Question

Difficulty: HardTransitions: Chronology and Sequence

The sentences below describe the historical development of penicillin as a therapeutic medicine. Arrange the sentences in the correct chronological and logical sequence.

  1. 1In 1928, Alexander Fleming discovered the antibacterial properties of a mold secretion he named penicillin, though his inability to isolate the unstable compound prevented immediate medical application.
  2. 2This decade-long research plateau was broken when Howard Florey and Ernst Chain assembled a team at Oxford to reinvestigate natural antibacterial agents, focusing their efforts on Fleming's discovery.
  3. 3After purifying and stabilizing the compound, the Oxford researchers demonstrated its therapeutic value in animal trials, confirming its potential to treat systemic infections.
  4. 4To scale up manufacturing for wartime casualties, the researchers collaborated with American factories, which successfully developed deep-tank fermentation methods for mass production.

Answer

The correct sequence begins with the discovery of penicillin in 1928, followed by the research plateau and the subsequent involvement of the Oxford team, then the purification of the compound for animal trials, and finally the transition to industrial mass production in collaboration with American factories.
The correct sequence begins with the discovery of penicillin in 1928. It then transitions to the decade-long research plateau that followed, which was ended by the Oxford team's work. Once the Oxford team focused on the compound, they purified and stabilized it for animal trials. Finally, the successful animal trials allowed researchers to collaborate with American factories to scale up mass production.

Step-by-Step Solution

1
Identify the initial event that establishes the topic and timeline.
The sentence introducing Alexander Fleming's 1928 discovery of penicillin establishes the baseline context.
Chronologically and logically, the initial discovery must precede any subsequent research efforts or production scales.
2
Look for transitions or cohesive devices linking to the initial discovery and its limitation.
The sentence describing the 'decade-long research plateau' connects directly to the inability to isolate the compound mentioned in the first sentence.
The phrase 'This decade-long research plateau' functions as an anaphoric reference to the stagnation following the 1928 discovery, marking the next chronological phase starting in the late 1930s.
3
Identify the logical next step of the Oxford team's research program.
The sentence starting with 'After purifying and stabilizing the compound' describes the immediate outcome of the Oxford team's focus.
Before conducting animal trials, the team first had to solve the instability issue mentioned in previous sentences, making this step logically prior to testing and manufacturing.
4
Determine the final phase of the process.
The sentence detailing the scale-up to mass production in collaboration with American factories concludes the sequence.
Mass production and industrial scaling naturally follow successful therapeutic validation in laboratory animal trials.

Key Concept

Chronological and logical flow in a process narrative.
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