TEXTBOOK OF DIAGNOSTIC MICROBIOLOGY
7 2026 FINAL PRACTICE PAPER QUESTIONS
AND ANSWERS
◉ Sanitization. Answer: Substantial reduction of microbial
populations to meet health-related standards.
◉ X-rays (sterilization). Answer: High-energy photons generated by
electrical discharge, employed for surface and package sterilization.
◉ Residual activity. Answer: The continued antimicrobial effect of a
substance after the initial application, useful for prolonged
protection.
◉ Alcohols (ethanol/isopropanol). Answer: Organic solvents that
coagulate proteins and disrupt membranes; fast-acting but
evaporate quickly.
◉ Disinfection-by-products (DBPs). Answer: Potentially harmful
chemicals formed when chlorine reacts with organic matter during
water treatment.
, ◉ Heat-sensitive materials. Answer: Plastics and polymers that can
be damaged by high temperatures, requiring non-thermal control
methods.
◉ Gamma rays. Answer: Electromagnetic radiation emitted from
radioactive isotopes, used for deep penetration sterilization.
◉ Autoclave. Answer: Pressurized steam system that operates at
121 °C and 15 psi for at least 15 minutes to achieve sterility.
◉ Pasteurization. Answer: A short-duration heat treatment that
reduces spoilage organisms and destroys pathogens while
preserving the product's qualities.
◉ Biguanides (chlorhexidine). Answer: Compounds that damage
membranes and inhibit enzymes; persistent on skin but ineffective
against spores.
◉ Biosafety Level 3. Answer: Work with serious or potentially lethal
airborne agents; uses negative-pressure rooms, HEPA filtration, and
respirators.
◉ Handwashing vs. germicide use. Answer: Mechanical removal of
microbes by scrubbing is more reliable than applying a chemical
alone.
7 2026 FINAL PRACTICE PAPER QUESTIONS
AND ANSWERS
◉ Sanitization. Answer: Substantial reduction of microbial
populations to meet health-related standards.
◉ X-rays (sterilization). Answer: High-energy photons generated by
electrical discharge, employed for surface and package sterilization.
◉ Residual activity. Answer: The continued antimicrobial effect of a
substance after the initial application, useful for prolonged
protection.
◉ Alcohols (ethanol/isopropanol). Answer: Organic solvents that
coagulate proteins and disrupt membranes; fast-acting but
evaporate quickly.
◉ Disinfection-by-products (DBPs). Answer: Potentially harmful
chemicals formed when chlorine reacts with organic matter during
water treatment.
, ◉ Heat-sensitive materials. Answer: Plastics and polymers that can
be damaged by high temperatures, requiring non-thermal control
methods.
◉ Gamma rays. Answer: Electromagnetic radiation emitted from
radioactive isotopes, used for deep penetration sterilization.
◉ Autoclave. Answer: Pressurized steam system that operates at
121 °C and 15 psi for at least 15 minutes to achieve sterility.
◉ Pasteurization. Answer: A short-duration heat treatment that
reduces spoilage organisms and destroys pathogens while
preserving the product's qualities.
◉ Biguanides (chlorhexidine). Answer: Compounds that damage
membranes and inhibit enzymes; persistent on skin but ineffective
against spores.
◉ Biosafety Level 3. Answer: Work with serious or potentially lethal
airborne agents; uses negative-pressure rooms, HEPA filtration, and
respirators.
◉ Handwashing vs. germicide use. Answer: Mechanical removal of
microbes by scrubbing is more reliable than applying a chemical
alone.
