Micro lab quiz Essay Example

Micro lab quiz Essay Example Micro lab quiz Paper Micro lab quiz Paper The Gram Stain Compare and contrast simple and differential stalling techniques. Simple Stalling Simple stalling Is useful In determining the basic morphology of an organism. Simple stalling Involves only one reagent I. E. Crystal violet, basic fuchsia, or methyl blue. Simple dyes used to stain bacteria have a positive charge cationic (+), therefore, they are attracted to the bacteria that are usually negatively charged anionic (-) Depends on the fact that bacteria differ chemically from their surroundings and thus can be attained with their environments Simple stains are used to provide contrast between specimen and background Differential Staining Bacteria react differently to the multiple reagents that are used I. E. Gram Stain = Crystal violet, Grams Iodine, 95% ethyl alcohol, and sassafras. I. E. Acid-fast stain Can distinguish between 2 types of bacteria because bacteria differ from one another chemically and physically to react differently to a given staining procedure. State the purpose of the Gram stain. The Gram stain separates bacteria Into two major groups: Gram positives that stain rupee, and Gram negatives that stain pink or red. Primary Stain Crystal violet; Mordant = Grams Iodine; Decolonize = 95% ethyl alcohol; Countersink = Seafaring. Perform and interpret a Gram stain. Gram positive = stains purple Gram negative = stains pink or red Discuss the consequences of deviations from proper Gram staining technique. If there is deviation from gram staining, gram positive bacteria may stain and look like they are gram negative, or vice versa. Exercise 10 Miscellaneous Staining State the purpose of the acid-fast, endoscope, and capsule stains. Acid-Fast Stain Another example of a differential stain. Seed to diagnose diseases like Tuberculosis. Stains mycobacterium which cause tuberculosis Mycobacterium contains mycology acid (waxy substance) in the cell wall and it makes the organism very slow-growing and thus difficult to isolate and identify. Endoscope Stain Stain bacteria with endoscopes such as Colostomies and Bacillus. Because of their nearly impenetrable cell walls, the Gram-stain method will not stain endoscopes; therefore, this specialized staining method Is necessary. Schaeffer-Fulton Method uses malachite green stain with heat and sassafras for a countersink. The endoscope ill stain green and the surrounding vegetative cell will stain pink. Capsule Stains (Negative Stain) To identify bacteria with capsules, since capsules do not stain with simple staining or gram-stalling one moment uses engrossing (or IANAL Ink), wanly stalls ten Docudrama black. Crystal violet is used as a countersink to stain the bacterial cell, thus making the capsule visible as a clear halo around the cell. Capsule = when slime layer is highly symmetrical and organized; play a role in the virulence (disease-causing ability) of some bacteria. Describe the purpose of endoscopes, and compare and entrants two common genera that produce them. Endoscopes allow bacteria to survive in extreme environmental conditions such as heat, cold, or drought. Survive extreme heat, lack of water, and many toxic chemicals and radiation due to them being highly durable, dehydrated cells with thick cell walls. Unique to certain genera of bacteria Colostomies Anaerobic Extremely pathogenic Gram positive, spore forming, bacilli (rods) Bacillus Aerobic Pathogenic but easier to get rid of than colostomies. Describe the purpose of a capsule. Capsule Gives cell its virulence factor: anything bacteria have evolved to make them more tightening Prevent phagocytes which means antibodies against the bacteria are useless and ineffective. Exercise 11 Culture Media Preparation Compare and contrast the uses of general-purpose, selective and differential media, and provide examples of each. General-purpose Media These are nonconsecutive primary isolation media used for culturing a wide variety of microorganisms. Consists of beef extract, potent, and agar. Ex: Nutrient Agar and Broth, TTS plates Selective Media Allow only certain types of bacteria to grow Usually have inhibitory substances that restrict the growth of other unwanted bacteria. Ex: Columbia (CAN) Media Differential Media Contains various substances that cause some bacteria to take on a different appearance from other species. Ex: EMBED (Eosin Methyl Blue) Calculate proportions necessary to make different amounts of culture media when given a recipe. He weight nouvelle known-?the weight wanted volume wanted Discuss the importance of sterilization in medium preparation, state the conditions under which complete sterilization occurs, and name the equipment used to achieve it. Sterilization of culture media is done to eliminate contaminating microorganisms from the environment. Complete sterilization occurs at 250 degrees Fahrenheit (121. 