(240)-343-2585

please help

please help
2420-Lab 1- Intro to Microscopy Directions: Answer following questions after reading the information and watching the video from the link below. Use color RED for your answers. Submit the completed document on eCampus for grading. Refer to Refer to the textbook Openstax Microbiology Chapter 2 Link: Microscopy Virtual Edge Experiment-1B Another optional but helpful link Intro to Light Microscopes This document has 12 questions to answer. Students MUST use scientific terminology while answering all questions For each wrong answer 0.5 points will be deducted Types of Microscopes: What are some advantages and disadvantages of light microscopes? What are some advantages and disadvantages of electron microscope? Which microscope would you use to observe the specimens below? Choose the answer from –compound light microscope or transmission electron microscope or scanning electron microscope Human cheek cell: Organelles of human cheek cell: Three dimensional shape of the cheek cell: Parts of a microscope and function of parts: Bright Field Microscope Components- Complete the following table Explain the following terms related to microscopy: Simple microscope Compound microscope Magnification Resolution Contrast Total magnification Field of View (FOV) Parfocal Parcentral Working distance Depth of field Reflection Refraction Oil immersion Orientation of specimen Care and Use of Microscopes: Watch the video from the link given at the beginning and also read the following instructions on focusing on the specimen (important- not mentioned in the video): Always start with the lowest power objective lens (4X) because this lens has the largest working distance. Keep iris diaphragm closed or to a minimum. While placing or removing the slide, have 4X objective lens in place and stage all the way down to avoid scratching the lens. Place the slide as shown in the video using a stage clip Move the stage all the way up using “coarse adjustment” Adjust oculars so that you see one field of view (circle of light) with both eyes open While observing through oculars, start moving stage down until you see the specimen Now use only “fine focus” knob to sharpen the image Once the image is sharp at 4X, you can rotate the objective to the next high level- 10X and then higher to 40X (you should not move the stage with coarse adjustment after this adjustment) When you move the objective lens from lower to higher magnification, you would have to move the X or Y axis knobs to center the image sharpen the image with fine focus (you will not need to move the coarse adjustment) light intensity needs to be increased slightly by using iris diaphragm keep in mind that as magnification increases, working distance and the diameter of the FOV decreases At this time you need not move the stage with coarse adjustment, instead you use only fine focus because image only needs sharpening The image seen through the ocular lens is upside down and reverted. See the example below: When you move the slide to right, the image moves to left and when you move the slide to left, the image moves to right. When you move the slide to front, the image moves backwards and when you move the slide to back, the image moves towards front. When you move fine focus, different parts of the specimen come into focus because all cells are three dimensional and fine focus shows that each structure within a cell is at different depth When changing objective lenses from lower to higher magnification, light intensity may be increased for better contrast since as magnification of objective lenses increases, the aperture of the lens decreases allowing less light to enter. The light intensity can be controlled by opening the iris diaphragm wider. What should you use to clean the microscopes? Which lenses should be cleaned? Which lens must cleaned last and why? Arrange all objective lenses according to the length: smallestlongest When you prepare a slide, why do you mark on one side? Why do you add on a coverslip at an angle? When you move the objective lens from lower to higher magnification, would you increase or decrease light? Why? Why is oil immersion necessary while using 100X objective lens? (Refer to the textbook)