Daily Olympiad: Biology - Biology Human Welfare [20260704]

Solution

Correct: A

Interferons do not directly degrade viral RNA. Instead, they induce the production of enzymes like protein kinase R (PKR) that inhibit viral replication by halting protein synthesis in infected cells.

Solution

Correct: A

Monoclonal antibodies are produced from a single B-cell clone, targeting a specific epitope. Polyclonal antibodies originate from multiple B-cell clones and bind multiple epitopes on the same antigen. This distinction is critical for precision in treatments like cancer therapy.

Solution

Correct: A

Plasmids are extrachromosomal DNA molecules used in genetic engineering to clone and express genes by inserting foreign DNA into bacterial cells. They are not involved in mitochondrial replication or protein synthesis directly.

Solution

Correct: A

The sgRNA hybridizes with the target DNA sequence and guides the Cas9 endonuclease to the specific genomic location. This allows precise DNA cleavage and editing. Other components like tracrRNA are part of the system but assist differently in the process.

Solution

Correct: A

Broad-spectrum antibiotics indiscriminately kill both pathogenic and beneficial bacteria, leading to dysbiosis and promoting resistance through selective pressure. This is a major clinical concern in antibiotic overuse.

Solution

Correct: A

Sulfonylureas bind to receptors on beta cells, causing ATP-sensitive K+ channels to close, leading to depolarization and insulin release. Other options describe mechanisms of other antidiabetic drugs (e.g., acarbose, SGLT2 inhibitors).

Solution

Correct: A

Live attenuated vaccines closely mimic natural infections, inducing robust T-cell and B-cell mediated immunity. However, they are contraindicated for immunocompromised individuals due to potential risk.

Solution

Correct: A

HbA1c reflects average blood glucose over 2-3 months, making it a standard diagnostic for assessing long-term glycemic control in diabetes. It does not correlate with acute glucose spikes.

Solution

Correct: A

Thalassemias involve reduced or absent α- or β-globin chain synthesis, whereas sickle cell is a structural mutation in β-globin. The distinction lies in quantitative vs. qualitative hemoglobin defects.

Solution

Correct: A

Cyclosporine inhibits calcineurin, preventing IL-2 transcription in T-cells and thereby suppressing T-cell activation. Other drugs act on different pathways, such as mTOR inhibition (sirolimus).