Diffusion and Osmosis Essay Example for Free

Diffusion and Osmosis Essay Diffusion and osmosis are very important in biological process. Diffusion is the movement of molecules or ions from a region of their high concentration to a region of their low concentration. Osmosis is the diffusion of water molecules across a semipermeable membrane. To gain a better understanding of diffusion and osmosis, we examine multiple experiments to show diffusion and osmosis in animal cell, plant cell and synthetic cell. In our first experiment, we weight a decalcified chicken egg and place 10% NaCl concentration. At every fifteen minutes intervals, we weight the egg and record that the weight decreases. In our second experiment, we use three slices of aquatic plant Elodea and add pond water one leaf, distilled water for the second and 20% NaCl for the third, then observe the cells of each leaf with a compound microscope. Under microscope, chloroplasts (green organelles) in Elodea tend to bound to the cell wall in pond water, spread all over the cell in distilled water, pull away from cell wall in 20% NaCl. In our last experiment, we use a dialysis bag that contains 30% glucose and starch solution then place into a beaker of water and iodine solution. We then remove the bag out of the beaker, and use two test tube which label BAG, BEAKER to perform a Benedict’s test. We place solution in the bag in the BAG tube, and solution in the beaker in the BEAKER tube and add a drop of Benedict’s reagent to each tube, then heat each test tube and observe a color change in each tube. These experiments show that movement of water of chicken egg cell and Elodea cell is â€Å"osmosis† and movement of molecules in dialysis bag and beaker is â€Å"diffusion†. INTRODUCTION Diffusion is involved in many biological processes occurring in single-celled to complex organism (cite this). It is a part in life that we need to know and understand how it works. Diffusion is the process by which molecules move from an area of high concentration to an area of low concentration (cite this). A branch of diffusion process is osmosis, which is the movement of water across a membrane which is selectively permeable (cite this). We are going to learn and get more information about diffusion osmosis by perform three experiments. We place a shell-less chicken egg in salt solution. We predict that water in the egg will move out the cell because this is a hypertonic solution, a greater concentration of osmotically active substance than the solution on the other side of membrane. Next, we are going have three slices of Elodea in each different solution: hypotonic, isotonic, hypertonic then we observe these reactions in the microscope. We predict that one will have chloroplasts (green organelles) bound to cell wall in hypotonic, one will have chloroplasts move in the cytoplasm, one will have cell wall remain intact and chloroplasts move away from cell wall. Third, we’re going to use a dialysis bag contains starch and glucose and place in water and iodine solution. After a Benedict test, we predict that there will be color change in these solutions. These experiments are easy to perform and they also give people enough information to gain better concepts of how diffusion works in animal cell, plant cell, and synthetic cell. METHODS First, we performed an experiment to show osmosis in animal cell. Our materials in this experiment were a decalcified egg, a 350mL beaker, 10% of NaCl solution, a triple beam balance, and a timer. We used the triple beam balance to weigh the egg. The weight of the egg was 77.3g at this time. Next, we placed the egg in the beaker that was filled with 250mL of 10% NaCl. We waited about fifteen minutes and then remove the egg out of the beaker. We dried off the water from the egg and placed the egg on the triple beam balance. The weight of the egg after fifteen minutes was 76.6g. We then placed the egg back in the beaker and repeated these steps every fifteen minutes intervals. At thirty minutes, the egg’s weight was 76.3g. At forty-five minutes, the weight was 76.2g. At sixty minutes, the weight was 76.1g. We recorded the data and calculated the percent change in egg weight by using the weight at the present time minus the previous weight all over the previous time and all multi ply to one hundred. We then graphed our data to show percent changes in weight of the egg. Next, we performed another experiment to show osmosis in a plant cell. We used leaf of the aquatic plant Elodea, pond water, distilled water, 20% NaCl solution, a compound microscope, a pair of forceps. First, we cut three small pieces from Elodea plant with forceps. We then carefully placed each piece onto the microscope slide glass. We added a small drop of pond water to one piece and labeled it â€Å"pond water†. We added a small drop of distilled water to another piece and labeled it â€Å"distilled water†. Last we added 20% NaCl to the last piece and labeled it â€Å"20% NaCl†. We waited for ten minutes and then we observed the cells of each piece of leaf under the microscope. We then sketched the cells of each piece as seen in the microscope. In our last experiment of diffusion of synthetic cell, we used a 30-cm strip of moist dialysis tubing, a string, 30 % glucose solution, starch solution, iodine solution, Benedict’s reagent, hot plate, 500-mL bea ker one-third filled with water, handled test tube holder, 3 standard test tubes, disposable transfer pipettes, two of 400-mL beakers to hold dialysis bag. First, we soaked the dialysis tubing in water and closed one end with a string, and let the other end open. Then we added four pipettesful of 30% glucose into the bag and four pipettesful of starch solution to the glucose in the bag. We gently mixed the contents and observed the color in the bag. Next, we add 300mL of water to 500mL beaker. We put some drops of iodine solution in the water and it turned into a brown color. After that, we placed the dialysis bag into the beaker and waited for thirty minutes. After thirty minutes, we moved the bag and let it stand in a dry beaker. We then recorded the data. Next, we used two test tube which labeled â€Å"BEAKER† and â€Å"BAG† for the Benedict’s test. We put two pipettesful of the bag solution in the BAG tube and two pipettesful of the beaker solution in the BEAKER tube. We added a drop of benedict’s reagent to each tube and heat them up in hot water for three minutes. After three minutes, we observed the co lor change and recorded our data. RESULTS In our first experiment with decalcified egg in 10% NaCl, we find that the weight of the shell-less egg decreases after every fifteen minutes time interval. At time zero, the egg has 77.3g but after fifteen minutes, the egg has 76.6, a -0.9% change in weight. At thirty minutes, the egg has 76.3g, a -0.4% change in weight. At forty-five minutes, the egg has 76.2g, a -0.1% change in weight. At sixty minutes, the egg has 76.1g, a -0.1% change in weight. In our second experiment with Elodea plant, we find that chloroplasts(green organelles) of Elodea cell in pond water moves close to cell wall. In distilled water, we find that chloroplasts (green organelles) of Elodea cell move freely through out in the cytoplasm but block by cell wall. We also find that chloroplasts (green organelles) of Elodea cell of in 20% NaCl moving away from the cell wall and form tightly in the central of cytoplasm. In our last experiment with dialysis tubing, we observe some color change. The bag solution, which contains glucose and starch, has a transparent original color, turns to transparent with some black dots as final color. After using the Benedicts reagent, the tube which contains the bag solution turns into an orange color.

