Medical Microbiology Lab Equipment

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Questions and Answers

What role do anion and cation exchange resins play in deionisation?

They remove ions from water. (correct)

They neutralize acids and bases.

They add minerals back to water.

They separate impurities by size.

What indicates that the ion exchange resin in the deioniser needs to be replaced?

The resin changes color. (correct)

The resin shrinks in size.

The resin becomes transparent.

The resin begins to dissolve.

What is the primary function of the autoclave in the sterilization process?

To use steam under pressure to kill microbes. (correct)

To maintain dry conditions during sterilization.

To freeze the items being sterilized.

To create a vacuum around the items.

What happens to the steam when it meets the cooler surfaces in the autoclave?

It condenses and releases latent heat. Signup and view all the answers

Why should ion exchange resins in a deioniser be protected from sunlight?

Sunlight causes them to degrade and lose effectiveness. Signup and view all the answers

What is the primary purpose of using a swing-out rotor in a centrifuge?

To allow for horizontal separation of particles. Signup and view all the answers

Which of the following safety practices is NOT recommended during the operation of a centrifuge?

Opening the lid while the centrifuge is still running. Signup and view all the answers

During an emergency breakage in the centrifuge, what is the recommended initial action?

Wait for at least 30 minutes before opening. Signup and view all the answers

What component is essential for maintaining the desired temperature in an incubator?

Thermostat. Signup and view all the answers

Which item should never be used to clean a centrifuge?

All-purpose cleaner. Signup and view all the answers

What is a characteristic feature of fixed-angle rotors in centrifuges?

They maintain a slanted separation during operation. Signup and view all the answers

Which type of incubator is generally recommended for bacteriological cultures?

Incubator. Signup and view all the answers

Why is it important to use padded sleeves in centrifuge buckets?

To prevent breakages caused by debris. Signup and view all the answers

What is the minimum temperature and duration needed for sterilization of certain materials in an oven without a fan?

2 to 2½ hours at 160°C Signup and view all the answers

What is the primary function of a laboratory autoclave?

To achieve moist sterilization at increased pressure Signup and view all the answers

Why is it essential to remove all air from the autoclave before sterilization?

Air prevents steam from reaching certain materials Signup and view all the answers

At what pressure does the safety valve of the autoclave begin to release excess steam?

15 lb pressure Signup and view all the answers

What must be done immediately after the holding period in the autoclave is completed?

Turn off the heater and cool the autoclave Signup and view all the answers

What type of materials should be used to ensure an airtight seal on the autoclave lid?

Asbestos washer Signup and view all the answers

What can be a consequence of not fully eliminating air from the autoclave chamber?

Before having enough temperature for sterilization Signup and view all the answers

What can hinder steam penetration into porous materials during the sterilization process?

The air present in the chamber Signup and view all the answers

What should be done before using a high power objective on a microscope?

Ensure the iris diaphragm is opened and the condenser is focused. Signup and view all the answers

How should a microscope be moved to prevent mechanical damage?

Carry it by its fixed upright stand and foot. Signup and view all the answers

What is the primary purpose of a centrifuge?

To separate particles from fluids based on weight. Signup and view all the answers

What should be done with oil immersion objectives after use?

Clean them immediately after each use. Signup and view all the answers

What is the correct sequence for viewing a specimen under a microscope?

Focus on the specimen with coarse adjustment, then switch to fine adjustment. Signup and view all the answers

Before observing a specimen under high power, what adjustment should be made to the condenser?

Fully rack it up and ensure it is properly centered. Signup and view all the answers

When cleaning a microscope, which of the following components need to be wiped free from dust?

Condenser lenses and mirror. Signup and view all the answers

What should be used to clean contaminated eyepieces inside a microscope?

Distilled water or a soft brush. Signup and view all the answers

What is the primary temperature setting for laboratory incubators to optimize the growth of most pathogenic organisms?

37°C Signup and view all the answers

Which of the following is NOT a recommended step for maintaining a laboratory water bath?

Seal uncapped tubes with a lid. Signup and view all the answers

What should be checked before placing glassware in a hot air oven for sterilization?

The glassware should be perfectly dry. Signup and view all the answers

What temperature range is generally used in a hot air oven for sterilizing materials?

