MIP1502 – Microbiology Assignment 3
(Exam Study Guide 2025/2026)
Questions & Verified Detailed Answers (1–70)
1. Which of the following structures is found in all prokaryotic cells?
A. Nucleus
☑️
B. Mitochondria
C. Ribosomes
D. Chloroplasts
Answer:
All prokaryotic cells contain ribosomes, which are responsible for protein synthesis. Unlike
eukaryotes, they lack membrane-bound organelles such as nuclei, mitochondria, and
chloroplasts. Ribosomes in prokaryotes are 70S in size, distinguishing them from the 80S
ribosomes of eukaryotes.
2. Which scientist is credited with developing pure culture techniques?
☑️
A. Louis Pasteur
B. Robert Koch
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer:
Robert Koch developed pure culture techniques, which allowed scientists to isolate and
grow specific microorganisms. This advancement was critical in linking microbes to particular
diseases, such as Mycobacterium tuberculosis causing tuberculosis.
3. The Gram stain differentiates bacteria based on:
☑️
A. Capsule thickness
B. Cell wall structure
C. Ribosomal size
D. Flagella arrangement
Answer:
Gram staining classifies bacteria into Gram-positive and Gram-negative groups based on
,cell wall composition. Gram-positive bacteria retain crystal violet due to thick peptidoglycan,
while Gram-negative bacteria have thin peptidoglycan and an outer membrane, leading to
pink/red staining after safranin counterstain.
4. Which component of bacterial cell walls is targeted by lysozyme?
A. Peptidoglycan ☑️
B. Lipopolysaccharide
C. Teichoic acid
D. Mycolic acid
Answer:
Lysozyme hydrolyzes the bonds between N-acetylmuramic acid and N-acetylglucosamine in
peptidoglycan. This enzyme, present in tears and saliva, is part of the body’s innate defense
against bacterial infection, especially effective against Gram-positive bacteria.
5. Which microorganism is used in the production of penicillin?
A. Penicillium notatum ☑️
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Rhizopus stolonifer
Answer:
Penicillium notatum produces penicillin, the first widely used antibiotic discovered by
Alexander Fleming in 1928. It revolutionized medicine by providing an effective treatment
against many bacterial infections.
6. Which of the following is an obligate intracellular parasite?
☑️
A. Bacteria
B. Viruses
C. Fungi
D. Protozoa
Answer:
Viruses are obligate intracellular parasites, meaning they cannot reproduce outside a living
host cell. They lack metabolic machinery and must hijack the host’s cellular processes to
replicate.
7. What is the main function of bacterial endospores?
, A. Reproduction
☑️
B. Protein synthesis
C. Survival under harsh conditions
D. Energy storage
Answer:
Endospores, produced by genera such as Bacillus and Clostridium, allow bacteria to survive
extreme heat, desiccation, and radiation. They contain a tough coat and dehydrated
cytoplasm, enabling survival until favorable conditions return.
8. Which of the following is NOT a characteristic of fungi?
A. Eukaryotic
☑️
B. Cell wall contains chitin
C. Photosynthetic
D. Absorptive nutrition
Answer:
Fungi are eukaryotic organisms with chitin cell walls, and they obtain nutrients through
absorption. They are non-photosynthetic and rely on organic material for energy,
distinguishing them from plants.
9. Who is considered the "Father of Microbiology"?
A. Louis Pasteur
☑️
B. Robert Koch
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer:
Antonie van Leeuwenhoek was the first to observe microorganisms using simple
microscopes in the 1600s. His detailed observations laid the foundation for microbiology as a
scientific field.
10. Which process describes bacterial cell division?
☑️
A. Mitosis
B. Binary fission
C. Meiosis
D. Budding
Answer:
Bacteria reproduce primarily through binary fission, a form of asexual reproduction in which
(Exam Study Guide 2025/2026)
Questions & Verified Detailed Answers (1–70)
1. Which of the following structures is found in all prokaryotic cells?
A. Nucleus
☑️
B. Mitochondria
C. Ribosomes
D. Chloroplasts
Answer:
All prokaryotic cells contain ribosomes, which are responsible for protein synthesis. Unlike
eukaryotes, they lack membrane-bound organelles such as nuclei, mitochondria, and
chloroplasts. Ribosomes in prokaryotes are 70S in size, distinguishing them from the 80S
ribosomes of eukaryotes.
2. Which scientist is credited with developing pure culture techniques?
☑️
A. Louis Pasteur
B. Robert Koch
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer:
Robert Koch developed pure culture techniques, which allowed scientists to isolate and
grow specific microorganisms. This advancement was critical in linking microbes to particular
diseases, such as Mycobacterium tuberculosis causing tuberculosis.
3. The Gram stain differentiates bacteria based on:
☑️
A. Capsule thickness
B. Cell wall structure
C. Ribosomal size
D. Flagella arrangement
Answer:
Gram staining classifies bacteria into Gram-positive and Gram-negative groups based on
,cell wall composition. Gram-positive bacteria retain crystal violet due to thick peptidoglycan,
while Gram-negative bacteria have thin peptidoglycan and an outer membrane, leading to
pink/red staining after safranin counterstain.
4. Which component of bacterial cell walls is targeted by lysozyme?
A. Peptidoglycan ☑️
B. Lipopolysaccharide
C. Teichoic acid
D. Mycolic acid
Answer:
Lysozyme hydrolyzes the bonds between N-acetylmuramic acid and N-acetylglucosamine in
peptidoglycan. This enzyme, present in tears and saliva, is part of the body’s innate defense
against bacterial infection, especially effective against Gram-positive bacteria.
5. Which microorganism is used in the production of penicillin?
A. Penicillium notatum ☑️
B. Aspergillus niger
C. Saccharomyces cerevisiae
D. Rhizopus stolonifer
Answer:
Penicillium notatum produces penicillin, the first widely used antibiotic discovered by
Alexander Fleming in 1928. It revolutionized medicine by providing an effective treatment
against many bacterial infections.
6. Which of the following is an obligate intracellular parasite?
☑️
A. Bacteria
B. Viruses
C. Fungi
D. Protozoa
Answer:
Viruses are obligate intracellular parasites, meaning they cannot reproduce outside a living
host cell. They lack metabolic machinery and must hijack the host’s cellular processes to
replicate.
7. What is the main function of bacterial endospores?
, A. Reproduction
☑️
B. Protein synthesis
C. Survival under harsh conditions
D. Energy storage
Answer:
Endospores, produced by genera such as Bacillus and Clostridium, allow bacteria to survive
extreme heat, desiccation, and radiation. They contain a tough coat and dehydrated
cytoplasm, enabling survival until favorable conditions return.
8. Which of the following is NOT a characteristic of fungi?
A. Eukaryotic
☑️
B. Cell wall contains chitin
C. Photosynthetic
D. Absorptive nutrition
Answer:
Fungi are eukaryotic organisms with chitin cell walls, and they obtain nutrients through
absorption. They are non-photosynthetic and rely on organic material for energy,
distinguishing them from plants.
9. Who is considered the "Father of Microbiology"?
A. Louis Pasteur
☑️
B. Robert Koch
C. Antonie van Leeuwenhoek
D. Joseph Lister
Answer:
Antonie van Leeuwenhoek was the first to observe microorganisms using simple
microscopes in the 1600s. His detailed observations laid the foundation for microbiology as a
scientific field.
10. Which process describes bacterial cell division?
☑️
A. Mitosis
B. Binary fission
C. Meiosis
D. Budding
Answer:
Bacteria reproduce primarily through binary fission, a form of asexual reproduction in which
