Free Biodiversity and Variety of Life MCQs with Answers

2101. What is the structure in prokaryotic cells that often holds antibiotic resistance genes?

• A. Nucleus
• B. Plasmid
• C. Mitochondria
• D. Both Options A and B are correct

Explanation: Prokaryotes can also contain plasmids, which are much smaller circular pieces of DNA that often have genes that give antibiotic resistance.OPTION A: Prokaryotes have no nucleus they have nuclear material dispersed in their cytoplasm.OPTION B: Prokaryotes can also contain plasmids, which are much smaller circular pieces of DNA that often have genes that give antibiotic resistance.OPTION C: Prokaryotes lack mitochondria and instead produce their ATP on their cell surface membrane.OPTION D: As only option B is correct hence A and B cannot be correct.

2102. Which of the following is true regarding the bacteria?

• A. Bacteria contain plasma membranes that are made up of triglycerides
• B. Gram staining reveals that bacteria contain cell walls, but no cell membranes
• C. Bacteria do not contain a membrane-bound nucleus, but they contain an non membrane-bound structure called the nucleoid
• D. All of these options are false

Explanation: Option A; All cells including bactria contain cell membrane but it is not made up of triglycerides.Option B: Gram staining tells us about the nature of cell wall gram positive and gram negative bacteria .It does not tell about cell membrane.Option C: Bacteria do not contain membrane-bound organelles such as mitochondria or chloroplasts, as eukaryotes do. However, photosynthetic bacteria, such as cyanobacteria, may be filled with tightly packed folds of their outer

2103. Which of the following is found in bacterial cells, but not in mature red blood cells?

• A. Nucleus
• B. DNA
• C. Cell membrane
• D. Mitochondria

Explanation: Although blood is an excellent source of DNA, the DNA does not come from the red blood cells, as these cells have no nuclei. Rather, the DNA comes chiefly from white blood cells in the blood

2104. Spirochete is an example of which type of bacteria?

• A. Aerobic
• B. Facultative
• C. Anaerobic
• D. Both Options A and B are correct

Explanation: Spirochaeta are free-living nonpathogenic inhabitants of mud and water, typically thriving in anaerobic (oxygen-deprived) environments

2105. In prokaryotes, the hair-like outgrowths which attach to the surface of other bacterial cells are _.

• A. Flagella
• B. Pili
• C. Capsules
• D. Plasmids

Explanation: Fimbriae and pili are hair-like appendages present on the bacterial cell wall similar to flagella. They are shorter than flagella and more in number. They are involved in the bacterial conjugation, attachment to the surface and motility.

2106. The nitrifying bacteria are an example of which of the following?

• A. Heterotrophic bacteria
• B. Saprotrophic bacteria
• C. Chemosynthetic bacteria
• D. Parasitic bacteria

Explanation: Chemosynthetic bacteria oxidise inorganic compounds like ammonia, nitrate, nitrite, sulphur or ferrous ions and use the energy thus released for their synthetic reactions. Nitrifying bacteria are chemosynthetic.

2107. What allows a bacteria to stain positively with gram stain?

• A. The bacteria is anaerobic
• B. The bacterial sample was pretreated with 3% ethanol
• C. The bacteria's periplasmic space
• D. The bacteria's thick peptidoglycan cell walls

Explanation: Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which allows them to take up the crystal violet colour of the Gram stain.

2108. A giant micro organism, which was discovered in the intestine of brown surgeonfish (Acanthurus nigrofuscus), is:

• A. A bacterium
• B. A virus
• C. A parasite
• D. Protozoa

Explanation: Epulopiscium fishelsoni is a very large bacterium that only lives in the gut of a brown surgeonfish found in the Red Sea.

2109. Which of the following is the most responsible factor for bacterial cell motility?

• A. Cillia
• B. Flagella
• C. Pili
• D. Pseudopodia

Explanation: The bacterial flagellum is a motile organelle composed of thousands of protein subunits. The filamentous part that extends from the cell membrane is called the axial structure and consists of three major parts, the filament, hook, and rod, and other minor components.

2110. A bacterium with a tuft of flagella at both poles is called:

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

Explanation: OPTION A: A lophotrichous bacterium has a group of two or more flagella inserted at one pole of the cell. OPTION B: In peritrichous bacterium, flagella are dispersed on the entire surface of the cell. OPTION C: A monotrichous bacterium possess a single flagellum. OPTION D: An amphitrichous bacterium is characterized by groups of flagella inserted at both ends of the cell. Hence, D is the correct option.