as fermentation occurs. Cellular respiration includes the processes of glycolysis, krebs cycle, and the electron transport chain.
Glycolysis is used to convert glucose to produce two pyruvate as well as 4 ATP’s and 2 NADH but uses 2 ATP to have a net product of 2 ATP and 2 NADH. The krebs cycle converts pyruvate to Acetyl CoA, which produces 2 ATP,8 NADH, and 2 FADH’s per glucose molecule. Electron transport Chain is the last and most important step of cellular respiration, it makes ATP with the movement of electrons from high energy to low energy that makes a proton gradient which makes ATP, this cannot occur unless oxygen is present.
Fermentation is an anaerobic process in which converts sugars into acids, alcohol, or alcohol. This process occurs in yeast and bacteria as well as muscle cells that have no oxygen left. In yeast fermentation produces ethyl alcohol and carbon dioxide from glucose and fructose. Fermentation in bacteria cells the process of fermentation produces ethanol, while in human muscle cells fermentation produces lactic acid in cells that have a short supply of oxygen. The different carbohydrates used in this experiment were glucose, fructose, lactose, galactose, sucrose, honey, and water.
Photosynthesis is the process by which plants and some other organisms convert light energy into ATP that is then used in cellular respiration. Photosynthesis occurs in plants as well as some bacteria and some protistans, photosynthesis takes place in the chloroplast in plant cells with the help of the pigment known as chlorophyll. The reactants used in photosynthesis are carbon dioxide and water as well as light energy, the products are glucose and oxygen. Photosystem 1 is a complex that uses light energy to help with electron transport.
Photosystem II actually occurs before photosystem 1 and is the first protein complex that uses light energy, and is located in the thylakoid membrane. The calvin cycle which is also referred to as the carbon reactions pathway this cycle uses free energy, NADPH, and CO2 to produce carbohydrate. (Reumann & Weber, 2006) The color of light affects photosynthesis, plants use only certain colors for photosynthesis. The color of light which are absorbed are violet, blue, and red; while green light is used less if not at all.
In this lab we used clear, red, blue, and green light in order to see which will create the highest rate of photosynthesis. Cellular respiration will occur at a more substantial rate in the carbohydrate compounds glucose, galactose and fructose then in the compounds lactose, sucrose, and honey. Due to the fact that glucose, galactose, and fructose are monosaccharides while lactose and sucrose are disaccharides and honey is a mixture of many sugars. Photosynthesis will happen at the highest rate in the blue light, while red will be second highest and green will be last.
This is due to the fact that chlorophyll absorbs blue light the best, red light at the second best rate, and does not absorb green barely any, if not at all. Methods In the first experiment we tested the rate of cellular respiration in different carbohydrate compounds in order to see which compound would produce the highest rate of cellular respiration through the process of fermentation. To do this experiment we had to use many different materials, these include: large test tubes, rubber stoppers with graduated pipettes, sugar solutions, and active yeast cultures.
Starting the experiment we added 10 mL of the yeast culture to the 7 large pipettes, we then added a volume of each different sugar solution to its respective test tube, and putting distilled water in the 7th tube which will act as a control. We then capped the tubes with a stopper and pipette and marked the starting position of each yeast culture (we put the starting point as 0 for each of these for the 0 time). After we completed these steps of the process we measured the volume of the solution in each pipette at 10 minute intervals for a total of 50 minutes.
The independent variables for this experiment are the different carbohydrate compounds, the control would be time and the yeast compound, and the dependent variable is the amount of CO2 produced through cellular respiration. In the next experiment we tested the effect of different colors of light filters on the rate of photosynthesis in elodea stalks. For this experiment we used five large diameter test tubes, 10mM sodium bicarbonate, light source, rubber stoppers with graduated pipettes, and elodea stalks. First, fill the five large test tubes to near the top with sodium bicarbonate.
Next, add 1 stalk of elodea to each tube, after this cap the tubes with the pipetted rubber stoppers. Mark the position of the solution in the pipette after each tube is capped (we put the starting point at 0 for each tube at the time 0 measurement). Then, place each capped tube equal distance from the light source to insure they all receive the same amount of light. Finally, measure the volume of the solution in each pipette at 10 minute intervals for 50 minutes. The independent variable in this experiment were the color filters, the controls are time, elodea stalks, and light source.
The dependent variable for this experiment was the amount of O2 produced through photosynthesis. Results In the first experiment where we measured the rates of cellular respiration the results were mostly as we expected, but there were a few surprises in these results as well. The carbohydrate with the highest rate of cellular respiration was glucose followed by fructose, honey, sucrose. Lactose, galactose, and water all had the same final rate of cellular respiration. Figure 1. The rate of cellular respiration over time in the carbohydrate compounds glucose, fructose, lactose, galactose, sucrose, honey, and water.
The final absorbance rates for glucose was 1. 8, fructose 1. 7, lactose 0. 6, galactose 0. 6, sucrose 1. 5, honey 1. 6, and water 0. 6. In the second experiment we measured the rate of photosynthesis through different colored light filters, the results were for the most part as expected, but a bit off due to human error. The color with the highest rate of photosynthesis through the production of oxygen was the clear (control), next was red, then blue, and finally green. These results are somewhat the expected outcome for the different colors, although not exactly.
Figure 2. The rate of photosynthesis in elodea plants with different color light filters which include clear, red, blue, and green. The color that produced the highest rate of photosynthesis was clear at . 48, then red at . 28, and finally green at . 15 Discussions/ Real World Connections The hypothesis for the cellular respiration relates to what was discussed earlier in the paper, because the hypothesis stated that the monosaccharides should have a higher rate of cellular respiration due to the fact that it should be metabolized quicker since it is a simple sugar.
The results of the experiment somewhat support the hypothesis as two of the monosaccharides (glucose and fructose) had the highest rates of cellular respiration, however galactose had the lowest rate of cellular respiration along with lactose and the control (water). Due to this fact the hypothesis must be rejected, because the final results do not fully support what the hypothesis states. The hypothesis for the photosynthesis portion relates to what was discussed earlier, by stating that the blue light showed produce the fastest rate of photosynthesis, while green should have very little if any photosynthesis occurring at all.
This relates to what was stated earlier, because in the introduction we learned that plants absorb blue rate at a higher rate than any other, and that they barely absorb any green light at all. The results however told a different story, as the light with the fastest rate of photosynthesis was the control (clear), next was red, then blue, and finally green. So as expected the green light produced the least amount of oxygen through photosynthesis, but unexpectedly the clear or control had the highest rate of photosynthesis, because of this the hypothesis must be rejected since the blue light did not produce the highest rate of photosynthesis.
However, the experiment was affected by human error due to the fact that the blue filter was more violet than blue. A real world example of the process of fermentation, which was used in the first experiment is the process of making alcohol. The sugars and starches are converted into alcohol by the enzymes in yeast. There are also real world examples of photosynthesis which include plants turning green during the warm weather. Relating to my career, cellular respiration has a strong correlation with my future career as a physical therapist.
This is shown by the lactic acid that becomes present in muscle cells after all the oxygen is used up. This relates to the area of physical therapy by the lactic acid in the cells building up over time causing fatigue in the body and possibly leading to injury. (Quinn & Quinn, 2015) In this lab the different things that I learned were that cellular respiration is dependent on many factors that will affect the overall rate at which it occurs and how the ATP is produced and used. I also learned that photosynthesis is dependent upon many environmental factors which includes temperature.