Free Biodiversity and Variety of Life MCQs with Answers

2331. The cytoplasmic matrix is the substance present between the plasma membrane and the nucleoid. The plasma membrane and everything present within it is termed as:

• A. Plasmid
• B. Mesosomes
• C. Protoplast
• D. Chromatin body

Explanation: In bacterial cell biology, the term "protoplast" is used to describe the entire cell minus the cell wall. It is often used when referring to Gram-negative bacteria or when the cell wall has been removed. The protoplast includes the plasma membrane, cytoplasm, nucleoid (genetic material), and all other cellular components within the plasma membrane.

2332. As we know certain species of bacteria produce spores, these all are the characterstics of a spore except:

• A. Spores can be outside the vegatitive cells
• B. Spores are resistant to adverse environment
• C. Spores may be within the vegetative cells
• D. Spores can never germinate and form vegetative cells

Explanation: Bacterial spores, often referred to as endospores, are a specialized form of reproductive structure formed by certain types of bacteria, primarily within the genera Bacillus and Clostridium. Bacterial spores are highly resistant to adverse environmental conditions, such as heat, desiccation, and radiation. They allow the bacterium to survive in a dormant state until more favorable conditions arise. When conditions become favorable, bacterial spores can germinate, and the spore reverts to its vegetative, actively growing form.

2333. If we say that bacteria become dormant, thick-walled, and desiccation resistant during differentiation of vegetative cells which can germinate under suitable conditions. Which structure we are talking about?

• A. Granules
• B. Ribosomes
• C. Cysts
• D. Nucleoid

Explanation: Cysts are protective structures formed by various microorganisms, including some bacteria and protozoa, to help them survive unfavorable environmental conditions. These cysts are typically dormant or resting stages that are more resistant to external stresses and provide a means for the microorganism to wait until conditions improve.

2334. In Cyanobacteria, All these structures are present except:

• A. Glycogen
• B. Akinetes
• C. Phycobilins
• D. Jelly like mass with numerous filaments

Explanation: Cyanobacteria are a group of photosynthetic bacteria that possess various structures and forms. Some common structures found in cyanobacteria include: Filaments: Cyanobacteria often form filamentous structures, where individual cells are connected in a chain-like arrangement. These filaments can be unicellular or multicellular. Unicellular Forms: Some cyanobacteria exist as individual cells or colonies of cells that do not form filaments. Heterocysts: Certain cyanobacteria possess specialized cells called heterocysts. Heterocysts are involved in nitrogen fixation, converting atmospheric nitrogen into a form that can be utilized by the organism. Sheaths: Cyanobacteria may secrete protective sheaths around their filaments. These sheaths provide structural support and protection. However, a "jelly-like mass" is not a typical characteristic of cyanobacteria. Cyanobacteria are primarily characterized by their filamentous or unicellular forms, along with the presence of specialized structures like heterocysts and sheaths.

2335. It is usually found in bacteria:

• A. Cell wall
• B. Slime
• C. Chromatin bodies
• D. Mesosome

Explanation: The correct option is D) Mesosome. Mesosomes are usually found in bacteria. They are invaginations or infoldings of the plasma membrane, which are associated with various cellular processes, such as cell division and respiration.

2336. Misuse of tetracycline and its related compounds cause:

• A. Deafness
• B. Death
• C. Allergic reactions
• D. Discoloration of teeth in young children

Explanation: Misuse of tetracycline and its related compounds can lead to the discoloration of teeth in young children. Tetracycline can bind to developing teeth and cause permanent yellow-brown discoloration.Tetracyclines can have side effects, especially when used inappropriately or without a healthcare provider's guidance. Common side effects include gastrointestinal issues, photosensitivity (increased sensitivity to sunlight), and potential effects on developing teeth and bones in children and fetuses.

2337. When cocci are arranged irregularly, like clusters of grapes, the arrangement is called:

• A. Streptococcus
• B. Sarcina
• C. Tetracoccus
• D. Staphylococcus

Explanation: When cocci are arranged irregularly, like clusters of grapes, the arrangement is called Staphylococcus. The term "staphylococcus" comes from the Greek words "staphyle" (meaning "grape") and "coccus" (meaning "berry" or "coccus"), which accurately describes the cluster-like appearance of the bacteria.

2338. These are rod-shaped bacteria:

• A. Cocci
• B. Vibrio
• C. Bacilli
• D. Spirochaete

Explanation: Bacilli is plural of bacillus which means rod shaped bacterium. Rod-shaped bacteria, also known as bacilli (singular: bacillus), are a common bacterial morphology characterized by elongated and cylindrical cell shapes. They are one of the three main bacterial cell shapes, along with cocci (spherical) and spirilla (spiral). Bacilli can vary in length.

2339. When rod-shaped bacteria occur in pairs then the arrangement of cells is known as?

• A. Diplobacillus
• B. Bacillus
• C. Streptobacillus
• D. Staphylobacillus

Explanation: It is a consequence of single division and daughter cells remain attached after division. When rod-shaped bacteria occur in pairs, the arrangement of cells is known as "diplobacilli." In this arrangement, two rod-shaped bacterial cells are arranged side by side, forming a pair or diplo configuration. Diplobacilli are a specific type of bacterial cell arrangement and can be a characteristic feature used in the identification and classification of bacteria. The term "diplo" is derived from the Greek word "diploos," meaning double or twofold.

2340. Spirals come in one of the three forms which are:

• A. Vibrio, curved or comma-shaped
• B. Spirochaete, curved or comma-shaped
• C. Spirillum, curved or comma-shaped
• D. Vibrio, Spirillum or Spirochaete shaped

Explanation: Spiral-shaped bacteria exist in three forms which are spirally coiled bacteria: Vibrio is a comma-shaped or curved bacterium. Spirillum is a helical bacterium with thin and flexible walls Spirochete is a helical bacterium with thick and rigid walls.