The following is an excerpt from a recent scientific publication:“Non‑covalent interactions lie at the bases of the molecular recognition process. In medicinal chemistry, understanding how bioactive molecules interact with their target can help to explain structure‑activity relationships (SAR) and improve potency of lead compounds. In particular, computational analysis of protein‑ligand complexes can help to unravel key interactions and guide structure‑based drug design. The literature describing protein‑ligand complexes is typically focused on few types of non‑covalent interactions … hydrophobic contacts, hydrogen bonds, and salt bridges … stacking interactions involving aromatic rings are also relatively well known … potency optimization efforts are often focused on targeting these interactions.” Which types of noncovalent interactions are frequently exploited to optimize lead compound potency, according to this excerpt?

Which of the following nucleophiles is resonance stabilized?

Why is acetone less reactive toward nucleophilic attack than formaldehyde?

Which bond is formed when atoms share electrons equally?

The following is an excerpt from a recent scientific publication:“The pace and efficiency of drug target strategies have been emanating debates among researchers… Covalent inhibitors possess significant advantages over non‑covalent inhibitors, such that covalent warheads can target rare residues of a particular protein, thus leading to the development of highly selective inhibitors. However, toxicity can be a real challenge related to this class of therapeutics. From the challenges of irreversible drug toxicity to the declining reactivity of reversible drugs…” What selective advantage do covalent warheads confer in drug design, as described?

The following is an excerpt from a recent scientific publication:“Covalent inhibitors can achieve exquisite potency and durable target occupancy through a combination of covalent and noncovalent interactions. Drugs that possess a covalent mechanism‑of‑action encompass recent blockbusters (Clopidogrel) as well as early cornerstones of modern medicine (aspirin and penicillin). Despite this well‑documented history and the advantages from sustained target engagement, pharmaceutical companies have traditionally shied away from covalent drug programs due to concerns about potential idiosyncratic toxicity. However, clinical successes over the past decade (e.g. Ibrutinib), along with improvements in technologies used throughout the drug discovery pipeline, have reignited broad interest in this class of therapeutics.” What key advantage of covalent inhibitors is emphasized here in drug discovery?

Which base pairing feature underlies the genetic code’s redundancy during translation?

The following is an excerpt from a recent scientific publication:“Globular proteins have a core of hydrophobic amino acid residues and a surface region of water-exposed, charged, hydrophilic residues… Folding kinetics may trap a protein in a high-energy conformation … high-energy conformation may contribute to function… for example, the influenza hemagglutinin protein… two chains are held in a high‑energy conformation… when the local pH drops… conformation rearrangement enables it to penetrate the host cell membrane.” What structural feature contributes to hemagglutinin function?

Which base-pairing statement is correct for RNA and transcription?

The following is an excerpt from a recent scientific publication:“Amphetamine enters the presynaptic neuron … binds reversibly to TAAR1 or enters synaptic vesicles through VMAT2… When amphetamine reversibly binds to TAAR1, it reduces receptor firing rate … triggers signaling … result is transporter phosphorylation… transporters then operate in reverse…” What kind of interaction is primarily governing methamphetamine’s effects on transporter function?