Free Biodiversity and Variety of Life MCQs with Answers

2351. Certain electromagnetic radiations below_ nm are effective in killing of microorganisms:

• A. 100
• B. 200
• C. 300
• D. 400

Explanation: This is a fact that you will need to remember that Certain electromagnetic radiations below 300 nm are effective in killing of microorganisms.The effective range for germicidal UV radiation is typically below 300 nanometers (nm). This range, specifically in the 100 to 280 nm region, is the most effective for disinfection and is often referred to as the germicidal or UVC range.

2352. Which of the following is not found in all bacteria?

• A. Cell membrane
• B. Nucleoid
• C. Ribosomes
• D. Capsule

Explanation: The capsule is a slimy, protective layer that surrounds some bacterial cells. It is composed of polysaccharides or similar materials and helps bacteria evade the host immune system and resist environmental stresses. However, not all bacteria possess capsules; it is a feature found in certain bacterial species but not in all. The capsule of a bacterium is a specific and well-defined structure. The capsule is a protective layer that surrounds the bacterial cell, located outside the cell wall (if present). It is composed of a gel-like substance, primarily consisting of polysaccharides or occasionally polypeptides.

2353. Students were asked to give a guess about a unicellular organism with darkly stained nucleus. Which of the following can be straight away excluded from the list:

• A. Paramecium
• B. Amoeba
• C. Plasmodium
• D. Lactobacillus

Explanation: Lactobacillus is a genus of bacteria, and bacteria do not have nuclei in the same way that eukaryotic cells (such as protists) do. Bacterial genetic material is contained within a region called the nucleoid, which is not membrane-bound and does not exhibit the same dark staining characteristics as eukaryotic nuclei. Since Lactobacillus is a bacterium and not a unicellular organism with a darkly stained nucleus, it can be excluded from the list.

2354. Arrangement of coccus bacteria in chain is called:

• A. Streptococci
• B. Staphylococci
• C. Tetrad
• D. Sarcina

Explanation: Streptococci is the correct answer. Streptococci refer to a chain-like arrangement of spherical bacteria (cocci). In this arrangement, the cocci divide in one plane, and the resulting daughter cells remain attached to form a chain. The term "strepto" in "streptococci" indicates this linear arrangement.

2355. The flagella of bacteria are composed of:

• A. Fibrin
• B. Tubulin
• C. Keratin
• D. Flagellin

Explanation: The flagella of bacteria are composed of flagellin, which is a protein. Flagellin is arranged in a helix, which forms the long, whip-like structure of the flagellum. The flagellum is attached to the cell membrane and the cell wall of the bacterium. Flagellin is a protein that makes up the structural components of flagella, the whip-like appendages that some microorganisms, including bacteria, use for motility (movement). Flagella allow these microorganisms to swim or move through their environment, and flagellin is an essential protein for their function.

2356. Which of the following are spiral-shaped bacteria?

• A. Cocci
• B. Bacilli
• C. Pseudomonas
• D. Spirillum

Explanation: A spirillum is a type of bacteria that has a spiral shape. They are typically rod-shaped, but they have a helix that can vary in length and tightness. Spirilla are often motile, meaning that they can move around. They have flagella, which are whip-like structures that help them to move.

2357. A bacterial cell, having plasma membrane with all things present within it is called:

• A. Cytoplasmic matrix
• B. Cytoplasm
• C. Protoplast
• D. Cell Structure

Explanation: A bacterial protoplast refers to a bacterial cell that has had its cell wall removed or partially digested, leaving only the cell membrane and cytoplasm. Protoplasts are typically derived from Gram-positive bacteria, as Gram-negative bacteria have an outer membrane that makes the removal of the cell wall more complex.

2358. All of the following are characteristics of prokaryotic cells except?

• A. Unicellular
• B. Lack of membrane-bound organelle
• C. Lack of a nucleus
• D. They are found in protists and fungi

Explanation: Prokaryotic cells are not typically found in protists or fungi. Instead, prokaryotic cells are a characteristic of bacteria and archaea. These two domains of life consist of organisms with prokaryotic cells. In prokaryotic cells, the genetic material is not enclosed within a true nucleus and is found in a nucleoid region within the cytoplasm. They lack membrane-bound organelles such as a nucleus, mitochondria, and endoplasmic reticulum, which are features of eukaryotic cells.

2359. Which of the following structures helps cyanobacteria to move?

• A. Flagella
• B. Capsule
• C. Gas vesicles
• D. None of these

Explanation: Cyanobacteria, also known as blue-green algae, can exhibit motility through a few different mechanisms, although many species are non-motile. Motility in cyanobacteria, when present, is generally slower and less efficient than that of flagellated bacteria. Some cyanobacteria exhibit gliding motility, while others may perform limited movement via the action of gas vesicles.

2360. In Prokaryotes,_are involved in respiration.

• A. Mesosomes and cell membrane
• B. Cell membraneand ribosome
• C. Mesosomes and ribosomes
• D. All of Above

Explanation: The cell membrane regulates the transport of proteins, nutrients, sugar, and electrons or other metabolites. The plasma membranes of bacteria also contain enzymes for respiratory metabolism. Respiratory enzymes are also present on the mesosomes.