Free Biodiversity and Variety of Life MCQs with Answers

2311. Which option is CORRECT about endospore?

• A. Has a short dormant period
• B. Contains moisture for survival
• C. Metabolically active
• D. Endures extreme condition

Explanation: Endospores are incredibly resilient to extreme environmental conditions, including high temperatures, desiccation, radiation, and chemical disinfectants. This resistance is due to their tough outer layers.

2312. Bacteria divide at exponential rate during which growth phase!

• A. Lag
• B. Log
• C. Stationary
• D. Decline

Explanation: In this phase, bacteria divide rapidly by binary fission, where each cell splits into two identical daughter cells. The population grows exponentially, doubling at a constant rate. This is the period of maximum growth and optimal conditions for cell division.

2313. Which one of the following organelles is ONLY present in Cyanobacteria?

• A. Heterocyst
• B. Lysosomes
• C. Mitochondria
• D. Ribosomes

Explanation: Heterocysts are specialized cells found in certain filamentous cyanobacteria (blue-green algae) that play a critical role in nitrogen fixation.

2314. Which one of the following is anaerobic bacterium?

• A. Campylobacter
• B. E. coli
• C. Pseudomonas
• D. Spirochete

Explanation: Spirochetes are often anaerobic (or microaerophilic) because of the way their metabolism and cellular structure are adapted to survive.Many spirochetes (e.g., Treponema, Borrelia, Leptospira) are adapted to environments low in oxygen, such as:Deep tissuesMuddy or waterlogged soilIntestines of animalsOral cavities and dental plaquesBecause of this, they evolved to survive without needing oxygen, or needing very little.

2315. Which one of the following is NOT the bacteria?

• A. Acanthurus nigrofuscus
• B. Epulopiscium fishelsoni
• C. Hyphomicrobium
• D. Mycoplasma Spp

Explanation: Acanthurus nigrofuscus, commonly known as the bristletooth tang or brown surgeonfish, is a species of fish belonging to the family Acanthuridae., commonly known as the bristletooth tang or brown surgeonfish, is a species of fish belonging to the family Acanthuridae.

2316. Which one of the following group of chemicals are used to kill or inhibit the growth of microorganisms in living tissues?

• A. Antiseptics
• B. Chemotherapeutics
• C. Disinfectants
• D. Vaccines

Explanation: Antiseptics are chemical substances that inhibit the growth of or destroy microorganisms on living tissues, such as skin and mucous membranes. They are commonly used in medical and personal care settings to prevent infections and promote healing.

2317. The peptidoglycan cell wall is specific to:

• A. Amoeba
• B. Bacteria
• C. Protozoa
• D. Virus

Explanation: Peptidoglycan is a complex polymer found in the cell walls of bacteria. It provides structural strength, rigidity, and shape to the cell wall and protects the cell from osmotic lysis. Peptidoglycan is composed of sugar chains cross-linked by short peptide chains, forming a strong, mesh-like structure. This structure is crucial for bacterial survival, especially in Gram-positive bacteria, where peptidoglycan is particularly thick.

2318. Which of the following is NOT true about plasmids found in Streptococcus?

• A. Carry fewer genes than the chromosome
• B. Replicate autonomously from the chromosome
• C. They are considered as genetic elements
• D. The bacterial chromosome depends on plasmids for replication

Explanation: Actually, the bacterial chromosome does not depend on plasmids for replication. Bacterial chromosomes replicate independently, using their own origin of replication. Plasmids can replicate autonomously but are separate from the main chromosomal DNA. While plasmids can carry genes that may assist with replication or other functions, the chromosome's replication process is not reliant on plasmids.

2319. Which of the following bacteria produces endospores?

• A. Both gram-negative and positive bacteria
• B. Gram-negative
• C. Gram-positive
• D. Mycobacteria

Explanation: Many Gram-positive bacilli (rod-shaped bacteria), such as Bacillus and Clostridium species, can form endospores, which are highly resistant structures that protect the bacterial DNA during unfavorable conditions (e.g., heat, desiccation, and chemicals).

2320. _ is used in the production of Humulin.

• A. Fungi
• B. Bacteria
• C. Protozoa
• D. Virus

Explanation: Bacteria, specifically Escherichia coli, are used in the production of Humulin (human insulin) through genetic engineering.