Southwest :: essays research papers

Changes in cost and efficiency   Ã‚  Ã‚  Ã‚  Ã‚  The situation today in the airline industry is basically a price/cost war. Companies are battling to cut and keep their operating cost low in order to remain competitive in an industry that is strongly driven by price. The principal cost factors that drive the industry are labor and fuel. In terms of labor Neeleman, Jetblue’s CEO, said that â€Å"The biggest problem in the industry isn’t pay, its work rules†. Labor cost accounts for the 38% of the overall operating cost of an airline company. Depending on the system that a company uses, its labor cost and labor necessity will vary. The point-to-point systems requires less personnel and the aircraft is less time on the ground, and more in the air, being able to flight more times that those aircrafts flying under the hub-and-spoke system. The first system is widely used by the new low-cost carriers, while the hub-and-spoke is very typical of the traditional airlines (Appendix 1). Moreover, labor cost is rising, which increases the overall cost per seat (Wright, September 8, 2003). In terms of labor efficiency, low-cost carriers are reducing labor or either by e-ticketing or by doing what Southwest states on their contracts, any qualified employee can perform any function (load, unload, cleaning, etc) as needed (Thompson.2005).   Ã‚  Ã‚  Ã‚  Ã‚  The second, most important factor that determines the cost structure in the industry is fuel cost. It is said that for one-dollar increase in the price of a fuel barrel, is costs the industry a billion a year (Tang, C. April 11, 2005). Moreover, in the future, the price of fuel is expected to continue increasing, what will tighten even more profit margins.   Ã‚  Ã‚  Ã‚  Ã‚  What other companies have done to lower their cost is to eliminate meals. Instead, in short flights, snacks are served to the passengers, and in long-distance ones, costumers are allowed to bring food with them or buy it on board.

