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Political Positions Essay, Research Paper

Phototaxis in Euglena Gracilis

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Abstraction: The unicellular flagetta Euglena gracilis ( E. gracilis ) shows positive phototaxis. We studied E. gracilis to see its effects of photosynthesis under the compound microscope. What I came up with is that E. gracilis uses photosynthesis to do their nutrient and to hold a positive phototaxis. While under the microscope, we studied the figure of E. gracilis that went from visible radiation to shaded countries. Our consequences were that the. E. gracilis has a positive phototaxis.

Introduction: In this experiment we tested the reaction of E. gracilis to visible radiation ( phototaxis ) . What is E. gracilis? E. gracilis is in the Kingdom Protista, Phylum Mastiogophora, Class Flagelleta, Order Euglenophyta, and Class Euglenoids. Euglenoids are unicellular beings whose categorization as workss or animate beings can be debated every bit either manner ( Euglenophyta, 1 ) . They have similar features of both workss and animate beings. They are non related to any algae, but because they occupy the same sorts of home grounds as algae and are of comparable simpleness ( Euglenophyta, 1 ) .

E. gracilis lives in Marine and fresh Waterss. Their pigment is green ; a few are colorless- chl a+b and carotenoids ( Euglenophyta, 1 ) . The most of import Euglenoid parts are the karyon, chloroplasts, scourge, cell wall, ocellus, and cell membrane ( Algae, 1 ) . They are individual celled with different beds inside the cell wall.

They move by one long scourge. Some Flagellates have many scourge, up to six or more. E. gracilis are plant-like because they have chloroplasts, but if the chloroplasts are removed or shaded from sunlight the E. gracilis will run for nutrient which makes them animal-like excessively ( Euglena, 1 ) . Euglena are photosensitive and are a valuable nutrient beginning for fish and other aquatic animate beings ( Euglenophyta, 1 ) .

E. gracilis rely on photosynthesis to last. They need photosynthesis to bring forth their nutrient. One would anticipate a positive phototaxis. Phototaxis is the inclination to travel toward visible radiation. The intent of analyzing E. gracilis is to see how they react with visible radiation. How long would they be attracted to visible radiation or how long would it take for them to go negatively phototaxed. Therefore, we can find that E. gracilis uses photosynthesis to do their nutrient and have a positive phototaxis.

Materials and Methods: The first measure is to take a clean glass slide and usage Vaseline to sketch a little square on the slide. Then topographic point a few E. gracilis beads on the slide, in the square. Make s

ure to non set excessively much of the substance on the slide or they will overrun the Vaseline. Put a clean screen faux pas over the square of Vaseline. Make certain that there are no air bubbles trapped between the E. gracilis and the screen faux pas. Take a piece of black paper and cover half of the slide with it. Check to see if the paper covers the underside of the slide every bit good. Put the slide under a compound microscope so that half of the slide is in the visible radiation and the other half contains the black paper. When utilizing the microscope, be certain to utilize the lowest power at first. Excessively much visible radiation could kill the life signifiers. Carefully concentrate until you are able to see the E. gracilis clearly. Accurately count the figure of swimming E. gracilis in the field of position every two proceedingss for 10 proceedingss entire. Properly record the informations on graphs and tabular arraies. Next you must execute a control experiment. In the control experiment you will execute the same experiment as before with one exclusion. The exclusion is that the black paper will non be used. It is of import to maintain as many of the other factors every bit changeless as possible ( temperature, figure of beings, clip intervals, field of position counted, etc. ) ( Jacklet, 20 ) .

Consequences: We found what one would anticipate to happen when covering with phototaxis in E. gracilis. The control figure of E. gracilis fell because the visible radiation was excessively strong and it would kill the beings. The experimental figure of E. gracilis went down because the being was smart plenty to acquire out of the visible radiation. For every two-minute interval we can see the figure of E. gracilis lessening. See affiliated tabular arraies.

Discussion: The consequences were reasonably similar through both experiments. As you can see, the Numberss went down with each interval alteration. There is an mistake in the control experiment due to the strength of visible radiation. We see that some E. gracilis disappeared. They died due to over-phototaxis ( excessively much light ) . This proves my hypothesis that E. gracilis use photosynthesis to do their nutrient and have a positive phototaxis.

Mentions:

Algae Classification. ( 10/22/99 ) p. 1. hypertext transfer protocol: //www.kent.wednet.edu/staff/rlynch/sci_class/chap09/lesson_protista/Protista_Lesson.html

Euglena. ( 10/22/99 ) p. 1

hypertext transfer protocol: //www.biosci.ohio-state-edu/ zoology/eeob405/lab_1_euglena.html

Euglenophyta: the euglena. ( 10/22/99 ) p. 1

hypertext transfer protocol: //www, wmc.car.md.us/HTMLpages/Academics/Biology/botanyweb/algaeh /euglena

Jacklet, Alice. Probes in Modern Biology. 7th erectile dysfunction. Englewood: Morton

Publishing Co. , 1996.