MICROBIOLOGY FINAL BRCC ACTUAL
EXAM PAPER 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ True motility.
Answer: Caused by bacterial structures (cilia, flagellum, pseudopodia
(amaeboids)). Whole bacterium moves. Purposeful and directional
swimming movement.
◍ Ways microbes affect our lives.
Answer: Microbes impact health (disease), environment (nutrient cycling),
food production, biotechnology, and medicine
◍ Symbiosis.
Answer: Close relationship between two different organisms living together
◍ Brownian motion.
Answer: Caused by water molecules bouncing off of bacteria;
jiggling/bouncing effect. Erratic vibration of a particle caused by the
unequal collision of water molecules against it.
◍ Parasitism.
Answer: One organism benefits while the other is harmed
◍ Mutualism.
Answer: Both organisms benefit
◍ Streaming.
Answer: All of the objects "flow" with the movement of the water. All
organisms flow in one direction. Caused by difference in water pressure.
◍ Commensalism.
Answer: One benefits, the other is unaffected
,◍ Beneficial uses of microorganisms.
Answer: Food production, antibiotics, decomposition, nitrogen fixation,
biotechnology
◍ Parfocal.
Answer: Microscope that remains in the same plane of field. Only need to
adjust the fine focus knob.
◍ Three domains of life.
Answer: Bacteria, Archaea, Eukarya
◍ Cocci/coccus.
Answer: Sphere-shaped bacterium.
◍ Prokaryotes vs Eukaryotes.
Answer: Prokaryotes lack nucleus and membrane-bound organelles;
eukaryotes have both
◍ Bacilli/bacillus.
Answer: Rod-shaped bacterium.
◍ Spirila/spirilum.
Answer: Spiral/comma-shaped bacterium.
◍ Coarse adjustment knob.
Answer: Used for focusing the specimen. Either moves the stage up or
down. Only use on 4x because you don't want to crash the slide through the
objective lenses (Like I did). Bigger knob.
◍ Fine adjustment knob.
Answer: Fine-tune focuses specimen after using the coarse adj. knob.
Smaller knob.
◍ Iris diaphragm.
Answer: Used to regulate amount of light admitted into microscope. Used to
vary intensity and size of the cone of light that is projected upward onto the
slide.
,◍ Condenser.
Answer: Focuses light onto the specimen.
◍ Objective lenses.
Answer: Light passes through the specimen and then up through these
lenses. Scanning, low power, high-dry, oil immersion.
◍ Major groups in microbiology.
Answer: Bacteria, Archaea, Fungi, Protozoa, Algae, Viruses, Helminths
◍ Causes of death pre-1900s vs 1997.
Answer: Pre-1900s: infectious diseases; 1997: chronic diseases (heart
disease, cancer)
◍ Spontaneous generation.
Answer: Life arises from non-living matter
◍ Biogenesis.
Answer: Life arises from existing life
◍ Ocular lenses.
Answer: 10x. Final magnification achieved here.
◍ Ancient disease theories.
Answer: Supernatural causes, imbalance of humors, miasma (bad air)
◍ Koch's postulates.
Answer: Microbe present in disease, isolated, causes disease, re-isolated
◍ Simple stain.
Answer: Use one reagent that usually stains all bacteria same way. Stains the
cell itself (direct stain).
◍ Emerging infectious diseases.
Answer: New or increasing diseases due to mutation, travel, environment
◍ Direct stain.
Answer: Stains the cell itself. Most have a positive charge at normal pH
levels. Stain molecules tend to stick to the negatively charged bacteria.
, ◍ Metric units for microbes.
Answer: Micrometers (µm), nanometers (nm)
◍ Negative stain.
Answer: Staining the surroundings rather than the bacterium. Have a
negative charge at normal pH levels. Repelled from the bacteria and only
stain the background.
◍ Electromagnetic radiation (EMR).
Answer: Waves of energy used in microscopy (visible light, UV)
◍ Differential stain.
Answer: Multiple reagents used to which different bacteria react differently.
Example is the Gram stain and an acid-fast stain.
◍ Gram stain.
Answer: ALWAYS CAPITALIZE GRAM. Depends on fact that most
bacteria have one of two cell wall compositions. Crystal violet is PRIMARY
stain. All bacteria are stained purple. Gram's iodine, the mordant, combines
with crystal violet and helps hold it to the Gram (+) cell wall. All bacteria
still purple. Next ethanol, the decolorizing agent, is applied. Most important
step because bacteria begin to react differently here. Gram + not easily
decolorized, and remain blue. Gram - easily decolorize and are colorless
here. The counterstain, Safranin, is now added. This is to see the decolorized
Gram - cells. Therefore Gram + are purple and Gram - are red.
◍ Heat-fix.
Answer: Passing the slide through a direct flame. Allows cells to stick to the
slide, become stuck to the slide. Preserves their original cell arrangement.
Keeps them from being washed away during staining.
◍ Light microscope parts.
Answer: Ocular lens, objective lens, stage, condenser, light source
◍ Light path in microscope.
