Free Biodiversity and Variety of Life MCQs with Answers

2181. E. coli is a:

• A. Facultative
• B. Anaerobic
• C. Gram-negative
• D. All of these

Explanation: Escherichia coli (E. coli) is facultative anaerobe. it is anaerobic in the absence of oxygen, and it is also Gram-negative because its cell wall has a thin peptidoglycan layer and an outer membrane. Hence, all the given options are correct.

2182. Which true prokaryote is a photosynthetic bacterium?

• A. Cyanobacteria
• B. Nostoc
• C. Chlorella
• D. E. coli

Explanation: Cyanobacteria are known as blue-green algae and are true photosynthetic bacteria.

2183. Robert Koch discovered bacteria that cause?

• A. Tuberculosis and typhoid
• B. Tuberculosis and measles
• C. Tuberculosis and cholera
• D. All of the above

Explanation: German physician Robert Koch was one of the founders of bacteriology. He discovered the anthrax disease cycle (1876) and the bactana responsible for tuberculosis (1882) and cholera (1883).

2184. Streptobacillus is basically a:

• A. Single cell
• B. Chain of bacilli
• C. Pairs of bacilli
• D. All of the above

Explanation: Streptobacillus is a type of bacteria that appears in the form of a chain of rod-shaped cells (bacilli). The prefix "strepto-means chain, and "bacillus" refers to the rod shape. Therefore, Streptobacillus is not a singlo Tor pairs, but a chain of bacil

2185. A Dutch scientist Antone Van Leeuwenhoek used a simple microscope to describe bacteria and protozoa with accurate drawings and descriptions. He called these small creatures:

• A. Eubacteria
• B. Archaeobacteria
• C. Animalcules
• D. Prokaryote

Explanation: This option is correct because Animalcule (little animal', from Latin animal-the diminutive suffix-culum) is an old term for microscopic organisms that included bacteria, protozoans. and very small animals. The word was invented by 17th century Dutch scientist Antone Van Leeuwenhoek to refer to the microorganisms he observed in rainwater.

2186. Robert Koch postulated the ''Germ theory of disease''. Which one of these statements is not correct about this theory?

• A. A specific organism can always be found associated with a disease
• B. The organism cannot be isolated and grown in a pure culture in the laboratory
• C. The pure culture will produce the disease when inoculated into a susceptible animal
• D. It is possible to recover the organisms in pure culture from an experimentally infected animal

Explanation: This statement is not correct as organisms can be isolated and grown pure culture.

2187. The bacteria which range in size from 0.75-1.25 micrometers in diameter are:

• A. E. Coli
• B. Staphylococci and Streptococci
• C. Spirochetes
• D. Epulopiscium fishelsoni

Explanation: Staphylococci and Streptococci are 0.75-1.25 micrometer in diameter.

2188. While distinguishing between the contrasting features of gram-positive and gram-negative bacteria which of the following is a mismatched pair?

• A. Gram-positive bacteria-peptidoglycan
• B. Gram-positive bacteria-lipids
• C. Gram-negative bacteria-no outer membrane
• D. Gram-negative bacteria-less permeable

Explanation: Gram-negative bacteria have an outer membrane of lipoprotein which is absent in gram-positive bacteria.

2189. If we say that antibiotics kill the bacteria when it is rapidly dividing and growing phase, then an antibiotic penicillin will kill the bacteria during which phase?

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

Explanation: In this phase, bacteria are actively dividing and growing at their maximum rate. Antibiotics are most effective during this phase because they target rapidly dividing cells.

2190. Bacteria ranging in size from about 0.1 to 600μm:

• A. On the anterior side
• B. Over a single dimension
• C. In width
• D. In thickness

Explanation: Bacteria range in size from about 0.1 to 600µm over a single dimension, which is the ir length. This means they can vary in length from 0.1pm to 600µm.