MICROBIOLOGY AND GENETICS EXAM 2025|159 QUESTIONS
WITH ACCURATE SOLUTIONS
1. In a hypothetical scenario where a cell has a mutation that results in the
production of only 10 functional aminoacyl-tRNA synthetase enzymes,
what impact would this have on protein synthesis?
Protein synthesis would be impaired due to the inability to attach
all necessary amino acids to tRNA molecules.
Protein synthesis would proceed normally as there are still enough
enzymes.
Only non-essential proteins would be synthesized effectively.
The cell would switch to using alternative pathways for protein
synthesis.
2. In a laboratory experiment, if a mutation occurs in the sensor kinase of
Bacillus subtilis, what would you expect to happen to the sporulation
process during nutrient deprivation?
Sporulation would be impaired or not occur.
Sporulation would occur more rapidly than normal.
Sporulation would happen under nutrient-rich conditions.
Sporulation would be unaffected.
3. Which of the following pathogens fall under the category of Coccidia
Apicomplexa:
Eimeria and Toxoplasma
Babesia and Cytauxzoon
Giardia and Trichomonads
Trypanosoma and Leishmania
,4. Describe the concept of mixotrophy in microorganisms and its
ecological significance.
Mixotrophy refers to the ability of microorganisms to utilize
both organic and inorganic carbon sources, allowing them to
adapt to varying environmental conditions.
Mixotrophy is the exclusive use of inorganic carbon sources for
energy production.
Mixotrophy involves the absorption of nutrients through osmosis
only.
Mixotrophy is a process exclusive to photosynthetic organisms.
5. A pregnant woman became infected by a protozoa after cleaning the cat
litter box, and the infection crossed the placenta. Her baby was
spontaneously aborted. What organism most likely caused her infection?
Plasmodium falciparum
Naegleria fowleri
Toxoplasma gondii
Trypanosoma cruzi
6. Who were the scientists that provided the first evidence that DNA carries
genetic information?
Avery, MacLeod, and McCarty
Griffith
Watson and Crick
Hershey and Chase
7. Describe the significance of Metchnikoff's discovery regarding
leukocytes and their role in immunity.
, Metchnikoff's discovery of phagocytosis demonstrated that
leukocytes can engulf and destroy pathogens, highlighting their
crucial role in the immune response.
Metchnikoff discovered that leukocytes produce antibodies to
fight infections.
Metchnikoff's work showed that leukocytes are primarily
responsible for nutrient uptake in the bloodstream.
Metchnikoff identified that leukocytes can only recognize viruses,
not bacteria.
8. Which of the following discovered bacteria-engulfing, phagocytic cells in
the blood?
Elie Metchnikoff
Edward Jenner
Charles Chamberland
Joseph Lister
9. The bioluminescence of Vibrio fischeri is regulated by quorum sensing.
When there is a high density of V. fischeri cells, then:
Autoinducers bind to the LuxR protein, which leads to increased
transcription of the lux operon
The bacterial cells activate the production of virulence factors
encoded by the lux operon
There is a high concentration of autoinducers, leading to
repression of the lux operon
The autoinducers activate a TCS, leading to the phosphorylation of
a response regulator
10. What do the terms phototroph and chemotroph specifically describe in
organisms?
, energy
electrons
carbon
nitrogen
11. Alternate forms of genes resulting from mutations in a population of cells
are called ________ _.
isoforms
alterons
alleles
lethal
12. Describe how the chromosome segregation in Sulfolobus compares to
that in bacteria during the cell cycle.
Both Sulfolobus and bacteria segregate their chromosomes in a
similar manner during cell division.
Sulfolobus has a more complex chromosome segregation
mechanism than bacteria.
Bacteria segregate chromosomes using a spindle apparatus,
while Sulfolobus does not.
The chromosome segregation in Sulfolobus occurs only during
G1 phase, unlike in bacteria.
13. An enzyme catalyzes a chemical reaction by:
Increasing the energy of the reaction.
Lowering the energy of the products.
