Patients with recurrent infections of Neisseria meningitidis, an extracellular bacterial pathogen that causes meningitis, were found to have defects in complement activation on the bacterial surface, a process that for this bacterium is dominated by alternative complement activation leading to C3b deposition on the pathogen surface. Based on these data, the identity of the green neutrophil mediator in Figure Q2.19 is likely to be:

Correct Answer: D

Rationale: C3b is deposited on Neisseria via alternative pathway, aiding neutrophil phagocytosis; Factor B and properdin assist, but C3b is key.

Correct Answer: D

Rationale: Plant hormones like ethylene, gibberellins, and auxins are used to control fruit processes, produce seedless fruits, and act as herbicides. All options are correct.

Correct Answer: D

Rationale: Antibodies are proteins made of polypeptide chains, specific to adaptive immunity, not amino acids, lipids, or carbohydrates.

Correct Answer: D

Rationale: Cytotoxic T cells destroy infected cells via perforin and granzymes, unlike macrophages (phagocytosis), plasma cells (antibodies), or B cells (humoral).

Correct Answer: B

Rationale: Eosinophils target antibody-coated parasites (e.g., helminths) via degranulation, unlike macrophages, neutrophils, or basophils.