Microbiology Lab Exam 1- Biol 2120 with correct answers 100% 2026

Microbiology Lab Exam 1- Biol 2120 with correct answers 100% 2026 What was the purpose of this microscope laboratory experiment? - Correct Answer to name the parts of a compound light microscope and their functions, learn the correct way to use the c.l.m what is the difference between magnification and resolution? - Correct Answer magnification: uses special lenses to enlarge image of an object. resolution: separates or distinguishes structures to close together what is the purpose of placing immersion oil on the slide? - Correct Answer prevents scattering of light what are the advantages of electron microscope as compared to light microscopes? - Correct Answer electron microscopes: uses electron beam light microscope: uses lights to visualize object two major differences between prokaryotic cells & eukaryotic cells - Correct Answer prokaryotic cells: single celled & no nucleus eukaryotic cells: membrane bound nucleus & DNA if the ocular magnification is 40x and the oil immersion objective is in place, what is the total magnification? - Correct Answer 40X x 100= 4000X what is simple staining? - Correct Answer when one stain is used to examine shape and arrangement of bacteria what is the purpose of the smear prep lab experiment? - Correct Answer 1. to prepare a bacterial smear 2. study bacterial morphology why should one make sure that the commercially available glass slide does not have a layer of grease before preparing the smear? - Correct Answer 1. To get an even stain 2. Because the stain and smear will not stay what would happen if you had skipped the heat fixing step and continued with the staining procedure? - Correct Answer the bacterial cells on the slide would shift when the agents are being rinsed off which would mean the bacteria would go down the drain. what is the reason for sterilizing the whole wire and part of the handle of the inoculating loop before and after each transfer? - Correct Answer to ensure that the bacteria is free of contamination from other microorganisms. list the most common shapes and arrangements of bacteria and provide a specific example of each: - Correct Answer cocci: oval/round: streptococcus pneumonae bacilli: rod shaped: bacillus anthrasis spirillum: spiral with one or more twists why is knowing the bacterial shapes and arrangement important? - Correct Answer enables scientists to determine what type of bacteria it is and what methods need to be used to control growth what is the purpose of negative staining - Correct Answer to identification of certain bacteria or structures that are normally difficult to stain why is the technique called "negative staining" - Correct Answer the bacteria is not stained but the the background is. the bacteria appears clear while the background looks dark why does nigrosin not stain bacterial cells/structures? - Correct Answer nigrosin is negatively charged and are repelled by bacteria that have the same negative charge. give 2 situations where the negative staining procedure would be used. - Correct Answer 1. used to accentuate capsules that surround certain bacteria/yeasts 2. used to determine if known bacterial infections are either gram+ or gram- bacteria due to the composition of the cell wall. what is the purpose of the streak plate method? - Correct Answer isolate pure colonies of bacteria