Interview Questions.

Question 1. How Are Staining Techniques Classified?

Answer :

Simple stain: wherein simplest one stain is used and all micro organism are stained in addition. Eg: F1ethylene blue, dilute carbol fuchsin
Differential staining: where one of a kind micro organism stain otherwise to a commonplace staining method relying on their physiological houses. Eg: Gram’s stain and Acid fast staining
Special stain: in which structures of bacteria like spores. Granules. Tablet and many others are verified. Eg: silver impregnation approach for demonstration of spirochetes. Feulgen stain for demonstration of nucleus. Sudan black stain for demonstration of lipid vacuoles. Ryu’s stain for demonstration of flagella. Albert’s stain for demonstration of metachromatic granules.
Negative staining: in which the history is stained with an acidic dye which includes India ink or Nigrosin. Used for demonstration of drugs.
Question 2. How Are Stains Classified?

Answer :

Stains are classified based totally on the pH in their chromophore (coloration bearing ion) into acidic, fundamental and impartial. Acidic dyes have anionic chromophore

eg.. Sodium+ eosinate-. Basic dyes have cationic chromophore eg.. MetFiylene blue+ chloride-. Acidic dyes integrate greater strongly with cytoplasmic additives of micro organism, specially the nucleus this is primary in nature. Neutral dyes have both acidic and fundamental element that nullity each other.

They are Romanowsky’s stain and are used in staining parasitic bureaucracy. Stains may be either herbal (eg: carmine and hematoxylin) or coal-tar derivatives /aniline stains (eg: methylene blue. Crystal violet). Supravital (cells removed from the frame) and intravital (cells still a part of the body).

Nursing Interview Questions
Question 3. What Is Polychrome Methylene Blue?

Answer :

LoetTler’s methylene blue solution dealt with with Potassium hydroxide turns into Polychrome methylene blue after prolonged garage with shaking. Used in McFadyean’s reaction for Bacillus anthracis in blood movies and demonstration of metachromatic granules of Corynebacterium diphtheriae.

Question four. Who Invented Gram Stain?

Answer :

Hans Christian Gram invented this stain in 1884. The unique formulation turned into Aniline Gentian violet. Lugol’s iodine, absolute alcohol and Bismark brown.

Question five. Which Are The Theories Of Gram Staining?

Answer :

Cell wall theory: Cell wall of Gram effective micro organism are 40 times thicker than the ones of Gram bad cells, hence they are idea to help hold the dye-iodine complicated.
Lipid Content Theory: Cell envelope of Gram negative bacteria consists of an extra membrane (outer membrane). Consequently containing extra lipids than Gram fine micro organism. Acetone or alcohol dissolves the lipid consequently forming big pores in Gram negative micro organism thru which the dye-iodine complex leaks out. Alcohol/acetone dehydrates Gram tremendous micro organism shrinking the mobile wall and the remaining the pores.
Magnesium Ribonucleate Theory: A compound of magnesium ribonucleate and basic protein concentrated at the cell membrane facilitates Gram high-quality micro organism keep the primary dye. Gram negative bacteria do now not own this substance.
Cytoplasmic pH Theory: The cytoplasm of Gram superb bacteria are said to be extra acidic (2) than those of Gram negative ones (three). Hence the dye is said to bind with greater affinity to Gram wonderful cells.

BioChemistry Interview Questions
Question 6. Which Part Of The Bacteria Actually Gets Stained?

Answer :

It is the cytoplasm (mainly the nucleic acid) that receives stained and now not the mobile wall. Presence of an intact mobile wall is essential for maintaining Gram positivity. Cell wall poor paperwork including Mycoplasma and L bureaucracy are Gram bad.

Question 7. Which Are The Bacteria Or Bacterial Component That Can’t Be Stained By Gram Stain?

Answer :

Extremely slim bacteria together with Treponema
Cells containing waxy materials impermeable to stain inclusive of Mycobacteria
Minute intracellular bacteria along with Chlamydia and Rickettsia
Cell organelles along with tablet. Spore. Flagella and so on
Biotechnology Interview Questions
Question 8. Which Are The Alternatives Used In Gram Stain?

Answer :

Primary stain: Crystal violet. Methyl violet and Gentian violet
Mordant: Grams iodine, rarely Lugols iodine
Decolorizer: Alcohol, acetone. Acteone-alcohol mixture (1:1)
Counterstain: Dilute carbol fuchsin. Safranin, neutral pink. (Sandiford stain ror Gonococcj
Question nine. Which Are The Positive And Negative Controls For Gram Stain?