Answer: Light → condenser → specimen → objective → ocular → eye
EXAM PAPER 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ True motility.
Answer: Caused by bacterial structures (cilia, flagellum, pseudopodia
(amaeboids)). Whole bacterium moves. Purposeful and directional
swimming movement.
◍ Ways microbes affect our lives.
Answer: Microbes impact health (disease), environment (nutrient cycling),
food production, biotechnology, and medicine
◍ Symbiosis.
Answer: Close relationship between two different organisms living together
◍ Brownian motion.
Answer: Caused by water molecules bouncing off of bacteria;
jiggling/bouncing effect. Erratic vibration of a particle caused by the
unequal collision of water molecules against it.
◍ Parasitism.
Answer: One organism benefits while the other is harmed
◍ Mutualism.
Answer: Both organisms benefit
◍ Streaming.
Answer: All of the objects "flow" with the movement of the water. All
organisms flow in one direction. Caused by difference in water pressure.
◍ Commensalism.
Answer: One benefits, the other is unaffected
,◍ Beneficial uses of microorganisms.
Answer: Food production, antibiotics, decomposition, nitrogen fixation,
biotechnology
◍ Parfocal.
Answer: Microscope that remains in the same plane of field. Only need to
adjust the fine focus knob.
◍ Three domains of life.
Answer: Bacteria, Archaea, Eukarya
◍ Cocci/coccus.
Answer: Sphere-shaped bacterium.
◍ Prokaryotes vs Eukaryotes.
Answer: Prokaryotes lack nucleus and membrane-bound organelles;
eukaryotes have both
◍ Bacilli/bacillus.
Answer: Rod-shaped bacterium.
◍ Spirila/spirilum.
Answer: Spiral/comma-shaped bacterium.
◍ Coarse adjustment knob.
Answer: Used for focusing the specimen. Either moves the stage up or
down. Only use on 4x because you don't want to crash the slide through the
objective lenses (Like I did). Bigger knob.
◍ Fine adjustment knob.
Answer: Fine-tune focuses specimen after using the coarse adj. knob.
Smaller knob.
◍ Iris diaphragm.
Answer: Used to regulate amount of light admitted into microscope. Used to
vary intensity and size of the cone of light that is projected upward onto the
slide.
,◍ Condenser.
Answer: Focuses light onto the specimen.
◍ Objective lenses.
Answer: Light passes through the specimen and then up through these
lenses. Scanning, low power, high-dry, oil immersion.
◍ Major groups in microbiology.
Answer: Bacteria, Archaea, Fungi, Protozoa, Algae, Viruses, Helminths
◍ Causes of death pre-1900s vs 1997.
Answer: Pre-1900s: infectious diseases; 1997: chronic diseases (heart
disease, cancer)
◍ Spontaneous generation.
Answer: Life arises from non-living matter
◍ Biogenesis.
Answer: Life arises from existing life
◍ Ocular lenses.
Answer: 10x. Final magnification achieved here.
◍ Ancient disease theories.
Answer: Supernatural causes, imbalance of humors, miasma (bad air)
◍ Koch's postulates.
Answer: Microbe present in disease, isolated, causes disease, re-isolated
◍ Simple stain.
Answer: Use one reagent that usually stains all bacteria same way. Stains the
cell itself (direct stain).
◍ Emerging infectious diseases.
Answer: New or increasing diseases due to mutation, travel, environment
◍ Direct stain.
Answer: Stains the cell itself. Most have a positive charge at normal pH
levels. Stain molecules tend to stick to the negatively charged bacteria.
, ◍ Metric units for microbes.
Answer: Micrometers (µm), nanometers (nm)
◍ Negative stain.
Answer: Staining the surroundings rather than the bacterium. Have a
negative charge at normal pH levels. Repelled from the bacteria and only
stain the background.
◍ Electromagnetic radiation (EMR).
Answer: Waves of energy used in microscopy (visible light, UV)
◍ Differential stain.
Answer: Multiple reagents used to which different bacteria react differently.
Example is the Gram stain and an acid-fast stain.
◍ Gram stain.
Answer: ALWAYS CAPITALIZE GRAM. Depends on fact that most
bacteria have one of two cell wall compositions. Crystal violet is PRIMARY
stain. All bacteria are stained purple. Gram's iodine, the mordant, combines
with crystal violet and helps hold it to the Gram (+) cell wall. All bacteria
still purple. Next ethanol, the decolorizing agent, is applied. Most important
step because bacteria begin to react differently here. Gram + not easily
decolorized, and remain blue. Gram - easily decolorize and are colorless
here. The counterstain, Safranin, is now added. This is to see the decolorized
Gram - cells. Therefore Gram + are purple and Gram - are red.
◍ Heat-fix.
Answer: Passing the slide through a direct flame. Allows cells to stick to the
slide, become stuck to the slide. Preserves their original cell arrangement.
Keeps them from being washed away during staining.
◍ Light microscope parts.
Answer: Ocular lens, objective lens, stage, condenser, light source
◍ Light path in microscope.
Answer: Light → condenser → specimen → objective → ocular → eye
