Battle of Shiloh essays

Battle of Shiloh essays During the night of the April 5, 1862, Confederate commander, Albert S. Johnston, was sound asleep. Throughout his life he had reoccurring dreams in which a unicorn, with the name Shiloh, would appear and foretell what was to transpire within the next twenty-four hours. The unicorn stood tall and majestic with hair snow white and a horn of golden color that shimmered when light touched it. Its eyes were that of one which had seen much and obtained knowledge others couldnt even claim to possess. That night the unicorn appeared in his dreams and enlightened him with such information. It told of what was to take place when he arrived at the Union encampment at Pittsburg Landing, of the Battle that would go on to be called Shiloh, named after a meetinghouse 3 miles from the Landing. Then the unicorn spoke of his death. This was to be the last battle fought by Johnston, and his death was described to him in vivid detail. He woke up in a cold sweat, knowing that what the unicorn had said should be taken seriously because all it speaks of is truth. By that time, the first signs of morning were beginning to take place. The world was starting to wake up. Johnston and his troops headed towards the Union encampment, and upon their arrival they achieved complete surprise which was what the Confederates had anticipated. Due to the fact that neither side had ever fought in a battle in their lives, there was mass confusion. The Rebels were defeating the Federals position one after another, but the Union commander, Ulysses S. Grant , ordered for his troops to block the sunken road, in which the Confederates were traveling on, no matter what. Shots were fired at the Federals, but it did not faze them, at least not until the Confederate army obtained sixty-two cannons and started firing them at point black range down the sunken road. Soon after that monstrosity, the Union troops were forced to surrender. ...

Photosynthesis Study Guide - Key Concepts

Photosynthesis Study Guide - Key Concepts Learn about photosynthesis step-by-step with this quick study guide. Start with the basics: Quick Review of the Key Concepts of Photosynthesis In plants, photosynthesis is used to convert light energy from sunlight into chemical energy (glucose). Carbon dioxide, water, and light are used to make glucose and oxygen.Photosynthesis is not a single chemical reaction, but rather a set of chemical reactions. The overall reaction is:6CO2 6H2O light → C6H12O6 6O2The reactions of photosynthesis can be categorized as light-dependent reactions and dark reactions.Chlorophyll is a key molecule for photosynthesis, though other cartenoid pigments also participate. There are four (4) types of chlorophyll: a, b, c, and d. Although we normally think of plants as having chlorophyll and performing photosynthesis, many microorganisms use this molecule, including some prokaryotic cells. In plants, chlorophyll is found in a special structure, which is called a chloroplast.The reactions for photosynthesis take place in different areas of the chloroplast. The chloroplast has three membranes (inner, outer, thylakoid) and is divided into th ree compartments (stroma, thylakoid space, inter-membrane space). Dark reactions occur in the stroma. Light reactions occur the thylakoid membranes. There is more than one form of photosynthesis. In addition, other organisms convert energy into food using non-photosynthetic reactions (e.g. lithotroph and methanogen bacteria)Products of Photosynthesis Steps of Photosynthesis Here is a summary of the steps  used by plants and other organisms to use solar energy to make chemical energy: In plants, photosynthesis usually occurs in the leaves. This is where plants can get the raw materials for photosynthesis all in one convenient location. Carbon dioxide and oxygen enter/exit the leaves through pores called stomata. Water is delivered to the leaves from the roots through a vascular system. The chlorophyll  in the chloroplasts inside leaf cells  absorbs sunlight.The process of photosynthesis  is divided into two main parts: light dependent reactions and light independent or dark reactions. The light dependent reaction happens when  solar energy  is captured to make a molecule called ATP (adenosine triphosphate). The dark reaction happens when the ATP is used to make glucose (the Calvin Cycle).Chlorophyll and other carotenoids form what are called antenna complexes. Antenna complexes transfer light energy to one of two types of photochemical reaction centers: P700, which is part of Photosystem I, or P680, which is part of Photosystem II. The photochemical reac tion centers are located on the thylakoid membrane of the chloroplast. Excited electrons are transferred to electron acceptors, leaving the reaction center in an oxidized state. The light-independent reactions produce carbohydrates by using ATP and NADPH that was formed from the light-dependent reactions. Photosynthesis Light Reactions Not all wavelengths of light are absorbed during photosynthesis. Green, the color of most plants, is actually the color that is reflected. The light that is absorbed splits water into hydrogen and oxygen: H2O light energy →  ½ O2   2H   2 electrons Excited electrons from Photosystem I can use an electron transport chain to reduce oxidized P700. This sets up a proton gradient, which can generate ATP. The end result of this looping electron flow, called cyclic phosphorylation, is the generation of ATP and P700.Excited electrons from Photosystem I could flow down a different electron transport chain to produce NADPH, which is used to synthesize carbohydratyes. This is a noncyclic pathway in which P700  is reduced by an exicted electron from Photosystem II.An excited electron from Photosystem II flows down an electron transport chain from excited P680  to the oxidized form of P700, creating a proton gradient between the stroma and thylakoids that generates ATP. The net result of this reaction is called noncyclic photophosphorylation.Water contributes the electron that is needed to regenerate the reduced P680. The reduction of each molecule of NADP  to NADPH uses  two electrons  and requires  four photons.  Two molecul es  of ATP are formed. Photosynthesis Dark Reactions Dark reactions dont require light, but they arent inhibited by it, either. For most plants, the dark reactions take place during daytime. The dark reaction occurs in the stroma of the chloroplast. This reaction is called carbon fixation or the  Calvin cycle. In this reaction, carbon dioxide is converted to sugar using ATP and NADPH. Carbon dioxide is combined with a 5-carbon sugar to form a 6-carbon sugar. The 6-carbon sugar is broken into two  sugar molecules, glucose and fructose, which can be used to make sucrose. The reaction requires 72 photons of light. The efficiency of photosynthesis is limited by environmental factors, including light, water, and carbon dioxide. In hot or dry weather, plants may close their stomata to conserve water. When the stomata are closed, the plants may start photorespiration. Plants called C4  plants maintain high levels of carbon dioxide inside cells that make glucose, to help avoid photorespiration. C4  plants produce carbohydrates more efficiently than normal C3  plants, provided the carbon dioxide is limiting and sufficient light is available to support the reaction. In moderate temperatures, too much of an energy burden is placed on the plants to make the C4  strategy worthwhile (named 3 and 4 because of the number of carbons in the intermediate reaction). C4  plants thrive in hot, dry climates.Study Questions Here are some questions you can ask yourself, to help you determine if you really understand the basics of how photosynthesis works. Define photosynthesis.What materials are required for photosynthesis? What is produced?Write the  overall reaction  for photosynthesis.Describe what happens during the cyclic phosphorylation of photosystem I. How does the transfer of electrons lead to the synthesis of ATP?Describe the reactions of carbon fixation or the  Calvin cycle. What enzyme catalyzes the reaction? What are the products of the reaction? Do you feel ready to test yourself? Take the  photosynthesis quiz!