College of Dentistry
CRN:20646
Monday 12:30
, CRN: 20646
Name of the experiment: Safety precautions, type of microscope, uses of tools & instruments
Aim: To be aware of the different instruments present in the laboratory and of the safety precaution to
help avoid any laboratory mishaps.
Safety precautions in the microbiology lab:
● Only necessary work material should be at or on the laboratory bench. Everything other than the
cultures and tools used in the practical should be off the lab bench. All other personal belongings
inside the allocated cupboard to keep the working place free of items. This is to prevent cluttering
of the workspace and to avoid exposing them to permanent stains, caustic chemicals, and
microorganisms used in the exercises.
● Wash hands with soap, wear lab coats and gloves prior to any lab experiment. The clothes worn in
the lab have to cover the entire body. For example, close-toed shoes while in the laboratory and
long pants. Moreover, long hair should be pulled back to keep it away from bacterial cultures,
bacticinerator or open flames.
● Clothing worn in the microbiology laboratory should be washed before being subsequently worn
in a facility such as a hospital, clinic or nursing home, or in an area of public food preparation.
● No consumption of any foods or drinks inside the laboratory.
● At the end of each laboratory session, make sure that all laboratory facilities and equipment are in
good working conditions. Any damages (no matter how small they are) have to be reported to the
laboratory instructor
● Recognize the worldwide sign for biohazards and be aware of where and how to dispose of all
waste products, including biohazard trash. It should be noted that all biohazard waste must be
autoclave sterilized before being disposed of.
● In case of any emergencies such as injuries, broken glass, spilling of hazardous liquids should be
reported immediately
● Treat all the microorganisms as potential pathogens that are capable of causing harm in
unexpected or unusual situations. If a student has a weakened immune system or has an illness,
this has to be reported to the laboratory instructor.
● Remove no equipment, medium, or microbiological cultures from the laboratory under any
circumstances.
● Disinfect the working area/laboratory bench before and after laboratory work.
Types of microscope:
1. Electron microscope: Electron microscopes are used to create high-resolution images of
biological and non-biological specimens. The utilization of electrons (which have very short
wavelengths) as the source of illuminating light leads to the
great resolution of electron microscopic images, which reveal
significant details on the structural basis of cell activity and
illness. Examples of details that the electron microscope can
yield include: Topography - The texture of an object's surface
features and how it appears (hardness/reflectivity)- ,
Morphology - The form and size of the particles that make up
the microorganism as well as its qualities (ductility, strength,
reactivity)-, Composition and crystallographic Information -
The arrangement of the atoms and the resulting properties-.
The magnification of the electron microscope is 10,000,000x.
The resolution of the electron microscope is 0.2 nm.
, CRN: 20646
2. Light microscope: A light microscope magnifies a specimen, generally a cell, using focused light
and lenses. It delivers light down a route that first concentrates it into a narrow beam, then passes
it through a sample to form an image. This image is then magnified by one or more lenses before
reaching the microbiologist’s eye or a camera. It is necessary to use thin specimens when using
this microscope to allow light to travel through it. Because most cells, whether bacterial or not,
are tiny and transparent, light may readily travel through them. It is important to note that light
microscopes offer minimal magnification and resolution. The magnification of the light
microscope is x2000. The resolution of the light microscope is 200 nm.
3. Fluorescent microscope: The magnifying characteristics of a light microscope are combined with
the fluorescence emitting properties of molecules in a fluorescence microscope. A high-intensity
light source is used in fluorescence microscopy to stimulate a fluorescent molecule termed a
fluorophore in the specimen viewed under the microscope. Fluorophore is used to label the
samples, which absorbs the high-intensity light from the source and
emits a lower-energy light with a longer wavelength. Filters are used to
isolate the fluorescent light from the surrounding radiation, enabling the
microbiologist to perceive just the fluorescing substance. The final
image of the fluorescent microscope is an enlarged version of the
specimen being analyzed. The magnification for the fluorescent
microscope is 100×. The resolution of the fluorescent microscope is
limited by diffraction to about 180 nm in the focal plane and to about
500 nm along the optic axis.
Bacterial identification:
1. Macroscopical examination: Preparation of the microscopic slide to
view the specimen under the microscope with greater magnification.
This allows us to observe the features and structures of the microorganisms that are otherwise
invisible to the naked eye.
2. Microscopical examination: Growing the bacteria on the selective media and observing the
morphology of their colonies by the naked eye; usually every colony has its own characteristic
and unique morphological characteristic.
3. Biochemical test: A series of different tests that are performed to identify the different bacteria
based on their biochemical activities. Examples include catalase test, urease test and indole test.
4. Antibiotic sensitivity test
5. Serology test: A series of different tests that can be used on the antibodies and antigens of
bacteria and viruses. Examples of tests include ELISA and immunofluorescence
Instruments present in the lab
Measured wire loop Pick up and transfer sample from a culture
of microorganisms
CRN:20646
Monday 12:30
, CRN: 20646
Name of the experiment: Safety precautions, type of microscope, uses of tools & instruments
Aim: To be aware of the different instruments present in the laboratory and of the safety precaution to
help avoid any laboratory mishaps.
