Reading comp PrepTest 155 · Section 3 · Question 16

Passage Summary Topic:
Science

Paragraph 1

• Paragraph note
  • Problem (making computer chips smaller) and one possible solution (using peptides)
• Views, minor Meta-Structures, and the author's attitude
  • Definition of "transistor": electronic devices that make up computer chips (third sentence)
  • Definition of "peptide": amino acid that makes molecular patterns (last sentence)
  • Cause-and-effect relationships:
    • Competition to make computer chips smaller has caused technologies to advance and economies to grow (first sentence)
  • Comparisons:
    • With current methods, transistors cannot be smaller than 25 nanometers, but living cells can make complex structures smaller (fourth setnece)
    • Most research into making computer chips smaller involves using DNA to assemble smaller computer chips, but Hu/Belcher attempt to use peptides/amino acids (last sentence)
  • Author's attitude: "revolution" (first sentence); "may be hope" (fourth sentence)

Paragraph 2

• Paragraph note
  • Belcher and Hu's research (developed new peptides to bind to semiconductor materials)
• Views, minor Meta-Structures, and the author's attitude
  • Cause-and-effect relationship:
    • A specific peptide causes calcium carbonate to turn into the structure found on abalone shells (second sentence)
  • Comparisons:
    • If a peptide can grow calcium carbonate into an abalone shell, a similar peptide could direct the growth of semiconductor materials to transistors (third sentence)
    • To find more peptides that could attach to semiconductor materials, Belcher and Hu used a process similar to accelerated evolution (last sentence)
  • List of semiconductor materials:
    • silicon, gallium arsenide, indium phosphide crystals (fifth sentence)
  • Author's attitude: "not only ... but also" (sixth sentence); "initially promising" (last sentence)

Paragraph 3

• Paragraph note
  • Belcher and Hu's remaining goals (find more peptides that bind) and progress (promising)
• Views, minor Meta-Structures, and the author's attitude
  • Author's view:
    • Belcher and Hu are making promising advancements in finding order to use peptides to bind to semiconductor materials (second through last sentence)
  • Comparison:
    • New peptides that can bind two different crystals function similarly to a glue (fourth sentence)
  • Author's attitude: "making progress" (second sentence); "ballooned into the hundreds" (third sentence); "will take that kind of finesse" (last sentence)

Main Point:
Hu and Belcher's promising research into using peptides to bind to computer-chip materials might allow scientists to work around the current theoretical minimum size of computer chips.

Key Lines?
Paragraph 1, Sentence 2 (P1, S2) - Problem introduced
P2, S3 - Possible solution
P3, S2-4 - Author's evaluation of the solution

Meta-Structure?
Problem/Solution: This passage best fits the Problem/Solution Meta-Structure*. The author describes a problem contemporary — well, actually, 2000s-era — technologists face: how to make computer chips smaller than the laws of physics will allow. The rest of the passage focuses on one potential solution: Belcher and Hu's use of organic compounds known as peptides to bind together computer chip materials.

In a Problem/Solution passage, the author's opinion of the proposed solution is the passage's main point. The author provides their opinion in the last paragraph. The author notes that Belcher and Hu haven't cracked the code yet, but they're making promising advancements. So, we've summarized the main point as, "Hu and Belcher's promising research into using peptides to bind to computer-chip materials might allow scientists to work around the current theoretical minimum size of computer chips."

*Some may see this as an Innovative Subject passage, since Belcher and Hu utilize such a unique approach. If this understanding of the passage makes more sense to you, that's a-OK! The Meta-Structures are here to help us think about a passage's overarching structure and ideas. We don't have to agree on which Meta-Structure a passage has to realize the benefits of the Meta-Structures.

Last Thoughts?
It's important to note, from the last paragraph, that Hu and Belcher haven't solved the problem yet — they're still working on it! The first line of the last paragraph lets us know that they haven't yet been able to assemble a circuit using peptides.