Free Biodiversity and Variety of Life MCQs with Answers

2131. Which of the following is used for sterilization?

• A. All of these
• B. Moist heat
• C. Gamma rays
• D. Dry heat

Explanation: Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents like prions present on/ in a specific surface, object, or fluid, for example, food or biological culture media. All of the given ways can be used for sterilization.

2132. Which of the following is a spiral-shaped bacteria?

• A. Cocci
• B. Bacilli
• C. Streptococcus
• D. Spirochete

Explanation: Mainly, bacteria have three shapes: spherical, rod-shaped, and spiral. 1. Spherical: A coccus is a spherical bacteria. Examples of cocci are Streptococcus pneumonia, Neisseria meningitides. 2. Rod-shaped: Bacilli are straight or rod-shaped organisms. When curved into a form resembling a comma, they are known as vibrio, and when present as a stack of coins, they are known as a palisade. Examples of rod-shaped bacteria are Escherichia coli, Pseudomonas. 3. Spiral: Spirochetes are spiral bacteria that usually occur singly or in colonies. An example is Treponema pallidum.

2133. Which of the following bacteria is equal to the size of the hyphen?

• A. Mycoplasma genitalum
• B. Staphylococcus aureus
• C. Streptococcus pneumoniae
• D. Eulopiscium fishelsoni

Explanation: Epulopiscium is a group of Gram-positive bacteria that have a symbiotic relationship with surgeonfish. These bacteria are known for their unusually large size, many ranging from 200-700 μm in length. the smallest genus is mycoplasma bacteria.

2134. Which part of bacteria is resistant to antibiotics?

• A. Capsule
• B. Slime
• C. Spore
• D. Cell wall

Explanation: In the bacterial cell wall, lying between the outer membrane layer and the cytoplasmic membrane is a site where some species of enzymes called beta-lactamases are present that degrade penicillins and other beta-lactam drugs. The capsule is a gelatinous layer covering the entire bacterium. It plays a role in the adherence of bacteria to human issues. A slime layer is an additional layer that can be produced in ground-dwelling prokaryotes to prevent unnecessary drying due to annual temperature and humidity shifts. Spore formation is a type of asexual reproduction in bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other.

2135. Bacteria and fungi are examples of

• A. Producers
• B. Decomposers
• C. Consumers
• D. Denvers

Explanation: Bacteria and fungi are examples of decomposers, and gain energy from breaking down dead organisms or waste from other organisms.

2136. Most widespread problem of the antibiotics misuse is the

• A. Rapid cure
• B. Increased resistance in pathogen
• C. Disturbance of metabolism
• D. Immunity

Explanation: Misuse and overuse of antibiotics gives the bacteria more chances to develop resistance to that antibiotic, and this resistance can be shared between different species.

2137. Bacterial 'death rate' is equal to 'birth rate; in:

• A. Lag phase
• B. Log phase
• C. Death phase
• D. Stationary phase

Explanation: Option A is incorrect because Lag phase is phase of no growth and bacteria prepare themselves for division.Option B is incorrect because Log phase is the phase of rapid growth, bacteria divide at exponential rate.Option C is incorrect because Death phase is phase in which bacteria start dying, and death rate is more than reproduction rate.Option D is correct since At stationary phase bacterial death rate is equal to reproduction rate.

2138. Antibiotics are produced by fungi and certain bacteria of group:

• A. Actinomycetes
• B. Oomycetes
• C. Ascomycetes
• D. Basidiomycetes

Explanation: Antibiotics are synthesized and secreted by certain bacteria (actinomycetes) and fungi. (PTB)

2139. Which of the following bacteria have more lipids in their cell wall?

• A. Gram-positive bacteria have more lipids in their cell wall
• B. Gram-negative bacteria have more lipids in their cell wall
• C. Lipids are absent in cell wall of both gram positive and negative bacteria
• D. Both have equal amount of lipids

Explanation: Gram-negative bacteria have a more complex cell wall structure compared to gram-positive bacteria. The outer membrane of gram-negative bacteria contains lipopolysaccharides (LPS), which are lipid-rich molecules. This presence of LPS contributes to a higher lipid content in the cell wall of gram-negative bacteria. In contrast, gram-positive bacteria have a simpler cell wall structure with a thicker layer of peptidoglycan and fewer lipids.

2140. When cocci form long chain of cells, the arrangement is termed as:

• A. Staphylococcus
• B. Sarcinae
• C. Streptococci
• D. Cocci

Explanation: Pair of cocci are, called diplococci Rows or chains of cells are called streptococci. Grapelike clusters of cells are staphylococci. Packets of eight or more cells are, sarcinae. Group of four cells in a square arrangement is tetrad.