Free Biodiversity and Variety of Life MCQs with Answers

2081. The nucleoid is found only in certain species of:

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

Explanation: The nucleoid is the region of cytoplasm where the bacterial genetic material is found. It is present in all bacteria and is important for the organism's survival.

2082. Pili are mainly found on certain species of:

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

Explanation: Pili can be found evenly around the surface of the cell, or localized to one or both of the poles. They are found in Gram-negative bacteria only.

2083. Cyanobacteria resemble photosynthetic eukaryotes because they have:

• A. PS-I
• B. None of these
• C. PS-I and PS-II both
• D. PS-II

Explanation: Cyanobacteria have two photosystems (PSI and PSII), and anoxygenic phototrophs have either PSI or PSII-like photosystems.

2084. Which part of bacteria is most delicate and damage to it can kill the bacteria?

• A. Cell wall
• B. Slime
• C. Capsule
• D. Cell membrane

Explanation: The cell membrane of bacteria is very delicate and any damage to it can kill the bacteria. It regulates functions like the transport of proteins, nutrients, metabolites, etc. It also contains enzymes for respiration. All the other components serve as protective materials that serve to prevent the rupturing of the cell membrane.

2085. Which type of bacteria causes gonorrhoea?

• A. Gram-negative
• B. Gram-positive
• C. None of these
• D. E. coli

Explanation: Neisseria gonorrhoeae, the causative agent of gonorrhoea, is a Gram negative, coffee-bean shaped facultative intracellular diplococcus bacterium, the classical sexually transmitted bacteria.

2086. Cyanobacteria help in nitrogen fixation because they have:

• A. Sodium channels
• B. Heterocysts
• C. Hormogonia
• D. Nitrogenase

Explanation: Cyanobacteria have specialized nitrogen-fixing cells called heterocysts which play a vital role in nitrogen fixation.

2087. Tooth discoloration in children is caused by which antibiotic?

• A. Tetracycline
• B. Streptomycin
• C. Azythromycin
• D. Penicillin

Explanation: Tetracycline antibiotic has been found to cause permanent discoloration of teeth in kids below 8 years.

2088. Bacteria plays an important role in:

• A. Phosphorus Cycle
• B. Nitrogen Cycle
• C. Carbon Cycle
• D. All of the above

Explanation: In nitrogen cycle :Nitrogen-fixing bacteria convert N2 to ammonia Nitrifying bacteria convert ammonia to nitrates and nitrites Denitrifying bacteria release the N2 back to the atmosphere by converting nitrates back to atmospheric nitrogen. In the carbon cycle, bacteria decompose dead organisms and release carbon back to the environment. In the phosphorus cycle, bacteria convert phosphate into the organic form so that it can be utilized by the plants.

2089. E. coli is

• A. Anaerobic
• B. Gram negative
• C. Facultative
• D. All of the above

Explanation: E coli is a gram negative (Stains pink with Gram's stain), facultative and anaerobic microbe.

2090. A bacteria without flagella is called:

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

Explanation: Based on their flagella, bacteria can be classified as follows: Atrichous have no flagella (the suffix 'a' usually implies an absence of something) Monotrichous have one flagellum at one end only ('mono'=one) Lophotrichous have a tuft of flagella at one end ('lopho' = tuft) Bitrichous have one flagellum on each end ('bi'= two) Peritrichous have flagella all over the surface (peri = around) Amphitrichous have a tuft of flagella at both ends