Free Kingdom Prokaryotae MCQs with Answers

221. Who discovered the bacteria causing tuberculosis and also developed various techniques of media preparation and maintenance of pure culture?

• A. Robert Koch
• B. Louis Pasteur
• C. Alexander Fleming
• D. Antonie van Leeuwenhoek

Explanation: Historical Perspectives Centennial: Koch's Discovery of the Tubercle Bacillus. On March 24, 1882, Robert Koch announced to the Berlin Physiological Society that he had discovered the cause of tuberculosis. Three weeks later, on April 10, he published an article entitled "The Etiology of Tuberculosis".

222. Which of the following is true about both bacterial conjugation and meiosis?

• A. Both processes produce four haploid cells
• B. Both processes are a form of asexual reproduction
• C. Both processes involve genetic recombination
• D. None of these options are correct

Explanation: Both bacterial conjugation and meiosis involve genetic recombination, which is the process of exchanging genetic material to create diversity. In meiosis, genetic recombination occurs during crossing over in prophase I, resulting in four genetically unique haploid cells. In bacterial conjugation, DNA is transferred from a donor to a recipient cell, introducing new genetic material, but it does not result in the production of new cells. Thus, option C is correct. Option A is incorrect because only meiosis produces four haploid cells. Option B is incorrect because both processes are linked to sexual reproduction due to their involvement in genetic recombination. Option D is incorrect because option C is a true statement.

223. What is the method of asexual reproduction?

• A. Sporulation
• B. Fission
• C. Apomixis
• D. All of these options are correct

Explanation: All of the above given options are different mode of sexual reproduction in living beings. Binary fission, multiple fission (animal like protoctists) budding (Hydra) parthenogenesis, tissue culturing, cloning and identical twins are the common asexual methods of reproduction.

224. An example of a bacteria requiring low concentration of oxygen is?

• A. Spirochete
• B. Escherichia coli (E. coli)
• C. Pseudomonas
• D. Campylobacter

Explanation: Option D: Campylobacter is the correct answer as it is a microaerophilic bacterium, requiring low levels of oxygen to survive and grow. This characteristic distinguishes it from the other options. Option A: Spirochetes can survive in a range of oxygen levels and are not exclusively microaerophilic. Option B: E. coli is a facultative anaerobe, adaptable to both oxygen-rich and oxygen-poor environments. Option C: Pseudomonas are versatile in their oxygen requirements and are not limited to low-oxygen conditions.

225. Which of the following is basic function of bacterial slime capsule?

• A. Protection from enviroment
• B. Protection from engulfment
• C. Protection from osmotic lysis
• D. All of the above

Explanation: Capsule is tightly bound to the bacterial cell. It is a part of the cell envelope. It protects cells from engulfment by Eukaryotic cells such as macrophages and it also protects the cells from pathogenicity. Hence option B is correct.Option A and C is incorrect because the cell wall of bacteria protects the cell against osmotic lysis and against environment.

226. The Gram-positive bacteria appear in which color under gram staining?

• A. Purple
• B. Red
• C. Pink
• D. Blue

Explanation: Gram-positive bacteria appear purple under Gram staining because they retain the crystal violet stain due to their thick peptidoglycan layer, which forms a stable crystal violet-iodine complex. During the decolorization step, this complex is not washed out, allowing the bacteria to retain the purple color. In contrast, Gram-negative bacteria have a thinner peptidoglycan layer and a higher lipid content in their cell walls, causing them to lose the crystal violet-iodine complex during the decolorization step and subsequently take up the red or pink safranin counterstain. Therefore, Gram-negative bacteria appear red or pink, not purple.

227. Chemical substances used on living tissues that inhibit the growth of microorganism are called?

• A. Disinfectant
• B. Sanitizer
• C. Antibiotic
• D. Antiseptics

Explanation: Antiseptics are specifically designed for use on living tissues to inhibit or kill microorganisms, making them the correct answer. Disinfectants are meant for non-living surfaces, sanitizers are used to reduce microbes to safe levels on surfaces, and antibiotics are used internally to treat infections, not applied to tissue surfaces.

228. Methanopyrus kandleri is an organism that lives in a hydrogen-carbon dioxide environment and was first discovered in a hydrothermal vent where temperatures reached 230°F. What sort of organism is this?

• A. Protist
• B. Cyanobacteria
• C. Archaea
• D. Bacteria

Explanation: Methanopyrus kandleri is classified as an archaeon because it thrives in extreme environments, such as hydrothermal vents, where temperatures and chemical conditions are extreme. Archaea are known for their ability to survive in such harsh conditions. Protists, being eukaryotic, are not suited to such environments. Cyanobacteria are photosynthetic and not adapted to high-temperature environments like hydrothermal vents. Bacteria, although diverse, do not encompass Methanopyrus kandleri, which is specifically categorized under Archaea due to its unique characteristics and environmental adaptations.

229. The flagella originate from which part of the cell?

• A. Basal body
• B. Cell membrane
• C. Cell wall
• D. Capsule

Explanation: In prokaryotic cells, the flagella originate from the basal body, which is embedded in the cytoplasm and serves as the anchoring point for the flagellum. This structure is responsible for the rotation and movement of the flagella, aiding in cell motility. The basal body has a similar structural arrangement to centrioles, featuring microtubule triplets. The cell membrane, cell wall, and capsule, while important for cellular integrity and protection, do not serve as the origin of the flagella.

230. The presence of which of these cell structures would confirm that the cell is prokaryotic?

• A. Cytoplasm
• B. Ribosomes
• C. Flagella
• D. Peptidoglycan cell wall

Explanation: The presence of a peptidoglycan cell wall is a unique characteristic of most prokaryotic cells, distinguishing them from eukaryotic cells, which do not have peptidoglycan. This rigid layer provides structural support and protection, making it a strong indicator of prokaryotic cells. In contrast, cytoplasm, ribosomes, and flagella are found in both prokaryotic and eukaryotic cells, and thus their presence cannot confirm that a cell is prokaryotic.