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Intro Microbio Lab 1: Introduction to the Microbiology Lab

Terms in this set (18)

Describe how to follow lab exercise protocols and take notes in the microbiology lab
-No personal belongings on lab counter (including papers, pens/pencils, eyeglasses); might become contaminated with infectious pathogens

-Before lab, read posted lab exercises and watch any demonstration videos; instructor will briefly describe the exercises at beginning of class

-Take notes on computer on post-lab and open lab exercise PDF document

-First portion of exercise relates to experiments performed in class; second portion relates to questions related to the text and your own research using reliable sources
Identify safety features in the microbiology lab
-Fire extinguisher to the right of the main entrance
-Two eyewash stations on the left side of the wall immediately after entering (one: stainless steel handle. Two: press down yellow handle)
-Emergency shower mounted to ceiling immediately after entering (pull down stainless steel handle)
-Telephone on back wall
List the actions you must complete upon arrival and prior to departure in the microbiology lab
Before lab:
-Place all personal items in cubbies at front of lab
-Disinfect bench with lysol/natural-Q and wipe with paper towel
-Use wipes to disinfect keyboard and mouse
-Wash your hands

After lab:
-Properly dispose of all trash and replace all materials used
-Disinfect lab bench and computer as above
-Wash hands
-Collect all belongings
Describe where to throw away the following types of waste: glass, biohazardous materials, gloves, and regular trash
-Glass: sharps container at back, right side of lab (if prepared slide, turn in to instructor)
-Culture tubes: back, right side of lab
-Used culture agar plates and swabs: biohazardous waste container (back, right side)
-Regular trash: placed in trash cans
Recognize the correct purpose for each type of the following microscopes: bright-field microscope, dark-field microscope, dissecting microscope, and electron microscope
-Bright-field: produces image made of light that is transmitted through a specimen; specimen restricts light transmission and appears dark against a bright background

-Dark-field: special condenser is added so that only the light reflected off the specimen enters the objective (bright specimen against dark background)

-Dissecting: light reflected from surface of an object (instead of through it) and into objective lens. Lenses designed for lower magnification to facilitate viewing of larger objects

Electron: uses electron beams focused on specimen by use of magnetic fields. High resolution. Allows visualization of sub-cellular compartments and large multi-protein complexes. Samples must be stained with heavy metals, which deflect electrons, to provide contrast in acquired image
--Types:
---Transmission EM: needs fixed, dehydrated specimens (preferred for visualizing structures within individual cells)
---Scanning EM: scans surface with electron beam to generate 3D image. Only surface details at lower resolution to TEM
Define and be able to calculate total magnification
First lens creates an image and the second magnifies. Thus, if first lens is 4x [the magnification of a human eye], it creates a 4x image that the second lens, 10x, magnifies. Sum total is the product of both lenses

4x * 10x = 40x
10x * 10x = 100x
40x * 10x = 400x
100x * 10x = 1000x
Define resolving power
Ability of a lens to show two adjacent objects as discrete or separate objects. Magnification and quality of lens and wave length of light that is measured affects resolving power. The shorter the wavelength, the better the resolving power

Unaided human eye: 0.2mm
Bright-field: 0.2 micrometers
SEM: 2-10 nanometers
TEM: 0.2 - 0.5 nanometers
Identify the various parts of the bright-field microscope
Eyepiece
Revolving Nosepiece
Objective lens
Stage clips
Mechanical Stage
Diaphragm (iris)
Light source
Base
Arm
Condenser lens
Coarse adjustment knob
Fine adjustment knob
Rotating head
On/Off switch
Illumination intensity control
X-Y translation mechanism
Identify and list the function of the various parts of a bright-field microscope
-Eyepiece: The lens one looks through. 10x lenses. Pointer inside right ocular

-Revolving Nosepiece: Holds objective lenses and can be rotated to change objective lens/power