6 degrees Celsius) at 1 5 pounds per square inch (SSI) of steam pressure. Autoclaves provide this type of sterilization. Exercise 12 I en streak Plate Ana colony Morphology Describe the purpose and principle of the streak plate. Used to isolate bacteria colonies and helps to obtain a pure culture for further studies. The more streaks, the more the bacteria will be diluted until, in theory, only one cell is left to grow and give rise to a colony of the same bacteria. Explain why Petri plates are incubated in an inverted position. Lessens the risk of contamination of other microbes settling on them and to prevent water condensation that might compromise a culture. Describe how colonies form on a Petri plate and explain why isolation is an important procedure in microbiology. Isolation is an important procedure in microbiology because it helps to obtain a pure culture for further studies. Without a pure culture, you would not be able to tell if the bacteria was what you really wanted to look at or not Since bacteria of the same species will produce nearly identical colonies, isolation will confirm whether or not a pure culture was obtained. Exercise 13 Specimen Transport Ubiquity of Microorganisms Describe the principle and purpose of RADAR plates, and apply the guidelines for evaluating degree of surface contamination. Used for the detection and enumeration of microorganisms present on surfaces of sanitary importance. Replicate Organism Detection Counting Colonies per RADAR Plate GOOD = 0-25; FAIR = 26-50; POOR = 50 and over Describe the importance of quality control (ICQ) in microbiology in general, and the Gram stain in particular Generally: to verify a satisfactory level of freedom from contamination, To demonstrate the erect performance of the medium when used in the usual or widely accepted manner, Ensure against significant physical imperfections that may compromise the utility of the media. Gram Stain To be sure that you stained the organism correctly Also, to make sure that the stains are working the way they should e: gram-positives come out purple, and gram-negatives come out pink Important when trying to identify unknowns Exercise 14 Hand-Washing State the importance of hand washing before and after microbiological procedures, including the use of disinfectant when scrubbing for a medical procedure. Washing our hands before microbiological procedures is important because you decrease the chance of contaminating any cultures you work with. After microbiological procedures, you probably have a lot of contaminants (transient bacteria) on your hands that can make you sick. Washing your hands kills some of these and decreases your chance of becoming sick afterwards. Using disinfectant when scrubbing for a medical procedure is important so that you provide a sterile environment for the procedure so that you do not cause an infection in a patient. Define the terms monoclonal, contaminant, transient and resident as they apply to agrarianism. Monoclonal Intentions = Intentions Tanat are spread In a nonstop environment Patient did not have the infection before she came into the hospital; newly acquired from the hospital. Transient Bacteria = Contaminants that are not part of the normal human flora; may be present for a finite time. Resident Bacteria = Permanent residents of normal human flora Contaminants = Bacteria that you do not want present in a culture medium; Also, bacteria that are not part of the normal flora. Exercise 15 Bacterial Plate Counts Use the plate count technique to calculate bacterial density in a sample. Serial dilutions? Perform serial dilutions using serological and digital pipettes. Perform dilution problems [FINAL (SCUFFS/NIL)] = COLONY FORMING UNITS (SCUFFS) / VENUE PLATED (ml) [ORIGINAL (SCUFFS/ml)] = [FINAL] / DILUTION FACTOR Define the terms COIF, aliquot, diluted, dilution factor, TNT, and TFTP. COIF = colony forming unit Number of colonies that you count Must be between 30-300 colonies Aliquot = Smaller volume withdrawn from a total sample volume. Diluted = Fluid used to dilute a sample. Dilution factor = Fraction by which original sample concentration is diluted. TNT -? Too Numerous To Count = Colony count is greater than 300 TFTP = Too Few To Count Colony count is less than 30 Explain the convention of only counting plates that have between 30 and 300 colonies. Counts over 300 colonies are considered invalid because of overcrowding that may cause two or more bacteria to form a single colony; also, they are too tedious to count accurately. Counts under 30 colonies are invalid because there may have been a sampling error. Exercise 16 Bacterial Growth Characteristics A: Osmotic Pressure Describe osmotic pressure and how it affects a cell. Osmotic pressure is the pressure that water exerts on a cell from either leaving the ell (hypersonic conditions) or entering the cell (hypotonic conditions) The force that is exerted to maintain the concentration differences between solutions on opposite sides of the membrane. Hypersonic Conditions = water moves out of the cell causing it to create or shrink Hypotonic conditions = water moves into the cell causing the cell to else or explode Isotonic conditions = No net water movement, no osmotic pressure. Most bacteria exist at hypotonic solutions Some can exist in hypersonic solutions = wholesale. B: Oxygen Describe and recognize facultative anaerobe, strict robe, retaliation anaerobe, obligate anaerobe. Facultative anaerobes They can grow with or without oxygen, but grow better with oxygen because they can utilize It! In ethnologically meal, It wall owe Tuna more towards ten top (oxygen) can still be seen throughout the tube. Strict robe Cannot survive without oxygen. Found at top of technologically where oxygen is. Retaliation anaerobe Cannot utilize oxygen to grow, but can tolerate it. Found throughout the tube, but gathers more at the bottom where there is less oxygen. Obligate (Strict) Anaerobe Cannot exist in presence of oxygen Oxygen is toxic to them. Found at very bottom of technologically tube. Microelectronic bacteria Grow best when the atmosphere has increased CA (carbon dioxide) and lower concentrations of oxygen are present. Found near middle of technologically tube. Know the parts of the anaerobe Jar and how it works.