2A: Microscopy. Post Lab 2 is assigned today and due by the time your lab meets next. Pre Lab 3 will...
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Transcript of 2A: Microscopy. Post Lab 2 is assigned today and due by the time your lab meets next. Pre Lab 3 will...
Post Lab 2 is assigned today and due by the time your lab meets next.
Pre Lab 3 will be available on Wednesday at 5 PM and is also due by the time your lab meets next.
LNA Bacteria is assigned today, and due by the time your lab meets next*.
Pre-Lab Write Up for LNA 3 is due within the first 5 minutes of lab next week.
*You will have time at the beginning of week 3 to look at your bacterial plates and complete your LNA
Develop working knowledge of a brightfield light microscope
Discern between different types of microscopy
Practice techniques: objectives, oil, wet mount, measurements
Practice with the objectives, focusing, and positioning using the prepared slides.Use your lab manual as a reference if you are
having trouble pages 29-30.
Become familiar with the scientific process by generating hypotheses, making predictions and designing experiments
Determine potential sources of microbial contamination in the laboratory
Obtain a pure culture of bacteria by streaking for isolated colonies on solid media
Prokaryotes: lack a nuclear membraneSmall, single cell organismsExist in huge numbers in small amounts of
materialFound almost everywhere
Liquid or SolidAgar
Non-toxicRemains solid at high temperaturesNot used as a nutrient
Defined or Complex
Cluster of cells visible to the naked eyeFacilitating:
Isolation of pure culturesEnumeration of cell concentration in liquid
suspensionsID of bacterial species based upon the
appearance of the colonies
A diluted suspension is pipetted directly onto the surface of an agar plate and spread across the surface using a sterile glass spreader.
The number of colonies on a plate is assumed to be equal to the number of viable cells which were spread on the plateLimiting Factors
No more than 0.2 ml of cell suspension should be spread on the plate
Resulting in 30 to 300 cells spread on the plate
The number of cells per ml is directly proportional to the mass of cells per ml
Using Spectrophotometers to measure Optical Density (OD)Light is lost as it passes through the suspension
because it is scattered and absorbed by the cells.Data can be used to construct a standard curve.
Labeling platesLabel the bottom of the agar plate Write on the periphery of the plateWrite your name, section, date, and location
Use the sterile swab to collect your contaminant and put it on the agar plate
Incubate plates for 48 hours at 37ºC
You should come to lab next with with your lab notebook assignment.
There will be enough time at the beginning of week 3 to observe your plates and finish the results and conclusions.
Also remember to have your Pre-Lab write-up (purpose, procedure, data table) for Exercise 3: Enzymes at the beginning of class.