If a person is infected with some deadly microbes to which quick immune response is required, we need to directly inject the preformed antibodies. This type of immunisation is known as:

Correct Answer: B

Rationale: Passive immunisation involves injecting preformed antibodies to provide immediate protection against microbes. This is suitable for quick immune response in infected individuals. Active immunisation, on the other hand, stimulates the body to produce its own antibodies over time, which is not ideal for immediate protection. Allergic immunisation is unrelated to providing antibodies. There is no immunisation type of "No such type of immunisation exist."

Correct Answer: D

Rationale: The correct answer is D, administration of immunoglobulin, for passive immunity. Immunoglobulin contains pre-formed antibodies that provide immediate protection against specific pathogens. Administering immunoglobulin transfers these antibodies to the recipient, offering temporary immunity. Choice A, having an acute disease, does not involve receiving external antibodies. Choice B, administration of a toxoid, induces active immunity against toxins, not passive immunity. Choice C, administration of a vaccine, stimulates active immunity by triggering the body to produce its antibodies, not providing immediate protection like passive immunity with immunoglobulin.

Correct Answer: C

Rationale: The correct answer is C: proteins. Gas vesicles are gas-filled structures found in certain bacteria and archaea to provide buoyancy. The membrane of gas vesicles is predominantly composed of proteins that form a semi-permeable barrier to trap gas. Proteins are essential for the structure and function of gas vesicles. Triglycerides (A) are not typically found in membrane structures, phospholipids (B) are more common in cell membranes, and lipopolysaccharides (D) are typically found in the outer membrane of Gram-negative bacteria, not in gas vesicle membranes.

Correct Answer: A

Rationale: Plaques are clear areas caused by virus infection in a lawn of cultured cells. This is because viruses infect cells, causing cell death and lysis, which results in clear areas. Choice B is incorrect because stained areas are not typically associated with plaques. Choices C and D are also incorrect as they refer to virus and bacterial colonies, respectively, not plaques.

Correct Answer: D

Rationale: The correct answer is D: H₂. In anaerobic respiration, H₂ can act as a terminal electron acceptor, so it is not an incorrect example. Nitrate, hydrogen sulfate, and iron hydroxide are all examples of terminal electron acceptors in anaerobic respiration. H₂ is commonly used in microbial processes as an electron donor, not as a terminal electron acceptor. This is because H₂ is typically oxidized to produce energy, rather than accepting electrons.