Answer :

Positive manage: Staphylococci
Negative manipulate: E.Coli. Pus cells
Biomedical Engineering Interview Questions
Question 10. What Are The Conditions When Gram Positive Bacteria Can Appear Gram Negative?

Answer :

When over-decolourized through either prolonged exposure to decolourizer or the usage of acetone by myself.
When cellular wall gets broken through publicity to lysozyme or cellular wall acting antibiotics which includes Penicillin.
Old cultures, where cell wall is weakened or movement of autolytic enzymes
Those micro organism which might be phagocytosed. Wherein cell wall is acted upon by means of lysosomal contents
Question eleven. Which Is The More Important Step In Gram Stain?

Answer :

Decolourization is the most critical step as this step differentiates between Gram tremendous and Gram terrible bacteria. Over-decolourization can result in Gram fantastic bacteria performing Gram bad and under-decolourization can result in Gram bad bacteria performing Gram effective.

Clinical Research Interview Questions
Question 12. What Are The Applications Of Gram Staining?

Answer :

Rapid presumptive analysis of sicknesses including bacterial meningitis
Selection of empirical antibiotics based on Gram stain finding
Selection of suitable way of life media based on Gram stain finding
Screening of quality of medical specimens. Which include sputum that should incorporate many pus cells and few epithelial cells
Counting of bacteria
Appreciation of morphology and kinds of micro organism in a scientific specimen 
Nursing Interview Questions
Question thirteen. Name A Fungus That Is Gram Positive?

Answer :

Candida sps

Question 14. What Are The Various Modifications Of Gram Stain?

Answer :

Kopeloll’ and Beerman’s (Primary stain: Methyl violet. Decolourizer: acetone or alcohol-acetone combination 1:1)
Jensen’s (Primary stain: Methyl violet, decolourizer: absolute alcohol. Counterstain: Neutral crimson)
Preston and Morrell’s (Primary stain: crystal violet. Decolourizer: iodine-acetone)
A.Igert’s (Primary stain: Carbol gentian violet. Decolourizer: Aniline-xylol). This is used to stain tissue sections.
Question 15. What Is Acid Fast Staining?

Answer :

Certain micro organism or their structures have the capability to keep the number one dye (strong carbol fuchsin) and withstand clecolourization by means of vulnerable mineral acids together with H2S04. HCI. Such bacteria or their shape are termed acid speedy and this belongings is termed acid fastness. There are  sorts of acid fast staining, the recent method and the cold method. The hot technique (Ziehl-Neelsen) entails heating the slide whilst the bloodless strategies inclusive of Kinyoun’s and Gabbett’s do no longer involve heating the slide.

Food and Nutrition Interview Questions
Question 16. Who Introduced Acid Fast Staining?

Answer :

Ehrlich in 1882 found acid fastness. The authentic technique involved staining with aniline-gentian violet and decolourization with sturdy nitric acid.

It changed into later improved through Ziehl and Neelsen.

Question 17. Why Are Mycobacteria Acid Fast?

Answer :

The mobile partitions of Mycobacterla are made from waxy substance, Mycolic acid that Is particularly Impermeable to regular stainIng techniques. But, through apphcation of warmth and a mordant (phenol), the mobile may be stained The motive of heating is to melt the waxy fabric of the mobile wall and permit the stain to enter the mobile. Basic fuchsin is greater soluble in phenol and phenol is a better solvent for lipids and waxes.

Pharmaceutical Quality Assurance Interview Questions
Question 18. What Are The Components Of Ziehi-neelsen Stain?

Answer :

Primary stain: Strong Carbol Fuchsin (incorporate Basic fuchsin and Phenol)
Decolourizer 20% sulphuric acid
Counterstain LoelTler’s Methylene blue or 1% Malachite green, Picric acid for shade-blind workers
BioChemistry Interview Questions
Question 19. What Is Acid-alcohol Decolourizer?

Answer :

three% HCI in 95% alcohol (methylated spirit). This is beneficial in dilrerentiating saprophytic Mycobacteria from pathogenic Mycobacteria Pathogenic Mycobacteria are both acid and alcohol fast but saprophytic Mycobacterla are handiest acid-speedy Saprophytic Mycobacterla can get declourized by means of alcohol. Ninety five% alcohol may be used as a secondary decolorizer after decolourizing with acid Especially used in staining smears prepared from urine that may contain Mycobacterium smegmatis.

Question 20. Which Are The Various Dilutions Of Sulfuric Acid Used?