-Objective lens: refracts light passing through specimen to produce magnified image. Comes in 4x, 10x, 40x, and 100x. Immersion oil needed for 100x

-Stage clips: Holds slide in place

-Mechanical Stage: flat platform where slides are placed

-Diaphragm (iris): Rotating disk directly under stage. Used to vary intensity and size of cone of light that is projected from light source up towards slide. Adjusted to improve contrast between background and specimen

-Light source: halogen bulb in base of microscope (provides light for specimen illumination)

-Base: Holds everything in place and is used to transport the microscope safely

-Arm: Used to transport microscope safely

-Condenser lens: Concentrates Light on specimen and makes illumination more uniform

-Coarse adjustment knob: Left side of microscope, larger focus knob used to greatly change focus of microscope

-Fine adjustment knob: Left side, smaller focus knob used to slightly change focus

-Rotating head: Contains delicate prism used to send image to the oculars and your eyes (head show be rotated so oculars are facing arm, when stored)

-On/Off switch: Obvious

-Illumination intensity control: knob control brightness of light directed at specimen

-X-Y translation mechanism:
--Y stage control knob: top knob, used to move slide vertically on mechanical stage
--X stage control knob: bottom knob, used to move slide horizontally on stage
Properly prepare to use the microscope
-If there is a dust cover on the microscope, remove and fold it. After neatly folding, place it in the middle of the bench so that it is out of the way.

-The power cord is neatly wrapped around the arm of the microscope. Carefully unravel the cord and plug in the microscope in the middle of the table.

-Never push or drag the microscope on the benchtop. Instead, always lift it to move it. Pushing or dragging the microscope on the benchtop causes it to bounce on the rubber feet on the bottom of the base of the microscope.
Properly focus the microscope with the 4x, 10x, and 40x objective lenses with a prepared slide of Euglena or Paramecium
Describe practical process underwent in lab
Define prokaryote and list the two domains in which prokaryotic organisms are found
Living cell that lacks a nucleus.

Archaea and Bacteria
State the differences between prokaryotes and eukaryotes
Does not contain membrane bound organelles unlike eukaryotes (therefore: no nucleus, nuclear membrane, mitochondria, endoplasmic reticulum, or golgi bodies)

Generally posses only a single, circular chromosome unlike eukaryotes' many linear chromosomes
State and describe the six types of morphologies and the four types of arrangements that can be observed in various bacteria
Morphologies:
-Coccus - sphere
-Bacillus - rod
-Spirillum - spirals (lasagna)
-Vibrios - slightly curved rods
-Spirochetes - thin, flexible cell walls; resemble corkscrew
-Filamentous - long strands like spaghetti

Arrangements:
-Single
-Diplo
-Strepto
-Sarcina: group of 8
-Staphylo
Properly focus the microscope with all objective lenses and identify the morphology and arrangement of a prepared slide of Escherichia coli or an unknown prepared slide
Describe as done in lab
Detail how to properly clean all objective lenses and immersion oil from a microscope slide and properly return the microscope to the storage cabinet
-Move stage down
-Clean oil from slide using lens wipe and liberal amount of lens cleaner
-Return slide to box
-Clean oil from lens using lens wipe and liberal amounts of lens cleaner
-Do not use lens wipe that has oil on it on any other slide
-Rotate scanning lens into position over stage
Describe the three groups found in the Protista kingdom
-Algae: plant like, green brown and red algae, diatoms (unicellular containing silica in cell walls), dinoflagellates (two flagella; responsible for red tides)

-Protozoans: animal like, amoeboid-like movement (Amoeba), ciliated unicellular protists (Paramecium)

-Decomposers: fungi like, acellular slime molds, cellular slime molds, water molds, has chitin in cell wall
Prepare or describe how to create a wet mount using pond water
-Take slide to pond water and place small drop of water in the middle of the slide using a disposable pipette
-Place cover slip on top
-Magnify specimen to 40x (total) to observe protists
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