Microbiology Lab test 1 – 6 Complete Solutions 100% Verified Answers Graded A+.

Base - correct answers Supports the microscope. It is important that when carrying the microscope you have one hand under the base and one wrapped around the arm. Arm - correct answers is important for carrying the microscope. Stage (mechanical stage) - correct answers platform that holds the microscope slide and slide holder . This platform function is to hold an object for viewing. Slide holder - correct answers is the spring loaded clamp and its job is to hold a microscope slide firmly on the mechanical stage. Forward/backward & Lateral motion knobs - correct answers for moving the slide with the specimen. Substage lamp - correct answers provides light for viewing the specimen , uses iris diaphragm lever to further adjust light condenser focus knob - correct answers moves the condenser up or down to control the lighting focus on specimen condenser unit - correct answers the lens of the condenser and the control of the amount of light that passes through the condenser lens condenser - correct answers lens that condenses the light before it passes through the specimen iris diaphragm - correct answers controls the amount of light that passes through the condenser lens ocular lenses - correct answers magnify specimen by a factor of 10. total magnification will be 100x for low power, 400x for high power and 1000x for oil immersion diopter ring - correct answers used for adjusting the focus to the users eyes width adjustment - correct answers adjusts distance between ocular lenses to match the distance between eyes of viewer Revolving nosepiece - correct answers for rotating the objectives into viewing position objective lenses - correct answers4x, 10x, 40x, 100x lens that magnify the specimen scanning lens - correct answers4X the objective used to see the greatest field of view at the lowest magnification. To use for the initial search over a wide area. Lowest objections have the shortest tubes Low power 10x - correct answers The low power objective lens helps to first fine the specimen or object being viewed, and to focus the microscope high power 40X - correct answers intermediate sized objective , the objective is used for higher magnification without oil Oil Immersion 100x - correct answers the objective used for the highest magnification with oil Coarse adjustment (coarse focus knobs) - correct answers bigger knob for focusing the specimen ( only use for 4x & 10x objectives) Fine adjustment (fine focusing knob) - correct answers smaller knob located on coarse knob for focusing specimen - able to use with all objectives Function of immersion oil - correct answers help increases the resolution of a microscope . This keeps the light from bending. Oil - 100x - correct answers only lens that can tough immersion oil What would occur if water were accidentally used in place of immersion oil? - correct answers You would have the refractive index the bending of light passing through air between the objective , water and lens. The density is lower if you use water over immersion oil What effect does increased magnification have on the field of vision? - correct answers The high the magnification the smaller the field of vision Working distance - meaning working distance on low power vs high power - correct answers working distance is reduced as the magnification increases. Working distance is the free area available that allows you to work or manipulate the sample. You have more working distance on the scanning lens and the least on the oil immersion lens. Which focus know to use : scanning lens - correct answers coarse knob until object is in focus then the fine knob to focus which focus knob to use : low power - correct answers fine knob only to focus which focus knob to use : high power - correct answers fine knob only to focus ( cannot move coarse knob too high, potential to break lens) which focus knob to use : oil immersion - correct answers fine knob only to focus ( cannot move coarse knob too high, potential to break lens) What are the reasons for always starting on low power? - correct answers Scanning for microbes and then working your way up on magnification , find the specimen and prevent damage to slide or specimen Resolution - correct answers the observer is still able to distinguish at the shortest distance between two parts on a specimen in a microscopes field of view What is the function of the iris diaphragm - correct answers controls the amount of light that passes through the condenser lens. Lowering the iris diaphragm is helpful in seeing the specimen in the immersion oil lens When and what is the correct way lens should be cleaned? - correct answers The oil immersion lens and they should be cleaned with lens paper What items should be checked if you have difficulty focusing microscope - correct answers ocular lens, make sure clean. Objective lenses make sure clean with lens paper if unable to see. Check lighting , may have too little / too much . start at the lowest objective an see if you can see anything and then go up higher on magnification culture medium/media - correct answers a nutrient material prepared for the growth of microorganisms in a lab inoculum - correct answers microbes that are introduced into a culture medium initiate growth culture (microbial) - correct answers microbes that grow & multiply in or on a culture medium Sterile medium - correct answers initially contains no living microorganisms - the culture will only contain the microbes ( & their offspring) we add to the medium agar - correct answers a complex polysaccharide derived from a marine alga agar liquefies at - correct answers100 deg C Agar solidifies at - correct answers40 deg C slants - correct answers test tubes agar are usually contained in - their contents are allowed to solidify with the tube held at an angle that a large surface area for growth is available deeps - correct answers when the agar solidifies in a vertical tube petri dishes - correct answers names for the inventor, shallow dishes with a lid that nests over the bottom to prevent contamination petri plates - correct answers when petri dishes are filled chemically defined media - correct answers one whose exact chemical composition is known usually reserved for lab experimental work or for growth of autotrophic bacteria fastidious organisms - correct answers organisms that require many growth factors. i.e. Lactobacillus - used to test that a concentration of a particular vitamin is in a substance complex media - correct answers made up of nutrients including extracts from yeasts , meat or plants , or digests of proteins from these and other sources nutrient broth - correct answers complex media in liquid form nutrient agar - correct answers when agar is added selective media - correct answers designed to suppress the growth of unwanted bacteria and encourage the growth of desired microbes differential media - correct answers make it easier to distinguish colonies of the desired organism from other colonies growing on the same plate enrichment media - correct answers usually liquid and provides nutrients and environmental conditions that favor the growth of a particular microbe but not others