PrepTest 117

[lcid:3564] Prep Test 117 LSAT — Reading Comp — S1 Reading comp

Passage

Questions 15-20  .        The survival of nerve cells, as well as their  . performance of some specialized functions, is Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Science and a discovery
  • Views, minor Meta-Structures, and the author's attitude
    • Science - “Neurotrophic” factors required by nerve cells (survival, function)
    • Discovery - Rita Levi-Montalcini (RLM) - 1950s - Discovered first (NGF) - Nobel Prize (1986)

Paragraph 2

  • Paragraph note
    • Process of discovery (series of experiments; starting in ‘40s)
  • Views, minor Meta-Structures, and the author's attitude
    • Study/Hypo 1 - Nerve cells in embryo programmed to die - RLM counted nerve cells to confirm
    • Study 2 - Mouse tumors grew nerve cells in chick embryos
    • Study 3 - New process (tissue culture) - Mouse tumors caused chick nerve cells to grow around them
    • Further research - Identified specific protein - “nerve growth factor” (NGF)

Paragraph 3

  • Paragraph note
    • Further research/science (how it works)
  • Views, minor Meta-Structures, and the author's attitude
    • NGF first of many cell-growth factors
    • Present in many tissues
    • Serves two purposes - Direct developing nerves to their targets; keep them alive (cells die if NGF goes away or anti-NGF)

Main Point: RLM’s discovery of nerve growth factor (NGF) and it’s role in developing nerve cells and keeping them alive was a “crucial development in the history of biochemistry” (Line 8).

Key Lines?

Lines 5-10 - An important discovery is noted

Lines 40-41 - Discovery is shown to be first of many in area

Lines 51-55 - Two key functions of discovery

Meta-Structure?

Important New Discovery - While many passages discuss a new theory that supplants an old one, this one focuses on a discovery that didn’t replace some old theory. Paragraph 1 features a discussion of the “crucial development in the history of biochemistry” by Rita Levi-Montalcini. This suggests the passage is going to explore this new discovery, and the Author’s opinion of it will serve as the main point. Since Paragraph 2 explains how the discovery was made and Paragraph 3 discusses some of the implications of it, we can confirm that that is the focus of the passage. Therefore, the Author’s opinion of the discovery and its importance is the main point of the passage, as we noted above (and it’s essentially just a restatement of Lines 5-10).

List (of Studies) - Studies are important on the LSAT, and so are lists. Paragraph 2 here serves as a list of studies that RLM performed in order to reach her important discovery. It’s a very extensive paragraph, so we should expect some questions on these studies.

Last Thoughts?

There’s a lot of science in this passage, which can make it easy to get lost in what’s going on. However, focus on important elements of logic, not of science. For instance, we don’t need to know all the details of the studies, just the broad strokes of them - we can always go back to find the answer to a question as long as we can identify which study it’s asking about. Same with the functions of NGF - we don’t need to understand what “neurotrophic” means, just that it involves directing nerve cells and allowing them to survive.

Question prompt

Information in the passage Remaining source text redacted.
Why the credited answer is right

Credited answer: E

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Science

Strategy Overview

Remind ourselves of the main point of the passage, then head to the answers, focusing on those that line up with the main point and then using our notes/the passage to find the correct answer

Answer Anticipation

This question stem provides no indication as to the topic of the correct answer or where it’ll show up in the passage. As such, we’ll need to rely on our big-picture understanding of the passage to answer this question. We should start by reminding ourselves of the main point (either by reviewing what we said after reading the passage or by rereading our answer to the main point question). From there, we can head to the answers, deferring on those that don’t line up with the main point. For those that do, we’ll use our notes and the passage to see if it’s correct.

Answer choices

  1. A
    Nerve cells in excess Remaining source text redacted.
    Why choice A is not credited

    (A) (Lines 55-59) Great, this question seems to be dealing with science… For these, we really need to rely on the passage and hope that our notes are strong enough to find relevant information quickly. For this one, it mentions anti-NGF antibodies. Those are mentioned at the very end of the passage. In that sentence, there’s no indication that the nerve cells themselves produce anti-NGF antibodies, so this answer is unsupported. Note that we focused on an easy-to-find element and then saw if a specific thing about it is stated in the passage. That’s how we’re going to handle the science here!

  2. B
    Nerve cells that grow Remaining source text redacted.
    Why choice B is not credited

    (B) The entire passage was about NGF and its effects on the development of nerve cells, so this answer about nerve cells that grow outside of NGF’s presence is out of scope of that main focus. We should defer/eliminate it.

  3. C
    Few of the nerve Remaining source text redacted.
    Why choice C is not credited

    (C) (Lines 11-14; Lines 55-59) The passage did talk about nerve cells dying, so those cells couldn’t be necessary to the organism. However, there’s no language suggesting that most cells die, so we can’t infer that few of them are necessary. Short version? There’s nothing strong enough in the passage to support the “Few” here, and we would have noted it if there were.

  4. D
    Some of the nerve Remaining source text redacted.
    Why choice D is not credited

    (D) (Lines 51-55) This answer is worthy of consideration because “Some” is very weak, but the passage doesn’t talk about nerve cells converting to other types of cells. In fact, the passage states that NGF directs nerve cells and is responsible for their survival - there’s no discussion of a role of any chemical in converting those cells to other types of cells.

  5. E
    Some of the nerve Remaining source text redacted.
    Why choice E matches the stem

    (E) (Lines 17-20) Much like (D), this answer is worthy of consideration because it’s weak (“Some”), and it also reflects our understanding of the passage in that some nerve cells end up dying. In discussing RLM’s research, her first experiment showed that “many more nerve cells” are produced than are “finally required.” As such, not all of them end up serving their purpose, which is to connect to certain target cells and transmit information. This answer is therefore supported by the passage, so it’s the correct answer.

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