K to 12 Program Essay

The K to 12 Program covers Kindergarten and 12 years of basic education (six years of primary education, four years of Junior High School, and two years of Senior High School [SHS]) to provide sufficient time for mastery of concepts and skills, develop lifelong learners, and prepare graduates for tertiary education, middle-level skills development, employment, and entrepreneurship. Students are able to learn best through their first language, their Mother Tongue (MT). Twelve (12) MT languages have been introduced for SY 2012-2013: Bahasa Sug, Bikol, Cebuano, Chabacano, Hiligaynon, Iloko, Kapampangan, Maguindanaoan, Meranao, Pangasinense, Tagalog, and Waray. Other local languages will be added in succeeding school years. Aside from the Mother Tongue, English and Filipino are taught as subjects starting Grade 1, with a focus on oral fluency. From Grades 4 to 6, English and Filipino are gradually introduced as languages of instruction. Both will become primary languages of instruction in Junior High School (JHS) and Senior High School (SHS). After Grade 1, every student can read in his or her Mother Tongue. Learning in Mother Tongue also serves as the foundation for students to learn Filipino and English easily. Program implementation in public schools is being done in phases starting SY 2012–2013. Grade 1 entrants in SY 2012–2013 are the first batch to fully undergo the program, and current 1st year Junior High School students (or Grade 7) are the first to undergo the enhanced secondary education program. To facilitate the transition from the existing 10-year basic education to 12 years, DepEd is also implementing the SHS and SHS Modeling. Here are some of the reasons why not disagree with K- 12 education plan in the Philippines: If K- 12 will be implemented, students will be able to get sufficient instructional time to do subject- related tasks which makes them more prepared and well- trained on that subject area. On the other hand, if we remain on the old system, Filipino students would continually get low achievement scores. For instance, international test results revealed that we often come at the tail end in the exams compared to other countries. Another good reason why we should support K- 12 is that the graduates of this program will be more prepared to enter the labor force. As we all noticed, high school graduates of the current curriculum are not yet employable for the reason that they are not yet competent and well – equipped with the skills needed in the workplaces. In addition, most high school graduates are not yet reaching the legal age of 18. With the new curriculum, senior high school students can choose a field that they are good at and that they are interested in. As a result, they will be equipped with the skills needed for a specific job even without a college degree. At the age of 18, the age when they graduate from high school, they will be employable and competitive already. Thus, adding up to the nation’s manpower. Finally, with K- 12, Filipino graduates will be automatically recognized as professionals abroad because we are following the international education standard as practiced by all nations. There will be no need to study again and spend more money in order to qualify to their standards. With this, Filipino professionals who aspire to work abroad will not find a hard time in getting jobs in line with their chosen field and will be able to help their families more in the Philippines as well as the country’s economy with their remittances, property buying, and creation of businesses. Filipinos are known to be competitive in the international community. While this may be true, our current education system hinders us in becoming more competitive among other countries. The K- 12 education plan offers a great solution to that problem. However, it is undeniable that there seems to be problems arising as we implement the program such as lack of government budget, classrooms and school supplies as well as the teachers. But, if we focus on the long- term effect of K- 12, we can conclude that it is very beneficial to us Filipinos. Therefore, we must have the strong will in supporting K- 12 Educational Plan for the betterment of our education system and economy. Remember, if we want change in our society, we must start it with our education system.

How I Learned From The Class Writings - 1418 Words

As I look back to when I first started taking this class I began to think about the things that I have learned. It had been quite a long time since I wrote anything other than basic notes or letters before I started taking the EN100 course. In fact, I have never been much of a writer even when writing about subjects I enjoy, so when the Justice was brought up as the main topic of the papers that we would be writing over the semester I was less then pleased. Now that my misgivings as a writer and my distain for the overall subject matter are out in the open, let’s get back to the subject at hand. What have I learned in EN100 or more specifically, what have I learned from each of the papers I wrote on justice and from the in class writings?†¦show more content†¦Another thing I learned from that first paper is that it is not acceptable to forsake the freedoms of some in order to better the majority. John Rawls, wrote in his book, ‘A Theory of Justice that Each per son possesses an inviolability founded on justice that even the welfare of society as a whole cannot override. For this reason justice denies that the loss of freedoms for some is made right by the greater good shared by others. So not only should justice be upheld for all people, regardless of their situation, but that these rights should not be overlooked in order to merely appease a majority. My second paper entitled Unjust American Justice showcased an article by Talia Jane called â€Å"5 ways America’s Justice System Is Designed to Screw You.† I learned from writing this paper is that someone cannot simply use â€Å"facts† that are based on a single persons experience if that person does not allow people to check their facts by withholding the name of their source. When writing one should always try to state facts, not opinion or bias experience. 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