Free Biodiversity and Variety of Life MCQs with Answers

3101. Endotoxins are released only when bacteria

• A. Excrete
• B. Reproduce
• C. Decline phase
• D. Stop phase

Explanation: At the decline phase, bacterial growth decreases exponentially and many bacteria begin dying due to lack of nutrients or unfavorable changes in body conditions. Endotoxins are components of bacterial gram-negative membranes that are released to the external environment when a bacterial cell dies. Bacteria don't excrete endotoxins as waste material.

3102. Archaea live in both extreme and moderate environments those living in extreme condition are called:

• A. Extremophile
• B. Methanogen
• C. Extremophyte
• D. Extremogeus

Explanation: The correct term for organisms that live in extreme environments is extremophile. These organisms have adapted to survive in harsh conditions such as extreme heat, cold, acidity, or salinity, which would be detrimental to most other life forms.The other options are incorrect for the following reasons:Methanogen: While methanogens are a type of extremophile, the term specifically refers to those archaea that produce methane, and not all extremophiles are methanogens.Extremophyte: This term inaccurately combines concepts and is not used in scientific contexts to describe extremophiles.Extremogeus: This is not a recognized term and appears to be a misspelling or misunderstanding of 'extremophile'.

3103. The Sulphur Bacteria which obtain energy by oxidizing H2S instead of water is called:

• A. Alpha proteobacteria
• B. Beta proteobacteria
• C. Gamma proteobacteria
• D. Delta proteobacteria

Explanation: The correct answer is Gamma proteobacteria. This group includes chemolithotrophic sulfur bacteria, which are capable of oxidizing H2S to obtain energy. This oxidation process releases energy that the bacteria utilize for growth and reproduction. These bacteria play a crucial role in the environment by participating in the sulfur cycle and have potential applications in biotechnology.In contrast, Alpha proteobacteria and Beta proteobacteria typically use organic compounds for energy, and Delta proteobacteria are more commonly associated with sulfur compound reduction rather than oxidation.

3104. The first that oxygenated the atmosphere were:

• A. Cyanobacteria
• B. Phototrophic organisms
• C. Anaerobic organisms
• D. All of the above

Explanation: It is a fact that the first organisms that oxygenated the atmosphere were cyanobacteria

3105. Rhizobium belongs to:

• A. Beta-protobacteria
• B. Gama-protobacteria
• C. Alpha-protobacteria
• D. Delta-protobacteria

Explanation: Rhizobium belongs to alpha proto-bacteria, this is a fact and has to be learnt

3106. Myxospores are the spores produced by:

• A. Fungi
• B. Bacteria
• C. Algae
• D. Plants

Explanation: Myxospores are actually not spores produced by fungi, but rather by certain groups of bacteria called Myxobacteria. These bacteria are known for their unique life cycle, which involves the formation of myxospores under certain conditions. These myxospores are specialized structures that allow the bacteria to survive unfavorable conditions and then germinate when conditions become more favorable. So, in short, myxospores are produced by Myxobacteria, not fungi.

3107. The example of atrichious bacteria is:

• A. Bacill
• B. Spirilla
• C. Vibrio
• D. Cocci

Explanation: Bacillus is an example of bacteria that can be atrichous, meaning they do not have flagella or hair-like structures for movement. These bacteria are typically rod-shaped and can be found in various environments.

3108. The Peptidoglycan layer is found in the cell Of:

• A. Bacteria
• B. Algae
• C. Fungi
• D. Both (A) & (B)

Explanation: The peptidoglycan layer is found in the cell wall of bacteria. It is a unique structural component that provides strength and rigidity to the bacterial cell. This layer is composed of a mesh-like network of sugar chains cross-linked by short peptide chains. The peptidoglycan layer helps protect the bacterial cell from external stresses and maintains its shape.

3109. A bacterium with single polar flagellum is:

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

Explanation: A bacterium with a single polar flagellum is classified as Monotrichous. This means that the flagellum is located at one end (pole) of the bacterial cell.

3110. Red tides in oceans are produced by:

• A. Diatoms
• B. Dinoflagellates
• C. Water molds
• D. Myxomycota

Explanation: The rapid increase in the population of red dinoflagellate (a type of algae), causes the sea to appear red, which is responsible for the occurrence of red tides.