Answer :

Mycobacterlum leprae - 5% H2S04
Oocysts of Cryptosporidium. Isospora - 1 % H2S04
Tissue sections containing Actinomyctes. Nocardia - 1 % H2S04
Cultures of Nocardia - 0.Five% H2S04
Bacterial spores - zero.25-0.Five% H2S04
Cell Biology Interview Questions
Question 21. What Are Cold Methods Of Acid Fast Staining?

Answer :

The  methods particularly Kinyoun’s and Gabbetts dont involve heating of slides, for this reason known as cold techniques. Heating is substituted through expanded concentration of phenol and prolonging the period of staining. Kinyoun’s approach is favoured for detection of Cryptosporidium oocysts in fecal samples. Gabbetts approach has decolourizer and counterstain in a single solution.

Question 22. Why Should The Slide Be Flooded With Strong Carbol Fuchsin?

Answer :

For uniform distribution of warmth, in any other case the slide may wreck.

Question 23. What Are The Precautions To Be Taken While Preparing Or Observing Smears For Afb?

Answer :

A new slide have to be used for every specimen. Because scratch marks may additionally deliver fake superb.
A uniform smear from thick portion of the sputum should be made.
Staining jars must not be used to staining smear as there's hazard to go contamination
Fresh blotting paper must be used for each smear for drying the slide to save you transfer from one slide to some other.
Question 24. How To Interpret The Smear?

Answer :

At least 100 oIl Immersion fields ought to be considered before maintaining the smear as terrible The sensitivity of smear Is low due to the fact It requires the presence of 104 bacillilml to be smear fantastic. If the variety of bacilli is less than this, the probabilities of detecting them are much less In any such case, the sample ought to be subjected to concentration strategies including Petroff s technique If the smear Es fine for AFB. It need to count/graded Failure to locate any AFB does no longer rule tuberculosis Grading of smears has prognostic value.

Biotechnology Interview Questions
Question 25. How Is The Smear Graded?

Answer :

Smears are graded depending at the quantity of bacilli seen

3-nine bacilli/complete smear: +
10 bacilli/complete smear ++
10 bacilli/in most oil Immersion fields: +++
Question 26. What Other Methods Are Available For Staining Mycobacteria?

Answer :

Sputum smears for Mycobacterla can be stained by fluorescent dyes along with Auramine and Rhodamlne as they've affinity for mycolic acid In their cell walIs The fluorescent microscopy is useful in screening big number of specimens. Large location of smear may be quickly determined that too under high energy dry goal.

Question 27. What Is Beaded Appearance Of Mycobacteria?

Answer :

Beaded appearance is used to explain the arrival of Mycobacterla while the cell doesn’t stain uniformly. Displaying stained and unstained regions. These paperwork are common in Mycobacterium tuberculosis whilst Mycobacterium bovis stains uniformly. Most saprophytic Mycobacteria stain uniformly.

Biomedical Engineering Interview Questions
Question 28. What Are Metachromatic Granules?

Answer :

Metachromatic granules are pol’ymetaphosphate reserves produced by means of Corynebacterium diphtheriae in nutritious medium. These granules also are known as Babes Ernst granules. ‘blutin granules. Polar bodies and so forth. They are referred to as metachromatic granules due to they show off metachromasia.

A belongings wherein the granules seem in a color different from that of the dye used When stained with polychrome methylene blue, they seem purple They are produced In abundance In serum containing medium inclusive of Loeffler’s serum slope.

Question 29. Which Are The Ways To Demonstrate These Granules?

Answer :

Albert’s stain. Neissers stain, Ponder’s stain and Pugh’s stain They can be demonstrated as retractile bodies in moist mount or barely greater gram superb systems in Gram stain.

Question 30. Why Are The Bacilli Arranged At Angles To Each Other?

Answer :

The bacdh are arranged at angles to each different reminiscent of English letter V or L or Chinese letter (cuneiform) pattern due to the fact the daughter cells doWt separate absolutely after cellular dMslon (binary rission).

Question 31. What Do Albert A(1) And B(2) Solution Contain?

Answer :

Solution A(1) contains Toluidine blue, Malachite green, Glacial acetic acid and Alcohol even as answer eight(2) includes iodine and potassium iodide In distilled water.

Question 32. What Is Sterilization And Disinfection?

Answer :

The procedure of kdling all hying forms which includes spores is referred to as sterilization and the method of killing of most effective the vegetative form of pathogenic bacteria in addition to other microbes is disinfection

Question 33. What Is The Temperature And Time Employed To Sterilize The Articles In Hot Air Oven?

Answer :

one hundred sixty°C for 60 mInutes

Clinical Research Interview Questions
Question 34. What Are The Conditions Of Sterilization In An Autoclave?

