10+ Quality Control Microbiologist Interview Questions and Answers

Procaryotic cells lack a nucleus and membrane-bound organelles, while eucaryotic cells have both.

• Procaryotic cells are smaller and simpler in structure than eucaryotic cells.

• Procaryotic cells have a single circular chromosome, while eucaryotic cells have multiple linear chromosomes.

• Procaryotic cells have cell walls made of peptidoglycan, while eucaryotic cells have cell walls made of cellulose or chitin.

• Examples of procaryotic cells include bacteria and archaea, while example...read more

Xylose Lysine Deoxycholate (XLD) agar is commonly used for the isolation and identification of Salmonella.

• Xylose Lysine Deoxycholate (XLD) agar is a selective and differential medium used for the isolation and identification of Salmonella.

• It contains xylose, lysine, and deoxycholate, which inhibit the growth of most other bacteria while allowing the growth of Salmonella.

• XLD agar also contains phenol red, which changes color in the presence of acid produced by Salmonella.

• Typic...read more

HEPA stands for High Efficiency Particulate Air. The pore size of a HEPA filter is typically 0.3 micrometers.

• HEPA stands for High Efficiency Particulate Air.

• HEPA filters are used to remove particles and contaminants from the air.

• The pore size of a HEPA filter is typically 0.3 micrometers.

• HEPA filters are commonly used in cleanrooms, hospitals, and HVAC systems.

70% IPA is used as it is more effective in killing microorganisms than higher concentrations.

• 70% IPA has a higher water content which allows it to penetrate the cell wall of microorganisms more effectively

• Higher concentrations of IPA can cause coagulation of proteins on the surface of microorganisms, making them more resistant to disinfection

• 70% IPA is less volatile than higher concentrations, allowing for longer contact time with the surface being disinfected

Gram staining is a technique used to differentiate bacteria into two groups: Gram-positive and Gram-negative.

• Prepare a heat-fixed bacterial smear on a glass slide

• Cover the smear with crystal violet stain for 1 minute

• Rinse the slide with water to remove excess stain

• Apply iodine solution to the slide for 1 minute

• Rinse the slide with water again

• Decolorize the slide with alcohol or acetone for a few seconds

• Rinse the slide with water once more

• Counterstain the slide with safranin f...read more

ACE-2 receptor stands for Angiotensin-Converting Enzyme 2 receptor. It is a protein that is found on the surface of many cell types.

• ACE-2 receptor is formed by the ACE2 gene.

• It is primarily found in the lungs, heart, kidneys, and intestines.

• ACE-2 receptor plays a crucial role in regulating blood pressure and cardiovascular function.

• It is also the receptor that allows the SARS-CoV-2 virus to enter human cells and cause COVID-19.

• ACE-2 receptor is a potential target for developi...read more

SCDM and FTGM are culture media used for microbial growth and identification.

• SCDM stands for Sabouraud Dextrose Chloramphenicol Medium and is used for fungal isolation and identification.

• FTGM stands for Fluid Thioglycollate Medium and is used for anaerobic bacterial growth.

• SCDM contains dextrose, peptone, chloramphenicol, and agar.

• FTGM contains thioglycollate, dextrose, cysteine, and agar.

• Both media are commonly used in microbiology laboratories for microbial culture and iden...read more

Bacteria can come in various colors and types, indicating their characteristics and potential impact on health and environment.

• Bacteria can be classified based on their shape, such as cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

• Different types of bacteria can have distinct colors, such as Gram-positive bacteria appearing purple or blue after staining, while Gram-negative bacteria appear pink or red.

• Some bacteria produce pigments that give them unique...read more

GPT stands for Glutamic Pyruvic Transaminase, an enzyme found in the liver and used as a marker for liver damage.

• GPT is also known as Alanine Transaminase (ALT).

• Elevated levels of GPT in the blood can indicate liver damage or disease.

• GPT levels are often measured in routine blood tests to monitor liver function.

• Certain medications and alcohol consumption can also affect GPT levels.

• GPT is not specific to liver damage and can also be elevated in other conditions such as muscle ...read more

A negative plate is a sterile plate that is used as a control to ensure that the growth observed on a test plate is due to the sample being tested.

• Negative plates are used in microbiology to ensure that the growth observed on a test plate is not due to contamination.

• They are typically sterile plates that are not inoculated with the sample being tested.

• If growth is observed on a negative plate, it indicates that there was contamination in the testing process.

• Negative plates ar...read more

Pathogenic organisms can be either gram-positive or gram-negative.

• Gram-positive organisms have a thick peptidoglycan layer in their cell wall, which retains the crystal violet stain in the Gram staining process.

• Gram-negative organisms have a thinner peptidoglycan layer and an outer membrane that contains lipopolysaccharides, which makes them more resistant to antibiotics.

• Examples of gram-positive organisms include Staphylococcus aureus and Streptococcus pneumoniae, while exam...read more

Autoclave validation is done by physical and biological methods to ensure proper sterilization.

• Physical methods include temperature and pressure monitoring.

• Biological methods include spore testing using Bacillus stearothermophilus or Geobacillus stearothermophilus.

• Validation should be done initially, after any repairs or maintenance, and periodically thereafter.

• Validation records should be maintained for regulatory compliance.

Autoclaves are used for sterilization. There are different types of autoclaves based on their usage and design.

• Gravity displacement autoclave

• Pre-vacuum autoclave

• Steam-flush pressure-pulse autoclave

• High-speed pre-vacuum sterilizer

• Tabletop autoclave

• Vertical autoclave