Free Biodiversity and Variety of Life MCQs with Answers

2321. Antibiotics can be used against:

• A. Herpes simplex
• B. Influenza
• C. Polio
• D. Salmonella typhi

Explanation: Caused by the bacterium Salmonella typhi, which is the agent of typhoid fever. Antibiotics are effective here and are used to treat the infection.

2322. The soluble shield of macromolecules which surrounds bacteria is called

• A. Pili
• B. Slime
• C. Capsule
• D. Flagella

Explanation: Slime is a loosely attached, easily removable layer that provides some protection but does not form a well-defined structure around the bacterium.

2323. The following form of circular double stranded, self-replicating DNA molecules present in many bacteria in addition to the chromosomes are not essential for bacterial growth and metabolism:

• A. Nucleoid
• B. Plasmids
• C. Mesosomes
• D. Nuclear region

Explanation: Plasmids are small, circular DNA molecules that exist independently of the chromosome and carry non-essential but often beneficial genes, such as antibiotic resistance.

2324. A tetrad is also known as

• A. Bivalent
• B. Duplicated chromosome
• C. Paired homologous chromosome
• D. Homologous and thickened chromosome

Explanation: A tetrad, formed during meiosis, consists of homologous chromosomes paired together.

2325. Which one is Monera?

• A. Nostoc
• B. Both 'E. coli' and 'Nostoc'
• C. None of the given options
• D. E. coli - Incorrect. While E. coli is Monera

Explanation: Monera includes all prokaryotic organisms, such as bacteria and cyanobacteria, making both Nostoc and E. coli members of this kingdom.

2326. Archaebacteria are mostly likely to occur in

• A. Soil
• B. Ice caps
• C. Freshwater
• D. Hydrothermal vents

Explanation: Archaebacteria, such as thermophiles, thrive in extreme environments like deep-sea hydrothermal vents.

2327. In prokaryotes, the genetic material is without:

• A. RNA
• B. DNA
• C. Membrane
• D. Cell membrane

Explanation: In prokaryotes, the genetic material is not enclosed by any membrane. Unlike eukaryotes, which have a true nucleus surrounded by a nuclear membrane, prokaryotes have a nucleoid region where the DNA lies freely suspended in the cytoplasm. There is no nuclear envelope, no membrane-bound nucleus, and no membrane around the DNA, which makes this the correct answer.

2328. Bacteria without any flagella is called:

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

Explanation: In atrichous bacteria, the cells do not possess flagella, so they are generally non-motile or have alternative means of movement. "Atrichous" is a term used to describe bacteria that lack flagella, which are the whip-like structures used for bacterial motility.

2329. These all are the function of flagella in a bacterium but which is the primary one:

• A. Flagellated bacteria can detect chemicals
• B. The flagellated bacteria moves in response to a chemical signal
• C. Help in motility
• D. On some bacteria flagella has a role in immunity

Explanation: The primary function of flagella is to provide motility for microorganisms, allowing them to move through liquid environments. Flagella are whip-like, hair-like, or tail-like appendages that extend from the surface of certain cells, including bacteria, archaea, and some eukaryotic cells.

2330. Pilli are hollow, non-helical, filamentous appendages in bacteria. Which one is not true for Pili:

• A. They are involved in mating process
• B. They are the means of attachments of bacteria to various surfaces
• C. They are made up of protein
• D. These are present in gram positive bacteria

Explanation: These are hollow, nonhelical, filamentous appendages. Pili are smaller than flagella and are not involved in motility. True pili are only present in gram-negative bacteria. They are made up of a special protein called pilin. They are primarily involved in a mating process between cells called the conjugation process. Some pili function as a means of attachment of bacteria to various surfaces.