Microbiology lab Practical Exam 1 Questions & Answers With Complete Solution

Hospital-aquired infection (often due to a lack of proper aseptic techniques) - Answer Nosocomial Sterile; free from contamination - Answer Aseptic Approximately 2 million - Answer How many people acquire an infection as a result of hospitalization every year? 4th - Answer Nosocomial infections are the _____ leading cause of death in the US today. Demonstrated how effective hand-washing could be, drastically reducing infections in his own patients in 1840 - Answer Ignaz Semmelweis -Developed for training in situations requiring effective hand washing, such as medical care facilities, restaurants, etc. -Invisible to the naked eye in regular light but will glow bright white under UV light - Answer Glo-Germ Bottom - Answer All identification marking go on the ________ surface of the agar plate! The number of germs necessary to initiate infection; varies from one type of microbe to another - Answer Infectious dose FALSE - Answer T/F: Handwashing is unimportant if sterile gloves are used. 20 seconds - Answer What is the accepted health care standard length of time for hand washing? Hand washing reduces the number of microbes on the hands so the infectious dose is no longer present; doesn't actually lower the infectious dose itself but lowers the number of microbes so that hopefully the infectious dose is no longer present - Answer How does the infectious dose relate to hand washing? Before and after contact with every patient - Answer As a healthcare professional, when should you wash your hands? Tops of thumbs, in between fingers, and at fingertips - Answer Which 3 areas of the hands are most often missed while hand washing? During incubation, any bacterium on the alarm divides and forms a colony; the more on the agar, the more that was on your hands - Answer How can touching a sterile agar plate before and after hand washing indicate how well you removed bacteria from your skin? 37 degrees Celsius - Answer In Celsius, what is human body temperature? 25 degrees Celsius - Answer What is room temperature in degrees Celsius? To show the effectiveness of washing hands and washing them long enough - Answer What was the purpose of the Glo-Germ gel in lab 1? To show that even shaking someone's hand can transfer germs; if you do not wash your hands before putting on sterile gloves, the germs can also transfer to the outer surface of the gloves - Answer What was the purpose of the Glo-Germ power in lab 1? The study of microbes that are too small to be seen well with the unaided eye (viruses, bacteria, fungi, & protists such as protozoans, slime molds, and algae) - Answer Microbiology Compound light microscope, stereoscopic/dissecting microscope, and electron microscope - Answer What are 3 different types of microscopes? Compound light microscope and stereoscopic/dissecting microscope - Answer Which 2 types of microscopes use light to illuminate the specimen? Electron microscope - Answer Which type of microscope uses a beam of electrons to form an image of the specimen? The two light microscopes (compound light microscope and stereoscopic/dissecting microscope) - Answer In lab 2, which 2 types of microscopes will be studied? With two hands, close to the body, in an upright position, one hand under the base to support it from the bottom and the other hand around the arm; set it down on a paper towel so that you can move it around on the table without jarring it - Answer How do you properly carry a microscope? -Provides support and helps stabilize the microscope -Contains a light source called the substage lights -Contains the power cord and switch on the back of the base that turns the light on/off - Answer Base Located on the base; provides the light that illuminates the specimen - Answer Substage light Supports the body tube and the adjustment knobs - Answer Arm The flat, black platform where the microscope slide is placed for viewing - Answer Stage -Contains a spring loaded slide holder that anchors the slide in place for viewing -Also contains 2 slide movement knobs that allow the secured slide to be moved left, right, forward and back - Answer Mechanical Stage Apparatus -Located just under the stage -Compresses the light into a tight beam before it enters the specimen -The thick silver level right under the front of the stage raises and lowers the condenser; we use the condenser all the way up - Answer Condenser -Controls the size of the opening in the iris diaphragm; the amount of light passing through the specimen can be a critical factor -Thin, black lever below the condenser -At higher magnifications, more light is needed - Answer Iris diaphragm -Attached to the upper end of the arm -Contains mirrors that reflect light coming from the lenses up to the eyes -The eyepiece (which contains the ocular lens) is located at the top of the body tube; the revolving nosepiece with the 4 objective lenses is located below the body tube - Answer Body tube -The ocular lens has a magnification of 10x -May be turned backwards or forwards by loosening the eyepiece anchor screw -Compound light microscopes are monocular (1 eyepiece containing the ocular lens at the top of the body tube) and stereoscope/dissecting microscopes are binocular - Answer Eyepiece with ocular lens -Revolving nosepiece is at the lower end of the body tube and attached are 4 objective lenses: scanning objective, low power objective, high power objective and oil immersion objective - Answer Revolving nosepiece with objective lenses Shortest objective, red band, 4x magnification - Answer Scanning objective Yellow band, 10x magnification - Answer Low power objective Blue band, 40x magnification - Answer High power objective Longest objective, white band, 100x magnification - Answer Oil immersion objective Multiply the magnification of the ocular lens (10x) by the objective lens being used - Answer Total magnification -Adjust the distance between the objective lens and the specimen being observed -The larger, inner knobs are the course adjustment knobs: move stage up/down and should only be used with scanning and low power objectives -The outer, smaller knobs are the fine adjustment knobs: fine-tune the focus and can judge depth of the specimen; safe to use with any objective - Answer Focal adjustment knobs Used to clean the lenses of the microscope (ocular lens, condenser glass, high power objective lens and oil immersion lens last) - Answer Lens paper Look through the eyepiece with your dominant eye and leave the other eye open so you won't develop eye strain from extended periods of microscope use - Answer How to look into a microscope The entire circular area that you see through the eyepiece - Answer Field of view What these two microscopes are; the specimen is in focus with one objective lens and will remain in focus with other objective lenses (only fine adjustment knob is necessary when going from one objective lens to another) - Answer Parfocal