BIOC17 Lab Exam 2026 Exam Latest!! LATEST
VERSIONS 50 QUESTIONS AND CORRECT
VERIFIED ANSWERS WITH RATIONALES (100%
CORRECT) A+ GRADED ASSURED
Amphitrichous - CORRECT ANSWER: Flagella at both poles of the cell
Ampicllin - CORRECT ANSWER: A β-lactam antibiotic that inhibits transpeptidation by
binding as a competitive inhibitor. Effect against both gram-positive and gram-negative bacteria
Antiseptic - CORRECT ANSWER: A chemical germicide used to kill microbes by application to
living tissues (e.g., hydrogen peroxide)
Auxotrophic strain - CORRECT ANSWER: A mutant strain used in conjugation experiments that
needs a particular supplement for survival (e.g., E. coli J-53R cannot survive unless plated on
media containing methionine and proline
Bacillus stearothermophilus - CORRECT ANSWER: A thermophile bacterium used in the effect
of temperature lab
Bactericidal - CORRECT ANSWER: Kills bacteria (cells in the zone of inhibition are dead)
Bacteriostatic - CORRECT ANSWER: Inhibits bacterial growth or multiplication (cells in the
zone of inhibition are alive)
Capsule stain procedure - CORRECT ANSWER: 1 drop of Congo Red (acidic dye, will exclude
the cells) is mixed with culture on one end of a slide. Another slide is used to push this mixture
across the slide, which is left to dry. The slide is then flooded with Maneval's stain for 60s (basic
dye, will stain the cells). The capsule is left white against the background and cells.
, Chloramphenicol - CORRECT ANSWER: An antibiotic that inhibits the 50S ribosomal subunit
Congo Red - CORRECT ANSWER: An acidic stain that will exclude cells (both negatively
charged)
Decolourizer - CORRECT ANSWER: Often the differential agent in a staining procedure that
will remove stain from one structure/bacteria but not another (e.g., water or ethanol)
Disinfectant - CORRECT ANSWER: A chemical germicide used to kill microbes by application
to a surface (e.g., ethanol, bleach)
Endospore stain procedure - CORRECT ANSWER: Begin with heat-fixed smears. The smears
are covered with blotting paper and flooded with Malachite Green (primary stain) over a boiling
water bath (mordant) for 5 min. The slide is rinsed with water (decolourizer), then covered with
Safranin for 60s (secondary stain)
Escherichia coli HT-99 - CORRECT ANSWER: An E. coli strain used for the conjugation
experiment: a donor cell (F+) with plasmid-encoded chloramphenicol resistance
Escherichia coli J-53R - CORRECT ANSWER: An E. coli strain used for the conjugation
experiment: a recipient cell (F-) with chromosome-encoded rifampicin resistance
Gram stain procedure - CORRECT ANSWER: Begin with heat-fixed smears. The smears are
covered with crystal violet (primary stain) for 60s, then rinsed. The smears are covered with
Gram's iodine (mordant) for 60s, then rinsed. The smears are covered thrice with 95% EtOH
(decolourizer) for 5s, then rinsed. Finally, the smears are covered with Safranin (secondary stain)
for 60s, the slide is rinsed, blotted, and viewed.
Gram-variables pattern - CORRECT ANSWER: A mixed pattern of pink and purple cells,
possibly due to culture age, thickness of the smear, and whether the culture forms an endospore.
VERSIONS 50 QUESTIONS AND CORRECT
VERIFIED ANSWERS WITH RATIONALES (100%
CORRECT) A+ GRADED ASSURED
Amphitrichous - CORRECT ANSWER: Flagella at both poles of the cell
Ampicllin - CORRECT ANSWER: A β-lactam antibiotic that inhibits transpeptidation by
binding as a competitive inhibitor. Effect against both gram-positive and gram-negative bacteria
Antiseptic - CORRECT ANSWER: A chemical germicide used to kill microbes by application to
living tissues (e.g., hydrogen peroxide)
Auxotrophic strain - CORRECT ANSWER: A mutant strain used in conjugation experiments that
needs a particular supplement for survival (e.g., E. coli J-53R cannot survive unless plated on
media containing methionine and proline
Bacillus stearothermophilus - CORRECT ANSWER: A thermophile bacterium used in the effect
of temperature lab
Bactericidal - CORRECT ANSWER: Kills bacteria (cells in the zone of inhibition are dead)
Bacteriostatic - CORRECT ANSWER: Inhibits bacterial growth or multiplication (cells in the
zone of inhibition are alive)
Capsule stain procedure - CORRECT ANSWER: 1 drop of Congo Red (acidic dye, will exclude
the cells) is mixed with culture on one end of a slide. Another slide is used to push this mixture
across the slide, which is left to dry. The slide is then flooded with Maneval's stain for 60s (basic
dye, will stain the cells). The capsule is left white against the background and cells.
, Chloramphenicol - CORRECT ANSWER: An antibiotic that inhibits the 50S ribosomal subunit
Congo Red - CORRECT ANSWER: An acidic stain that will exclude cells (both negatively
charged)
Decolourizer - CORRECT ANSWER: Often the differential agent in a staining procedure that
will remove stain from one structure/bacteria but not another (e.g., water or ethanol)
Disinfectant - CORRECT ANSWER: A chemical germicide used to kill microbes by application
to a surface (e.g., ethanol, bleach)
Endospore stain procedure - CORRECT ANSWER: Begin with heat-fixed smears. The smears
are covered with blotting paper and flooded with Malachite Green (primary stain) over a boiling
water bath (mordant) for 5 min. The slide is rinsed with water (decolourizer), then covered with
Safranin for 60s (secondary stain)
Escherichia coli HT-99 - CORRECT ANSWER: An E. coli strain used for the conjugation
experiment: a donor cell (F+) with plasmid-encoded chloramphenicol resistance
Escherichia coli J-53R - CORRECT ANSWER: An E. coli strain used for the conjugation
experiment: a recipient cell (F-) with chromosome-encoded rifampicin resistance
Gram stain procedure - CORRECT ANSWER: Begin with heat-fixed smears. The smears are
covered with crystal violet (primary stain) for 60s, then rinsed. The smears are covered with
Gram's iodine (mordant) for 60s, then rinsed. The smears are covered thrice with 95% EtOH
(decolourizer) for 5s, then rinsed. Finally, the smears are covered with Safranin (secondary stain)
for 60s, the slide is rinsed, blotted, and viewed.
Gram-variables pattern - CORRECT ANSWER: A mixed pattern of pink and purple cells,
possibly due to culture age, thickness of the smear, and whether the culture forms an endospore.
