MLS Laboratory Equipment & Techniques 1 — Questions and Answers
Question 1: Which piece of laboratory equipment is used to measure the absorbance of a solution at a specific wavelength?
- Centrifuge
- Spectrophotometer (Correct answer)
- Microscope
- Pipette
Correct answer: Spectrophotometer
A spectrophotometer is an analytical instrument used to measure the intensity of light absorbed or transmitted by a solution at specific wavelengths. It quantifies the amount of light absorbed, which is directly proportional to the concentration of the analyte in the solution, according to Beer-Lambert's Law. This makes it essential for various quantitative assays in a clinical laboratory, such as measuring enzyme activity or analyte concentrations.
Question 2: Which laboratory technique is used to separate components of a mixture based on their density?
- Chromatography
- Centrifugation (Correct answer)
- Filtration
- Electrophoresis
Correct answer: Centrifugation
Centrifugation is a laboratory technique that uses centrifugal force to separate components of a mixture based on their density. By spinning samples at high speeds, denser particles are forced to the bottom of the tube (forming a pellet), while lighter components remain in the supernatant. This technique is widely used to separate blood components (like plasma from red blood cells), cells from culture media, or macromolecules.
Question 3: Which type of pipette is used for highly accurate liquid volume measurements?
- Serological pipette
- Pasteur pipette
- Micropipette (Correct answer)
- Graduated cylinder
Correct answer: Micropipette
Micropipettes are precision instruments designed for highly accurate and reproducible measurement and transfer of very small liquid volumes, typically in the microliter range. They are essential in molecular biology, clinical diagnostics, and other laboratory applications where exact volumes are critical for experimental integrity and reliable results. Their adjustable volume settings and disposable tips ensure precision and prevent cross-contamination.
Question 4: What is the purpose of an autoclave in a clinical laboratory?
- Measure optical density
- Sterilize laboratory equipment (Correct answer)
- Analyze chemical composition
- Separate serum from blood
Correct answer: Sterilize laboratory equipment
An autoclave is a device that uses high-pressure saturated steam to sterilize laboratory equipment, media, and waste. The intense heat (typically 121°C or 134°C) and pressure effectively kill bacteria, viruses, fungi, and spores, ensuring aseptic conditions. This process is crucial for preventing contamination in experiments, preparing sterile reagents, and safely disposing of biohazardous materials in a clinical laboratory.
Question 5: Which technique is used to separate DNA fragments based on their size?
- Chromatography
- Centrifugation
- Gel electrophoresis (Correct answer)
- PCR
Correct answer: Gel electrophoresis
Gel electrophoresis is a molecular biology technique used to separate DNA fragments (as well as RNA and proteins) based on their size and electrical charge. DNA, being negatively charged, migrates through a gel matrix towards a positive electrode when an electric current is applied. Smaller fragments move faster and further through the gel pores than larger ones, allowing for their separation and subsequent visualization.
Question 6: What is the primary function of a fume hood in a laboratory?
- Store laboratory chemicals
- Protect users from harmful fumes (Correct answer)
- Sterilize equipment
- Measure sample absorbance
Correct answer: Protect users from harmful fumes
A fume hood is a critical safety device in laboratories designed to protect users from exposure to hazardous fumes, vapors, and particulate matter. It works by drawing air from the laboratory into the hood and exhausting it outside, creating a contained workspace. This prevents the inhalation of toxic substances and minimizes the risk of chemical exposure, ensuring a safer working environment.
MLS Laboratory Equipment & Techniques 1
Which piece of laboratory equipment is used to measure the absorbance of a solution at a specific wavelength?