bio 210 study guide

8/8/2019 Bio 210 Study Guide

http://slidepdf.com/reader/full/bio-210-study-guide 1/25



ProceduresDifferent tools, reagents, and types of mediaused

The theory behind the experimentBe able to identify different resultsBe able to explain the results (both wrong and

right)Be able to identify mistakes



Safety is usually fair game on quizzes and testsin most science classes; as are the lab rulesSafety rules are there for you

ShoesHair

Lab rules are there to make sure you have aproper lab to attend.Not being safe and not following rules can leadto a cut in participation points.



Mainly for you to learn how to use a microscopeproperly

Essential skill for microbiology. You must know howto use a microscopeUse proper procedures before, during, and aftermicroscope use

Still may be tested on the microscope

Parts, magnification.



Will benefit you for the rest of the semester.If you do it well, your results will turn outUnknown project



Key to remember is that microorganisms areEVERYWHEREPay attention to morphology or it will haunt youduring your unknown.



Know why the stain worksInside of cell is transparent and negatively chargedBasic stains are positively charged (chromogen)

Part that gives color is chromophorePart that has a charge is auxochrome

Opposites attract



Heat-fixingPros: kills the cell; adheres cell to slide; coagulatescytoplasmic protiens to make the more visibleCons: distorts the cells; some organisms are too delicate towithstand heat-fixing

Know types of basic dyesEG: methylene blue, safranin, crystal violetGeneral rule, if dye stains the inside of the cell, the dye isbasic

Know the basic procedures, especially the bacterial smear

Fundamental staining procedure.Also see section "Bacterial structure and Simple stains

Morphology of bacteria on a microscopic level as opposedto the macroscopic colony morphology

Shapes, how many form, how they are clustered



Another skill you willneed to use throughoutthe semester

You will have multipleattemptsUnknown project



Acidic dyeNegative chromogenEG: nigrosin, eosin

Used to identify bacteria that are too delicate towithstand heat-fixing



One of the more important differential stains inmicrobiologyHas clinical significance

StepsHeat -fixed emulsionCrystal Violet; rinse with DI waterIodine; Rinse with DI waterDecolorize with ethanol or ethanol/acetone; Rinsewith DI waterCounterstain safranin; Rinse



How does the gram stain work?Gram positive and gram negative cells havestructurally different cell walls

Gram positive: thicker, peptidoglycan layer with morecross linking from teichoic acidGram negative: thinner, more lipids



Primary stain is CVCan pass through both typesIodine acts as a mordant

Binds to CV forming crystal violet-iodine complex; essentially a largermolecule than CV alone

DecolorizationVERY IMPORTANT STEPMust do properly to get good resultsAlcohol/acetone removes lipids from cell walls; makes the wall moreporous

Gram negative: CVI washes outGram positive: CVI stays

CounterstainCVI overpowers safranin so gram positive stays purpleGram negative turns red

bio 210 study guide

Documents