Reading comp PrepTest 117 · Section 1 · Question 20

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).

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

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.

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.