Self-study
This passage was adapted from an article published in 2000.
P1
Problem ·
Computer chips will hit a point where they can't be made any smaller
With current methods, transistors (devices that make up computer chips) cannot be made smaller than 25 nanometers.
Potential solution ·
Natural chemical processes might produce smaller molecules that act like transistors
Belcher and Hu ·
B and H are investigating peptides
Others are researching DNA to try to create small transistor-like molecules. B and H are researching something else -- peptides.
P2
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Background leading to research ·
Arose from research that found peptides could cause calcium carbonate to form structure found in abalone shell
B and H thought peptides might create crystalline structures associated with transistors.
B and H's research ·
Grew a billion different peptides, found that some can bind to semiconductor materials
P3
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Future research ·
Identifying additional organic compounds that can bind to additional semiconductor mateirals
Passage Style
Problem-analysis
Single position
19.
Which one of the following ██████████ █████████ ████████ ████ ██ ████ █████████ ██ ███ █████████ █████████ ████████ ████ ██ █████████ ██ ███ ████████
a
A group of ████████████ █████ ███████████████ ███ ███████ ██ ███ ████████ ██████████ ██ ███████ █████████ ████████ █████ ████████ ████ ████ ██ ███████ ██ █████████ █ █████ ██ █████ ███████ ███████ ███████ ██ █████ ███████ █████ ████ █████ ████ █████████ ██████████ ██ █████ ███████ █████████████
This describes abandoning one line of research to pursue another because of funding. That’s not what Belcher and Hu did. They started with one line of research (peptides and abalone shells) and applied what they learned to another, related line of research (peptides and semiconductors).
b
A group of ███████████ ████████ ███████ ████████ ████ ████ ███ ██████ ██ ███████ ███████ ██ █████ ████ █████ ███████ ████ ██ ███ ████ ██ █████████ ███████ ██ ███ ██████████ ██████████ ████ █████ ████ ██ ██████ ██ █████ ███████ █████████████ ████ ████████ ████ ███ ██ ███ ████ ██ █ ████████ ████████████
This describes testing a set of substances for one use and discovering they have another use. That’s not what happened with Belcher and Hu’s peptides. Belcher and Hu tested their peptides to see if those peptides could react with semiconductors, and discovered that yes, some can.
c
A group of ███████████ ███████████ ███████ ████████ ████ █████ ████ █████████ ███ █████ ██ ██ ██████ ██ █ █████████ ██ █████ ██████ ███████ ███████ ████████████████ ████ ████ ████ ████ ████ ███████████ ██ ████ ███ █████████ ██████████ ██ █████ ███████ █████████████
This describes creating a set of substances that, when combined, have two uses. That’s not what happened with Belcher and Hu’s peptides. Belcher and Hu created a set of substances (peptides), and found that a small fraction of those substances individually had a certain use (binding to semiconductors). They then created more new substances (new peptides related to, but not identical to, the previous ones) and found that some of those new substances individually had another use (gluing different crystals together). There’s nothing in there about combining peptides.
d
A group of ███████████ ████████ ████ █ ████████ ███ █████████ ██ ██ ██████████ ███████ ████ ██ █████ █████ ███ █████ █████████ ██ ███ ██████ ██ █ ███████ ████ ██████ █ ████████ ███████ ██ █████████ ███████ ███████ ████ ████ ███ ████ ██ █████ ███████ ████████████ █████ █████ ███████ ███████
This describes discovering that a certain substance used for a given purpose has an unintended side effect, and researching whether similar substances used for other purposes have similar side effects. That’s not what happened with Belcher and Hu’s peptides. Belcher and Hu discovered that a certain substance (a particular peptide) has a useful property (helping to build abalone shells), and researched whether similar substances could be created to have a similar useful property (helping to build transistors).
e
A group of ████████████ ██████ ████ █ ████████ ███ ████████ ██ █ ███████ ███████ ██ ████ ████████ ██ ████ █ ████ ██ ██████ ██████████ ███████████ ███████ ███████ ████ ███ █████ ████ ███ ████████ █████████████ ████████ ████ █████ ████ ████ ██████ ██ █████ ███████ █████████████
This describes making a discovery about a substance in nature, creating similar substances, and testing them for certain properties useful to human applications. This is analogous to Belcher and Hu’s work with peptides. They made a discovery about a substance in nature (peptides in the production of abalone shells), created similar substances (other peptides), and tested them for certain properties useful to human applications (building transistors).