Free Kingdom Prokaryotae MCQs with Answers

161. Maintaining the microbial population at a constant level is called:

• A. Microbistatic approach
• B. Microbicidal approach
• C. Bactericidal approach
• D. Antenatal approach

Explanation: Reproductive capacities of the cells are inhibited and the population of microbes is maintained at constant size by microbistatic.

162. Germ theory was presented by:

• A. Robert Koch
• B. Antonie van Leeuwenhoek
• C. Robert Hooke
• D. Robert Brown

Explanation: Proposing the germ theory of disease was the crowning achievement of the French scientist Robert Koch. Robert Hooke discovered the Law of Elasticity (or Hooke's Law) and did a huge amount of work on cell theory. Robert Brown used a microscope to describe the nucleus of a cell. He also developed the idea of what is now called the Brownian motion which explained the random movement of minute particles in a fluid.

163. Rod-shaped bacteria are known as:

• A. Cocci
• B. Bacilli
• C. Spirilla
• D. None of these

Explanation: Bacteria are classified according to their shape, or morphology. Spherical bacteria are known as cocci, rod-shaped bacteria are bacilli, and spiral-shaped bacteria are spirilla.

164. Which of the following is true of both bacterial conjugation and meiosis?

• A. Both processes produce four haploid cells
• B. Both processes are a form of asexual reproduction.
• C. Both processes involve genetic recombination
• D. None of these

Explanation: This means that they both involve the mixing of genetic material from two different cells. In bacterial conjugation, the plasmid that is transferred can contain new genes that can be incorporated into the recipient cell's genome. In meiosis, the chromosomes are recombined, which means that they are exchanged between the two homologous chromosomes. This process results in the production of new combinations of genes, which is essential for genetic diversity.

165. A Dutch scientist firstly observed very small creatures in:

• A. Vinegar
• B. Saliva
• C. Rain water
• D. All of Above

Explanation: Correct option is C. Anton Van Leeuwenhoek is known as the father of microbiology due to his findings with his novel microscopes. No one of his time had microscopes that were able to see things as small as he saw. He was the first to see single-cell organisms. A V Leeuwenhoek discovered bacteria in rainwater.

166. Cell wall is only absent in the following group of bacteria

• A. Staphylococci
• B. Pseudomunas
• C. Diplococcus pneumonia
• D. Mycoplasmas

Explanation: Correct option is D. Examples of bacteria that lack a cell wall are Mycoplasma and L-form bacteria. Mycoplasma is an important cause of disease in animals and is not affected by antibiotic treatments that target cell wall synthesis.

167. What is the strengthening material of the prokaryotic cell wall?

• A. Cellulose
• B. Chitin
• C. Silica waxes and lignin
• D. Peptidoglycan or murein

Explanation: Prokaryotic cell wall; It lacks cellulose. Its strengthening material is peptidoglycan or murein.

168. Which of these processes is the means by which a bacterium can directly uptake and incorporate foreign DNA from the environment into its genome?

• A. Transduction
• B. Transformation
• C. Binary Fission
• D. Conjugation

Explanation: Option B is correct since the transformation is the process of transmitting genetic information from one bacterium to another bacterium causing it to transform (change). Option A is incorrect since transduction is the process in which genetic material is transferred from one bacterium to another by a third party which is a bacteriophage. Option C is incorrect since binary fission is the asexual mode of reproduction of bacteria. Option D is incorrect since conjugation is the process of transfer of genetic material from one bacterium to another through a tube called the conjugation tube or cytoplasmic bridge

169. How much smaller are viruses than bacteria?

• A. 20 to 2000 times
• B. 10 to 1000 times
• C. 500 times
• D. 3000 times

Explanation: Viruses are 10 to 1000 times smaller than the smallest bacteria. The smallest bacteria, mycoplasma has a size of approximately 0.2 - 0.3 μm.

170. Which of the following will not survive in the presence of oxygen?

• A. Both B and D
• B. Facultative anaerobe
• C. Constitutive aerobe
• D. Obligate anaerobe

Explanation: Obligate Anaerobe organisms cannot survive in the presence of oxygen. It lacks the necessary enzymes and metabolic pathways to utilize oxygen and may even be harmed by it. Obligate anaerobes require an oxygen-free environment to survive.