Rasmussen WebEx Enterprise Site - Replay Recorded Meeting

Assignment 1 -  Pigments in Photosynthesis Purpose This discussion activity will expand upon your knowledge and understanding of pigments used in photosynthesis. Specifically you will be discussing an important and annual phenomenon in this area: the rich colors of fall leaves. Directions: Please refer to the discussion guidelines Download the discussion guidelines [PDF]to understand how you should participate in the discussions throughout the course. Initial Response Read this PBS article discussing why leaves change colors. After reading this article and using other resources as needed, prepare and post the following: A brief summary of why leaves change colors in the fall, relating specifically to solar energy and photosynthesis. A more detailed discussion of 1 pigment related to fall colors. Be sure to include the pigment's name, chemical formula, and what wavelengths of solar energy it absorbs/reflects. Your references You should read as many of the other students' posts as time permits since you may get a better understanding of photosynthesis and pigments in the process. You should also then write a response to at least two other students. In your response be sure to address the description of photosynthesis and the chosen pigment. Ask any clarifying questions to expand upon your understanding. Submission Post your initial response by clicking the Reply button below, and then participate in the discussion. You can find the discussion forum by clicking the Discussions link in Course Navigation as well. Grading: Required, 20 points (15 points for your initial post, 5 points for your responses). Please refer to the discussion grading rubric attached to this forum to understand how the discussion will be graded. Assignment 2  Ethics and Biotechnology  Purpose This discussion activity will expand upon your knowledge and understanding of biotechnology as it relates to genetics, and some of the ethical issues surrounding this topic. Specifically you will be discussing whether doctors and scientists should be allowed to evaluate infants' DNA for a multitude of diseases and disorders that could arise during the baby's lifetime. Initial Response Read the article, Children to Order: The Ethics of 'Designer Babies' discussing ethical concerns surrounding genetic testing in infants. After reading this article and using other resources as needed, prepare and post the following: A brief summary of the ethical concerns surrounding this topic. Your own well-supported personal viewpoint on this issue and how you would defend your viewpoint to a person who disagrees with you. Your references. Discussion Participation You should read as many of the other students' posts as time permits since you may get a better understanding of the ethics surrounding genetic testing in biotechnology. You should also then write a response to at least two other students. In your response be sure to address your concerns and any key issues that are raised. Ask any clarifying questions to expand upon your understanding. Assignment 3 One Species At A Time Purpose The discussion forum will introduce you to the great variety of organisms on earth. Initial Response Please click on "One Species At A Time Podcast." Pick and listen to a podcast of a topic of your interest. Each podcast will last about 5 minutes and you can download the transcript. Please look up more information about the main organism discussed in the podcast and write a report about the organism. Include the scientific name(s) of the organism(s). If there are more than one organism described, please choose only one, but summarize the podcast briefly. Your primary report should address the following points: Brief summary of podcast POST Hi, how are doing?.  could you please respond to this.  thank youResponse 1 Asmaa Why do leaves change color?I. summaryOne must understand the concepts of tree pigments and photosynthesis to comprehend why leaves change color.  Chloroplasts are the main location of photosynthesis, where light is captured and transforms carbon dioxide and water into oxygen and sugars.  The sugars force a chemical reaction and the growing function in plants and trees.  Chlorophyll, as a vital pigment, absorbs sunlight and is responsible for the green color in leaves.  But chlorophyll requires sunlight and warmth to thrive and thus in the fall season, it is broken down and instead other pigments—carotene and xanthophylls—become dominant due to chlorophyll’s weakness during this time, and they bring about the yellow and orange colors in the Fall leaves.  Reds and purples come from the pigment anthocyanins in certain trees like scarlet maples and dogwoods.  The quality of color of the leaves is based on optimal sun and ground temperatures, and on mild wind conditions so that the leaves can stay intact on the trees.  Studies in Europe and Japan suggest that warmer temperatures are responsible for early spring flowering and holding their leaves until late in Autumn.   Warmer temperatures are a concern especially in summer if trees get too hot and don’t survive into the fall.  II. Chlorophyll pigment Photosynthesis (6CO2+6H2O?C6H12O6+6O2) is a process in which the sun’s energy is converted into a chemical energy (six carbon dioxide molecules and six water molecules are transformed by the chlorophyll into sugar molecule and six oxygen molecules). This organism contains light observing molecules called pigments. One of the main pigments found in plants is chlorophyll.  Based on “Khan Academy,” these pigments absorb light in different wavelengths.  Based on “Khan Academy” chlorophyll absorb these wavelengths efficiently at about 450 nm and 650 nm.The resource below offered a detailed diagram about these wavelengths. Response 2 Jordan RodriguezThe change of color in the leaves occurs during the transition from summer into fall. This color change is due to the breakdown of Chlorophyll, the compound that gives leaves its green color, that requires sunlight and warm temperatures. But during fall the temperatures begin to drop and night grow longer and sunlight hours decrease. When the Chlorophyll is being broken down Carotenoids, and xanthophyll are unmasked and change the color of the leaves from green to yellow and orange. Other pigments that are seen throughout the transition of leaves changing color are anthocyanins, giving leaves their purple and red colors. In respects to photosynthesis, leaves have chloroplast, the site in which photosynthesis takes place. As photosynthesis slows down the production of Chlorophyll decreases. This overall decrease in Chlorophyll is what allows the other pigments to show through and change the color of the leaves.  In summary, the color change in leaves is dependent on weather, sunlight and soil moisture.Anthocyanins is a pigment that is related to fall colors and plays an effect in the change of colors in leaves during the fall. Anthocyanins absorb blue, blue-green and green light therefore, the light reflected by the leaves appear to be red and purple-ish to the eye. While Chlorophyll and other pigments found in leaves are attached to the cell membranes, anthocyanins are dissolved in the cell sap. The brightness of the color that appears on the leaf is dependent on the pH level of the sap. The more acidic the sap is then the brighter the pigment of red and if the sap is less acidic then the color appears more purple. This pigment is not only responsible for the color in leaves but also responsible for the red skin of ripe apples and grapes. It can also explain why apples often appear more red on one side and green on the other, because of anthocyanins.Chemical Formula:C15H11O+Wavelengths of Solar Energy:It absorbs mainly green photons but as well as blue and greenish-blue lights.It reflects red and purple wavelengths, giving the leave its red and purple colors.