Free Biodiversity and Variety of Life MCQs with Answers

2231. Nitrifying bacteria belong to following group:

• A. Chemosynthetic
• B. Photosynthetic
• C. Parasitic
• D. Pathogenic

Explanation: The nitrifying bacteria of the soil are Nitrosomonas and Nitrobacter. They are called chemoautotrophs (chemosynthetic would be a general term) because they obtain energy from the oxidation of ammonium and nitrate ions.

2232. The chemical substances that are used to inhibit the growth of micro organism on living surfaces, are called:

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

Explanation: Antiseptics are used to inhibit the growth of bacteria.

2233. Which of the following provides resistance against high temperature?

• A. Cysts
• B. Spores
• C. Cell wall
• D. Capsules

Explanation: Endospores (spores withing the vegetative cells) are tough dormant structures that form inside the cell wall of certain types of bacteria, such as Bacillus. These tough capsules form in response to adverse conditions such as drought or high temperatures.

2234. Cell wall of gram-positive bacteria is composed of:

• A. Glycolipids
• B. Glycoproteins
• C. Lipoproteins
• D. Peptidoglycan

Explanation: Bacterial cell walls are made of peptidoglycan, also called as murein, which is made from polysaccharide chains cross-linked by unusual peptides containing D-amino acids.

2235. Many bacteria are motile due to presence of:

• A. Flagella
• B. Pilli
• C. Cilia
• D. Microtubules

Explanation: "The explanation for this question will be added soon!".

2236. Cell wall is only absent in:

• A. Archaeobacteria
• B. Eubacteria
• C. Mycoplasma
• D. Cyanobateria

Explanation: Mycoplasmas are a group of bacteria that are characterized by their lack of a cell wall, which makes them unique among bacteria. They belong to the class Mollicutes. Mycoplasmas are some of the smallest known free-living organisms and have a simple cell structure.

2237. Moist heat cause_and kill the microbes:

• A. Oxidation of proteins
• B. Coagulation of proteins
• C. Degeneration of nucleic acids
• D. Bursting up of cells

Explanation: Moist heat can cause the coagulation or denaturation of proteins. When proteins are exposed to high temperatures, their three-dimensional structure can be disrupted, leading to the loss of their functional shape. This process is often irreversible and causes the proteins to form clumps or solidify, which can be detrimental to the survival of microbes. The coagulation of proteins can result in the inactivation or destruction of essential microbial enzymes and structures, ultimately killing the microbes. In summary, moist heat primarily causes the coagulation of proteins, which leads to the inactivation of microbial enzymes and structures, ultimately killing the microbes. While the degeneration of nucleic acids and the bursting of cells can also occur, they are generally secondary effects in the context of microbial death caused by moist heat.

2238. Diameter of E. coli is_ to_ micrometer:

• A. 0.5-1.5
• B. 2.0-4.0
• C. 1.1-1.6
• D. 2.0-6.0

Explanation: The diameter of E. coli falls within the range of 1.1 to 1.5 micrometers. E. coli is a bacterium, and its typical size can vary depending on various factors such as growth conditions and strain. On average, E. coli cells are approximately 1-2 micrometers long and 0.5-1 micrometer in diameter. The given range of 1.1-1.5 micrometers falls within the expected diameter range of E. coli. In summary, option A) 1.1-1.5 micrometers is the most accurate choice for the diameter range of E. coli, based on its typical size.

2239. Killing bacteria from a living surface by using some chemical substance is called:

• A. Antisepsis
• B. Disinfection
• C. Disinfestation
• D. Chemotherapy

Explanation: Antisepsis refers to the process of killing or inhibiting the growth of microorganisms, particularly bacteria, on living surfaces such as the skin or mucous membranes. Antiseptics are chemical substances that are applied to living tissues to achieve this purpose. Examples of antiseptics include iodine, and alcohol. Antisepsis is commonly used in medical settings to prevent infections during surgical procedures or to clean wounds.

2240. Pick up the component which is comparatively in greater amount in Gram -ve cell wall:

• A. Lipids
• B. Peptidoglycan
• C. Teichoic acid
• D. Lipoteichoic acid

Explanation: "The explanation for this question will be added soon!".