Biology grade 12
Unit 2: Microorganisms
-#challengeoftheweek
#FinalExamchallenge
Final Exam-Level: Microorganisms
1. Which of the following is NOT a characteristic of prokaryotic microorganisms?
A. Lack of a true nucleus
B. Presence of ribosomes
C. Presence of a well-defined Golgi apparatus
D. Reproduction via binary fission
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2. Archaea differ from bacteria because:
A. Archaea lack cell walls
B. Archaea have peptidoglycan in their cell walls
C. Archaea have ether-linked membrane lipids
D. Archaea are eukaryotic
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3. Which type of microorganism is used in the production of antibiotics such as penicillin?
A. Protozoa
B. Bacteria
C. Fungi
D. Archaea
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4. The key characteristic that allows bacterial endospores to survive extreme conditions is:
A. High metabolic activity
B. High water content
C. Presence of dipicolinic acid
D. Absence of DNA
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5. Which microorganism is primarily responsible for nitrogen fixation in the soil?
A. Rhizobium
B. Bacillus subtilis
C. Saccharomyces cerevisiae
D. Mycobacterium tuberculosis
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6. What is the primary difference between gram-positive and gram-negative bacteria?
A. Thickness of the peptidoglycan layer
B. Shape of the bacteria
C. Ability to form endospores
D. Presence of a nucleus
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7. The term "microbiota" refers to:
A. All microorganisms in a given environment
B. Pathogenic microorganisms
C. Viruses infecting bacteria
D. Microorganisms causing food spoilage
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8. How do obligate anaerobes differ from facultative anaerobes?
A. Obligate anaerobes require oxygen for survival
B. Obligate anaerobes cannot survive in the presence of oxygen
C. Facultative anaerobes cannot ferment glucose
D. Facultative anaerobes are found only in soil
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9. Which of the following is a major structural component of fungal cell walls?
A. Peptidoglycan
B. Chitin
C. Cellulose
D. Lignin
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10. Viruses differ from all other microorganisms because they:
A. Contain both DNA and RNA
B. Lack cellular structures like ribosomes and cytoplasm
C. Are capable of independent replication
D. Can metabolize nutrients
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11. The most significant role of cyanobacteria in ecosystems is:
A. Decomposition
B. Photosynthesis and oxygen production
C. Causing diseases in plants
D. Symbiotic nitrogen fixation
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12. The term "mycorrhizae" refers to:
A. A pathogenic bacterium
B. Symbiotic relationships between fungi and plant roots
C. A species of photosynthetic algae
D. A structure found in fungal spores
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13. Which of the following methods is most commonly used to sterilize heat-sensitive materials?
A. Autoclaving
B. Dry heat sterilization
C. Filtration
D. UV radiation
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14. In microbiology, "generation time" refers to:
A. The time required for a microbial population to double in number
B. The lifespan of a bacterial cell
C. The time needed for DNA replication
D. The duration of spore germination
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15. Which of the following best describes plasmids in bacteria?
A. Extrachromosomal DNA that replicates independently
B. A single, circular chromosome
C. Sites for protein synthesis
D. Components of the bacterial cell wall
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Answers
1. C
2. C
3. C
4. C
5. A
6. A
7. A
8. B
9. B
10. B
11. B
12. B
13. C
14. A
15. A
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