Free Kingdom Prokaryotae MCQs with Answers

511. The division of cocci in three planes form Sarcina, which is a cube of _ Cocci?

• A. 02
• B. 04
• C. 08
• D. 16

Explanation: Sarcina is a genus of bacteria that divides in three planes, resulting in the formation of packets of cells arranged in a cube-like structure. These packets, known as tetrads, consist of eight cells arranged in a 3-dimensional cubic configuration. Each of the three planes of division produces four daughter cells, resulting in a total of eight cells in the sarcina packet. Therefore, the cube of cells formed by the division of cocci in three planes is composed of eight individual cells.

512. Helicobacter pylori is an example of:

• A. Cocci
• B. Bacilli
• C. Pleomorphic
• D. Spiral

Explanation: Helicobacter pylori exists as both a helix-shaped form (classified as a curved rod) and a coccoid form. Hence, it is classified as a pleomorphic bacterium.

513. Bacteria reproduce asexually by:

• A. Mitosis
• B. Meioses
• C. Conjugation
• D. Fission

Explanation: Bacteria reproduce primarily by binary fission, an asexual process whereby a single cell divides into two. Under ideal conditions some bacterial species may divide every 10-15 minutes-a doubling of the population at these time intervals.

514. The simplest oxygen-producing organisms are:

• A. Photosynthetic bacteria
• B. Autotrophic bacteria
• C. Cyanobacteria
• D. Chlamydomenas

Explanation: Cyanobacteria, also known as blue-green algae, are the simplest oxygen-producing organisms. They are a group of photosynthetic bacteria that are capable of carrying out oxygenic photosynthesis.

515. Salmonella typhosa is a

• A. Coccus bacterium
• B. Bacillus bacterium
• C. Spirillus bacterium
• D. Nitrobacterium

Explanation: Salmonella typhosa is the scientific name for the bacillus bacterium responsible for causing typhoid fever, a severe and potentially life-threatening illness. It belongs to the genus Salmonella, which comprises gram-negative bacteria that are rod-shaped or bacillus.

516. A bacterium that converts NO2 to NO3 is:

• A. Rhizobium
• B. Bacillus
• C. Nitrosomonas
• D. Nitrobacter

Explanation: Nitrobacter is the correct answer because it is involved in the second step of nitrification, where it converts nitrite (NO2) to nitrate (NO3). This is an essential step in the nitrogen cycle, making nitrogen available to plants in a more accessible form. Rhizobium is involved in nitrogen fixation, Bacillus is known for endospore production, and Nitrosomonas converts ammonia to nitrite, not nitrite to nitrate.

517. Pigeon odour is released from the water bloom of:

• A. Slime mold
• B. Water mold
• C. Cyanobacteria
• D. Cyanobacteria Algae ponds

Explanation: The correct answer is Cyanobacteria Algae ponds. Cyanobacteria, often called blue-green algae, can form dense blooms in water, releasing odors due to the organic compounds they produce. These blooms can make the water smell unpleasant and affect its quality. Slime molds and water molds, while they exist in moist environments, do not typically contribute to offensive odors in water bodies. Cyanobacteria, due to their ability to proliferate rapidly in nutrient-rich waters, are the main culprits behind such issues.

518. Bacteria maintain their survival by the formation of:

• A. Hormogonia
• B. Akinetes
• C. Endospores
• D. Zygospores

Explanation: Endospores are the correct answer because they are specialized, durable structures that allow bacteria to survive in unfavorable conditions. Unlike akinets or hormogonia, endospores can withstand extreme environmental stresses such as heat, desiccation, and chemicals. Zygospores, on the other hand, are related to fungi and protists and are not relevant to bacterial survival.

519. When the entire body of a bacterium is covered by flagella, such a bacterium is called:

• A. Atrichous
• B. Lophotrichous
• C. Amphitrichous
• D. Peritrichous

Explanation: Bacteria are classified based on the arrangement of their flagella, which affects their motility. Peritrichous bacteria have flagella all over their surface, enabling them to move in various directions efficiently. This is in contrast to atrichous bacteria, which lack flagella entirely and are non-motile. Lophotrichous and amphitrichous bacteria have flagella localized to specific areas, either in bundles at one end or at both ends, respectively. Thus, the correct answer is D: Peritrichous.

520. Blue green algae, besides chlorophyll also possess another pigment known as:

• A. Phycocyanin
• B. Phycoerythrin
• C. Phycobillirubin
• D. Phycobilliprotein

Explanation: The microbes also contain the same chlorophyll a compound used by plants. Some blue-green algae possess a different photosynthetic pigment, which is known as phycoerythrin.