CBSE Class 11 Microbiology MCQs

CBSE Class 11 Microbiology MCQs: Microbiology is a vital subject in the CBSE Class 11 Biology syllabus, which covers various aspects of microorganisms, their classification, roles, and interactions in different environments. For students preparing for the NEET exam, mastering microbiology concepts is crucial as they form an integral part of the Biology MCQs in the NEET Biology section. These MCQs are designed to test your understanding of the microscopic world, from bacteria and viruses to fungi and algae. The Class 11 Biology curriculum provides a foundation for further learning in microbiology, while NEET Biology MCQs demand in-depth knowledge and application of these concepts in complex problem-solving scenarios. The following MCQs on microbiology are crafted to help you revise and prepare efficiently, ensuring a better grasp of the topic for both CBSE exams and the NEET exam.

Microbiology MCQs

Microbiology is a branch of biology that deals with the study of microorganisms, which include bacteria, viruses, fungi, algae, and protozoa. It focuses on understanding their structure, classification, behavior, interactions, and roles in various ecosystems. Microbiology is an essential topic in Class 11 Biology under the CBSE syllabus. It is covered in topics such as the diversity of microorganisms, their significance in processes like fermentation, and their role in disease causation, both in humans and plants.

Definition of Microbiology: Microbiology is the scientific study of microorganisms, their characteristics, and their interactions with humans, animals, plants, and the environment. This field is crucial for medical science, environmental studies, and biotechnology.

Examples of Microorganisms:

• Bacteria: Escherichia coli (E. coli), which can live in the intestines of humans and other animals.
• Viruses: Influenza virus, which causes flu.
• Fungi: Saccharomyces cerevisiae, used in baking and brewing industries.
• Algae: Chlorella, a single-celled green algae that is used in nutritional supplements.

CBSE Class 11 Microbiology MCQs with Answers

1. Which of the following is not a characteristic of prokaryotic cells?
a) Absence of membrane-bound organelles
b) Presence of a well-defined nucleus
c) Presence of ribosomes
d) Presence of a plasma membrane
Answer: b) Presence of a well-defined nucleus

2. Which microorganism is responsible for tuberculosis?
a) Bacillus anthracis
b) Mycobacterium tuberculosis
c) Escherichia coli
d) Staphylococcus aureus
Answer: b) Mycobacterium tuberculosis

3. Which of the following is the primary role of fungi in an ecosystem?
a) Producers of oxygen
b) Producers of glucose
c) Decomposers of organic matter
d) Symbiotic nitrogen fixers
Answer: c) Decomposers of organic matter

4. In which phase of the bacterial growth curve does the population grow at a constant rate?
a) Lag phase
b) Exponential phase
c) Stationary phase
d) Death phase
Answer: b) Exponential phase

5. Which is the main constituent of the bacterial cell wall in Gram-positive bacteria?
a) Peptidoglycan
b) Lipopolysaccharides
c) Cellulose
d) Chitin
Answer: a) Peptidoglycan

6. Which one of the following is used for the sterilization of surgical instruments?
a) UV light
b) Heat
c) Gamma radiation
d) Boiling water
Answer: b) Heat

7. Which of the following viruses is known for causing the common cold?
a) Influenza virus
b) Rhinovirus
c) Hepatitis virus
d) HIV virus
Answer: b) Rhinovirus

8. What type of symbiotic relationship is formed between Rhizobium and leguminous plants?
a) Parasitism
b) Commensalism
c) Mutualism
d) Predation
Answer: c) Mutualism

9. Which is the mode of transmission of Malaria?
a) Airborne
b) Vector-borne (Anopheles mosquito)
c) Direct contact
d) Contaminated water
Answer: b) Vector-borne (Anopheles mosquito)

10. The process of genetic material exchange between two bacterial cells through direct contact is called:
a) Transformation
b) Transduction
c) Conjugation
d) Binary fission
Answer: c) Conjugation