Safety precautions in the microbiology lab:
● Only necessary work material should be at or on the laboratory bench. Everything other than the
cultures and tools used in the practical should be off the lab bench. All other personal belongings
inside the allocated cupboard to keep the working place free of items. This is to prevent cluttering
of the workspace and to avoid exposing them to permanent stains, caustic chemicals, and
microorganisms used in the exercises.
● Wash hands with soap, wear lab coats and gloves prior to any lab experiment. The clothes worn in
the lab have to cover the entire body. For example, close-toed shoes while in the laboratory and
long pants. Moreover, long hair should be pulled back to keep it away from bacterial cultures,
bacticinerator or open flames.
● Clothing worn in the microbiology laboratory should be washed before being subsequently worn
in a facility such as a hospital, clinic or nursing home, or in an area of public food preparation.
● No consumption of any foods or drinks inside the laboratory.
● At the end of each laboratory session, make sure that all laboratory facilities and equipment are in
good working conditions. Any damages (no matter how small they are) have to be reported to the
laboratory instructor
● Recognize the worldwide sign for biohazards and be aware of where and how to dispose of all
waste products, including biohazard trash. It should be noted that all biohazard waste must be
autoclave sterilized before being disposed of.
● In case of any emergencies such as injuries, broken glass, spilling of hazardous liquids should be
reported immediately
● Treat all the microorganisms as potential pathogens that are capable of causing harm in
unexpected or unusual situations. If a student has a weakened immune system or has an illness,
this has to be reported to the laboratory instructor.
● Remove no equipment, medium, or microbiological cultures from the laboratory under any
circumstances.
● Disinfect the working area/laboratory bench before and after laboratory work.
Types of microscope:
1. Electron microscope: Electron microscopes are used to create high-resolution images of
biological and non-biological specimens. The utilization of electrons (which have very short
wavelengths) as the source of illuminating light leads to the
great resolution of electron microscopic images, which reveal
significant details on the structural basis of cell activity and
illness. Examples of details that the electron microscope can
yield include: Topography - The texture of an object's surface
features and how it appears (hardness/reflectivity)- ,
Morphology - The form and size of the particles that make up
the microorganism as well as its qualities (ductility, strength,
reactivity)-, Composition and crystallographic Information -
The arrangement of the atoms and the resulting properties-.
The magnification of the electron microscope is 10,000,000x.
The resolution of the electron microscope is 0.2 nm.
, CRN: 20646
2. Light microscope: A light microscope magnifies a specimen, generally a cell, using focused light
and lenses. It delivers light down a route that first concentrates it into a narrow beam, then passes
it through a sample to form an image. This image is then magnified by one or more lenses before
reaching the microbiologist’s eye or a camera. It is necessary to use thin specimens when using
this microscope to allow light to travel through it. Because most cells, whether bacterial or not,
are tiny and transparent, light may readily travel through them. It is important to note that light
microscopes offer minimal magnification and resolution. The magnification of the light
microscope is x2000. The resolution of the light microscope is 200 nm.
3. Fluorescent microscope: The magnifying characteristics of a light microscope are combined with
the fluorescence emitting properties of molecules in a fluorescence microscope. A high-intensity
light source is used in fluorescence microscopy to stimulate a fluorescent molecule termed a
fluorophore in the specimen viewed under the microscope. Fluorophore is used to label the
samples, which absorbs the high-intensity light from the source and
emits a lower-energy light with a longer wavelength. Filters are used to
isolate the fluorescent light from the surrounding radiation, enabling the
microbiologist to perceive just the fluorescing substance. The final
image of the fluorescent microscope is an enlarged version of the
specimen being analyzed. The magnification for the fluorescent
microscope is 100×. The resolution of the fluorescent microscope is
limited by diffraction to about 180 nm in the focal plane and to about
500 nm along the optic axis.
Bacterial identification:
1. Macroscopical examination: Preparation of the microscopic slide to
view the specimen under the microscope with greater magnification.
This allows us to observe the features and structures of the microorganisms that are otherwise
invisible to the naked eye.
2. Microscopical examination: Growing the bacteria on the selective media and observing the
morphology of their colonies by the naked eye; usually every colony has its own characteristic
and unique morphological characteristic.
3. Biochemical test: A series of different tests that are performed to identify the different bacteria
based on their biochemical activities. Examples include catalase test, urease test and indole test.
4. Antibiotic sensitivity test
5. Serology test: A series of different tests that can be used on the antibodies and antigens of
bacteria and viruses. Examples of tests include ELISA and immunofluorescence
Instruments present in the lab
Measured wire loop Pick up and transfer sample from a culture
of microorganisms
