Microbiology Quiz for BSN 1st Semester Conducted by NRA

What is the primary purpose of Gram staining?

• To increase bacterial growth

• To classify bacteria into Gram-positive and Gram-negative

• To dissolve bacterial cell walls

• To kill bacteria

Which dye is used as the primary stain in Gram staining?

• Iodine

• Crystal violet

• Safranin

• Methylene blue

Gram-positive bacteria retain the crystal violet stain because of their:

• Thin peptidoglycan layer

• Absence of a cell wall

• Thick peptidoglycan layer

• Thick lipid layer

What is the decolorizing agent used in Gram staining?

• Iodine

• Alcohol

• Water

• Acid

After decolorization, Gram-negative bacteria appear:

• Purple

• Pink

• Blue

• Colorless

What is the causative organism of tuberculosis?

• Salmonella typhi

• Mycobacterium tuberculosis

• Vibrio cholera

• Escherichia coli

What is the gold standard for diagnosing TB?

• Sputum smear for acid-fast bacilli (AFB)

• Chest X-ray

• Mantoux test

• Blood culture

Typhoid fever is caused by:

• Salmonella typhi

• Corynebacterium diphtheriae

• Vibrio cholera

• Mycobacterium tuberculosis

Which vaccine is used for TB prevention?

• BCG

• MMR

• TAB

• DPT

Cholera is characterized by:

• Dry cough

• Constipation

• Rice-watery stool

• Bloody diarrhea