Answer :

121°C for 15 mins at 15 pounds in line with square inch of strain

Question 35. What Are The Articles Sterilized In A Hot Air Oven?

Answer :

Glassware’s, metallic gadgets like scissors and forceps, swabs. Powder. Oils and grease.

Question 36. What Are The Articles Sterilized In An Autoclave?

Answer :

Culture media, gloVes. Cotton and clothes.

Food and Nutrition Interview Questions
Question 37. How Are Heat Labile Fluids Such As Serum And Antibiotic Solutions Sterilized?

Answer :

By filtration.

Question 38. How Is Air Sterilized?

Answer :

By High Elliciency Particulate Air (HEPA) filters.

Question 39. Name Some Disinfectants?

Answer :

Phenol. Lysol, Formaldehyde. Sodium hypochlorite.

Question forty. What Are Antiseptics?

Answer :

Antiseptics are moderate disinfectants that can be effectively used on pores and skin and mucous membranes.

Pharmaceutical Quality Assurance Interview Questions
Question forty one. Quaternary Ammonium Compounds?

Answer :

Quaternary ammonium compounds are undoubtedly charged polyatomic ions, which listen on the mobile surface and adjust the physical and chemical homes of the membrane, thus killing the cefl. Examples inlcude Benzalkonium chloride and Cetrimonium bromide.

Question 42. What Do Popular Brands Of Antiseptics Such As Dettol Or Savlon Contain?

Answer :

The active factor of Dettol is chloroxylenol whereas Savlon consists of a aggregate of Cetrimide and Chiorhexidine.

Cell Biology Interview Questions
Question 43. Which Are The Active Ingredients Of Commercial Mouthwashes?

Answer :

The lively components consist of Chlorhexidine. Triclosan. Thymol. Cetylpyridinium Chloride, and alcohol. The composition varies across brands.

Question 44. What Are Chemisterilants?

Answer :

These are the chemical substances used for sterilization. They are 2% Gluteraldehyde (cidex). Ethylene Oxide (EO). Formaldehyde + steam and Beta — Propiolactone (BPL).

Question 45. Which Iodine Compounds Are Used In Antiseptics?

Answer :

Tincture Iodine - 2% of Iodine in 70% alcohol - lodophore - Povidone Iodine.
Name some antiseptics.
Chlorhexidine. Chloroxylenol. Spirit (70% alcohol), tincture of Iodine. H202.
Question 46. Which Is The Best Disinfectant Used In Serology?

Answer :

Sodium hypochlorite or Calcium hypochlorite

Question 47. How Are The Clinical Specimen Disinfected Before Discarding?

Answer :

By treating them with disinfectant, boiling or autoclaving and in the end by means of incineration

Question forty eight. How Are The Articles Commercially Sterilized?

Answer :

Gamma rays. Electron beams and Ethylene oxide

Question 49. How Are Hemodialyzers And Endoscopes Disinfected?

Answer :

Glutaraldehyde or a aggregate of peracetic acid and hydrogen peroxide may be used.

Question 50. How Does Ethylene Oxide Sterilize?

Answer :

Alkylation (hydrogen atom is changed with an alkyl group) of protein. DNA. And RNA afFects bacterial metabolism and replication. EQ gasoline (eight.5%) is often mixed with stabilizers along with CO2 (ninety one five%) or hydrochlorofluorocarbons (HCFC). This requires high humidity (40-eighty%) and lengthy exposure instances (1-6 hrs).

Question fifty one. What Is Duckering?

Answer :

Ducking Is a procedure of inactivation of Anthrax spores in animal merchandise including wool, hairs or bristles. It became delivered by Elmhirst Duckering, an enginer at wool manufacturing unit. This is a stay-step procedure. Every lasting for 10 minutes and performed at 40.5°c.

Immersion in zero.25-0.Three% alkali
immersion in soapy water
immersion in 2% formaldehyde
secondimmersion in 2% formaldehyde
rinsinq in water
Question fifty two. What Are The Various Filters?

Answer :

Porcelain filters. Seitz (asbestos) filters. Sintered glass filters. Membrane filters and HEP filters.

Question fifty three. What Are The Uses Of Inspissator?

Answer :

It disinfects and solidifies egg and serum containing media which include U medium and LoelTiers serum slope.

Question fifty four. How Is Operation Theatre Sterilized?

Answer :

By fumigation with formaldehyde.

Question fifty five. What Is Meant By Cold Sterilization?

Answer :

Use of excessive-electricity radiation which include gamma rays to sterilize an article.