11. Which of the following is the causative agent of cholera?
a) Salmonella typhi
b) Vibrio cholerae
c) Clostridium tetani
d) Escherichia coli
Answer: b) Vibrio cholerae

12. What is the main function of the bacterial capsule?
a) Protein synthesis
b) Protection against desiccation
c) Protection from phagocytosis
d) DNA replication
Answer: c) Protection from phagocytosis

13. Which of the following is an example of a viral disease?
a) Tuberculosis
b) Hepatitis B
c) Malaria
d) Leprosy
Answer: b) Hepatitis B

14. The process of converting atmospheric nitrogen into a usable form for plants is called:
a) Nitrogen fixation
b) Denitrification
c) Ammonification
d) Nitrification
Answer: a) Nitrogen fixation

15. Which of the following microorganisms is commonly used in the production of yogurt?
a) Aspergillus
b) Saccharomyces
c) Lactobacillus
d) Bacillus
Answer: c) Lactobacillus

16. Which of the following is a characteristic of viruses?
a) Can reproduce on their own
b) Contain both RNA and DNA
c) Cannot reproduce outside a host cell
d) Have a well-defined nucleus
Answer: c) Cannot reproduce outside a host cell

17. Which of the following is used for the identification of bacteria?
a) Gram staining
b) PCR technique
c) Electrophoresis
d) Both a and b
Answer: d) Both a and b

18. Which bacterium is known to fix nitrogen in the root nodules of leguminous plants?
a) Escherichia coli
b) Bacillus subtilis
c) Rhizobium
d) Clostridium
Answer: c) Rhizobium

19. Which of the following is the primary vector for the transmission of the Dengue virus?
a) Anopheles mosquito
b) Culex mosquito
c) Aedes mosquito
d) Tsetse fly
Answer: c) Aedes mosquito

20. Which bacteria are known for their ability to photosynthesize?
a) Cyanobacteria
b) Streptococcus
c) Clostridium
d) Mycobacterium
Answer: a) Cyanobacteria

21. Which of the following is a function of the endospores in bacteria?
a) Reproduction
b) Protection from extreme conditions
c) Respiration
d) Protein synthesis
Answer: b) Protection from extreme conditions

22. What is the main purpose of Koch’s postulates?
a) To determine the method of bacterial reproduction
b) To identify the specific organism causing a disease
c) To study the effects of antibiotics
d) To classify different bacteria
Answer: b) To identify the specific organism causing a disease

23. Which is the largest known virus?
a) T4 bacteriophage
b) Influenza virus
c) Variola virus
d) Mimivirus
Answer: d) Mimivirus

24. Which of the following is NOT a characteristic of viruses?
a) Contain either DNA or RNA
b) Can be crystallized
c) Can reproduce independently
d) Lack cellular structures
Answer: c) Can reproduce independently

25. Which type of bacteria is known to cause food poisoning?
a) Streptococcus
b) Salmonella
c) Lactobacillus
d) Mycobacterium
Answer: b) Salmonella

26. Which of the following is a type of symbiotic relationship between two organisms where one benefits and the other is harmed?
a) Mutualism
b) Commensalism
c) Parasitism
d) Cooperation
Answer: c) Parasitism

27. Which of the following is responsible for antibiotic resistance in bacteria?
a) Gene transfer through conjugation
b) Horizontal gene transfer
c) Mutation
d) All of the above
Answer: d) All of the above

28. Which type of microorganisms are used for the production of alcoholic beverages?
a) Yeasts
b) Bacteria
c) Protozoa
d) Algae
Answer: a) Yeasts

29. Which of the following diseases is caused by a prion?
a) Mad cow disease
b) Tuberculosis
c) Hepatitis
d) Malaria
Answer: a) Mad cow disease

30. Which of the following is an example of a microbial bioremediation process?
a) Nitrogen fixation
b) Oil spill cleanup
c) Carbon fixation
d) Oxygen production
Answer: b) Oil spill cleanup