Lowering the activation energy.
Raising the energy of the products.
WITH ACCURATE SOLUTIONS
1. In a hypothetical scenario where a cell has a mutation that results in the
production of only 10 functional aminoacyl-tRNA synthetase enzymes,
what impact would this have on protein synthesis?
Protein synthesis would be impaired due to the inability to attach
all necessary amino acids to tRNA molecules.
Protein synthesis would proceed normally as there are still enough
enzymes.
Only non-essential proteins would be synthesized effectively.
The cell would switch to using alternative pathways for protein
synthesis.
2. In a laboratory experiment, if a mutation occurs in the sensor kinase of
Bacillus subtilis, what would you expect to happen to the sporulation
process during nutrient deprivation?
Sporulation would be impaired or not occur.
Sporulation would occur more rapidly than normal.
Sporulation would happen under nutrient-rich conditions.
Sporulation would be unaffected.
3. Which of the following pathogens fall under the category of Coccidia
Apicomplexa:
Eimeria and Toxoplasma
Babesia and Cytauxzoon
Giardia and Trichomonads
Trypanosoma and Leishmania
,4. Describe the concept of mixotrophy in microorganisms and its
ecological significance.
Mixotrophy refers to the ability of microorganisms to utilize
both organic and inorganic carbon sources, allowing them to
adapt to varying environmental conditions.
Mixotrophy is the exclusive use of inorganic carbon sources for
energy production.
Mixotrophy involves the absorption of nutrients through osmosis
only.
Mixotrophy is a process exclusive to photosynthetic organisms.
5. A pregnant woman became infected by a protozoa after cleaning the cat
litter box, and the infection crossed the placenta. Her baby was
spontaneously aborted. What organism most likely caused her infection?
Plasmodium falciparum
Naegleria fowleri
Toxoplasma gondii
Trypanosoma cruzi
6. Who were the scientists that provided the first evidence that DNA carries
genetic information?
Avery, MacLeod, and McCarty
Griffith
Watson and Crick
Hershey and Chase
7. Describe the significance of Metchnikoff's discovery regarding
leukocytes and their role in immunity.
, Metchnikoff's discovery of phagocytosis demonstrated that
leukocytes can engulf and destroy pathogens, highlighting their
crucial role in the immune response.
Metchnikoff discovered that leukocytes produce antibodies to
fight infections.
Metchnikoff's work showed that leukocytes are primarily
responsible for nutrient uptake in the bloodstream.
Metchnikoff identified that leukocytes can only recognize viruses,
not bacteria.
8. Which of the following discovered bacteria-engulfing, phagocytic cells in
the blood?
Elie Metchnikoff
Edward Jenner
Charles Chamberland
Joseph Lister
9. The bioluminescence of Vibrio fischeri is regulated by quorum sensing.
When there is a high density of V. fischeri cells, then:
Autoinducers bind to the LuxR protein, which leads to increased
transcription of the lux operon
The bacterial cells activate the production of virulence factors
encoded by the lux operon
There is a high concentration of autoinducers, leading to
repression of the lux operon
The autoinducers activate a TCS, leading to the phosphorylation of
a response regulator
10. What do the terms phototroph and chemotroph specifically describe in
organisms?
, energy
electrons
carbon
nitrogen
11. Alternate forms of genes resulting from mutations in a population of cells
are called ________ _.
isoforms
alterons
alleles
lethal
12. Describe how the chromosome segregation in Sulfolobus compares to
that in bacteria during the cell cycle.
Both Sulfolobus and bacteria segregate their chromosomes in a
similar manner during cell division.
Sulfolobus has a more complex chromosome segregation
mechanism than bacteria.
Bacteria segregate chromosomes using a spindle apparatus,
while Sulfolobus does not.
The chromosome segregation in Sulfolobus occurs only during
G1 phase, unlike in bacteria.
13. An enzyme catalyzes a chemical reaction by:
Increasing the energy of the reaction.
Lowering the energy of the products.
Lowering the activation energy.
Raising the energy of the products.