160°C - 180°C Signup and view all the answers

Why should tap water be avoided in a water bath?

It may cause salt deposits that can damage the inner cells. Signup and view all the answers

What is the purpose of plugging test tubes and flasks with cotton wool before sterilization?

To avoid contamination from the environment. Signup and view all the answers

How often should the temperature of the incubator be checked before use?

Before every incubation Signup and view all the answers

In what time frame should an incubator be checked for signs of wear?

Every 3 - 6 months Signup and view all the answers

What is the primary reason to use heat-resistant glassware when heating liquids?

To prevent cracking from thermal expansion Signup and view all the answers

What cleaning procedure is recommended for new glassware to ensure it is safe for use?

Place in 1% HCl overnight and then autoclave Signup and view all the answers

Why is it necessary to loosely cap screw-capped tubes or flasks when heating?

To allow steam to escape and prevent cracking Signup and view all the answers

Which situation would require the autoclaving of glassware?

When glassware contains infectious materials like tubercle bacilli Signup and view all the answers

What is a chemical cleaning method for glassware used in biochemical work?

Using potassium dichromate/acid solution Signup and view all the answers

During the cleaning process, why is it important to handle potassium dichromate/acid solution with care?

It is highly corrosive and can cause burns Signup and view all the answers

Which cleaning option is suitable for glassware contaminated with infective materials?

Place in a 3% lysol solution until ready to wash Signup and view all the answers

What is a common consequence of using thick-walled glassware when diluting concentrated acids?

Increased risk of cracking due to heat evolved Signup and view all the answers

Study Notes

Basic Equipment in Medical Microbiology Laboratory

Microscopy: An indispensable tool for magnifying small objects. It can be monocular or binocular. Parts include the stand, body, and optical lenses. The stand holds the body and lenses, Has a stage for specimen placement with clips, and coarse/fine focusing mechanisms. Light source with diaphragm and filter for adjusting light intensity.
Centrifuge: Used for separating particles from fluids based on their weight. Has different types of rotors (swing-out or angled).
Incubator: Maintains constant temperature for bacterial cultures, usually at 37°C. Has thermostats.
Water bath: Keeps liquids at a constant temperature for cultures or tests.
Hot air oven: Sterilizes materials that don't react to high heat, like glass. Usually heated to 160-180°C for a certain time to sterilize.
Autoclave: Sterilizes using moist heat at high pressure and temperature. Steam condenses, releasing heat, killing microbes. Important, all air must be expelled, for a pure steam treatment.
Weighing balance: Accurately measures materials for laboratory work. Different types exist, some needing separate weights.
Glassware (Petri Dishes, Pipettes, Beakers, Flasks etc.): Various forms utilized for holding liquid cultures, specimens, or for measuring.
Safety Cabinets: Protect laboratory personnel from harmful substances.
Inoculation loop: Used to transfer microorganisms from one place to another.
Petri dishes: Small, shallow dishes used to cultivate microorganisms.
Test tube racks: Holds test tubes.
Petri dishes: Used to cultivate or grow microorganisms.
Vortex mixer: Mixes samples and solutions.
Refrigerator: Stores samples and supplies at a cold temperature.
Deionizer: Produces distilled water.

Care of Equipment

Microscope: Kept from direct sunlight or excessive heat. Clean lenses with specific materials, and avoid touching the optics directly.
Incubator: Positioned on a level surface, and regular cleaning and plugging of electricity is recommended.
Water Baths: Be sure to fill with clean water and use it only for incubation purposes.
Incubators: Level position, careful cleaning to avoid contamination, and regular checks/maintaining the temperature.
Centrifuge: Careful use to prevent damage, balancing, making sure tubes are securely placed, and not using it near possible dangers.
Glassware: Perfectly dry before use in sterilization ovens. Properly sterilized and cleaned glassware to prevent contamination.

Additional Notes

Cleaning solutions/procedures vary depending on the specific glassware or equipment.
Sterilization methods vary; autoclave requires hot/moist/high-pressure sterilization, and hot-air sterilization uses dry heat.

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Description

This quiz covers essential equipment used in a medical microbiology laboratory, including microscopy, centrifuges, incubators, and autoclaves. Test your knowledge on the purpose and functioning of each tool and their significance in microbiological practices.