Free Biodiversity and Variety of Life MCQs with Answers

2291. Which one is a chemotherapeutic agent to destroy and stop the growth of bacteria?

• A. Phenol
• B. Spirit
• C. Pencilin
• D. Sulphuric Acid

Explanation: Correct, as it is an antibiotic that inhibits bacterial cell wall synthesis.

2292. In prokaryotic cells, which one of the following organelles is present?

• A. Mitochondria
• B. Nucleus
• C. Golgi apparatus
• D. Ribosomes

Explanation: Ribosomes - Correct. Prokaryotic cells have ribosomes (70S type) for protein synthesis, though they are smaller than eukaryotic ribosomes.

2293. Phycocyanin is a pigment present in cyanobacteria. Phycocyanin is of _ color.

• A. Green
• B. Blue
• C. Yellow
• D. Red

Explanation: Blue - Correct. Phycocyanin is a blue pigment found in cyanobacteria that assists in photosynthesis.

2294. In prokaryotes, the function of mitochondria is performed by which one of the following?

• A. Mesosome
• B. Periplasm
• C. Ribosome
• D. Plasmid

Explanation: Mesosome - Correct. In prokaryotic cells, mesosomes are infoldings of the plasma membrane that perform functions similar to mitochondria, such as cellular respiration.

2295. Sterilization of blood products is carried out by?

• A. Chemicals
• B. Drying
• C. Heat
• D. Radiation

Explanation: Radiation - Correct. Gamma or UV radiation is used to sterilize blood products without damaging them.

2296. Extremely thin appendages helping during conjugation in bacteria:

• A. Pili
• B. Membrane
• C. Flagella
• D. Tentacle
• E. Cilia

Explanation: The thin appendages that help bacteria in conjugation are pili. So option A is the correct answer.

2297. Syphilis is caused by a bacteria called as:

• A. Bacilli
• B. Trichomonas
• C. Neisseria gonorrhea
• D. Genital herpes
• E. Treponema palladium

Explanation: The correct answer is Option E. Syphilis is caused by a bacterium called Treponema pallidum. It is a spirochete bacterium that is transmitted through sexual contact or from mother to child during pregnancy. Treponema pallidum is the specific bacteria responsible for causing syphilis.

2298. Photosynthetic bacteria liberate:

• A. CO2
• B. H2S
• C. S
• D. H
• E. O

Explanation: In sulfur photosynthetic bacteria, the substance that donates hydrogen is hydrogen sulfide (H2S) and not water. Therefore there is no liberation of molecular oxygen, but there is a production of molecular sulfur (S2). (Oxygen and sulfur have same number of valence electrons.)

2299. Bacteria having flagella all over the surface:

• A. Lophotrichous
• B. Peritrichous
• C. Atrichous
• D. Monotrichous
• E. Diplotrichous

Explanation: Peritrichous bacteria are those that have flagella distributed all over their surface. The term "peritrichous" comes from the Greek words "peri", meaning "around", and "trichos", meaning "hair," indicating that the flagella are present around the entire surface of the bacterial cell. Source :

2300. _ are the structures formed by invagination of the plasma membrane and have been associated with cell division and DNA replication in prokaryotic cells.

• A. Lysosomes
• B. Mesosomes
• C. Golgi bodies
• D. Phragmoplasts

Explanation: Mesosomes are the structures formed by invagination of the plasma membrane and have been associated with cell division and DNA replication in prokaryotic cells.