Self-study
P1
The survival of nerve cells, as well as their performance of some specialized functions, is regulated by chemicals known as neurotrophic factors, which are produced in the bodies of animals, including humans. ███
Context ·
Nerve cells are regulated by chemicals called neurotrophic factors
Spotlight ·
Levi-Montalcini's discovery of NGF was important development in biochemistry
NGF was the first known neurotrophic factor.
P2
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Levi-Montalcini's hypothesis ·
Many nerve cells are programmed to die
Experimentation ·
Discovered that nerve development could be stimulated in chick embryos by implanting tumors
Additional hypothesis ·
Chemical produced by tumors caused nerve growth
Experimentation ·
Tissue culture method confirmed hypothesis and identified the "nerve growth factor" (NGF)
P3
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Later research ·
NGF directs nerves toward appropriate connections, and is necessary for survival of nerve cells
Passage Style
Single position
Spotlight
20.
Which one of the following ██ ████ ████████ █████████ ██ ███ ███████████ ██ ███ ████████
a
Some of the ███████ ████ ███ ██████ █████████ ██ █████████ ██ █████████████████ ███████ ██ █████ ██████ ███████ ████ ███ ██ ████████████ ███████ █████ ████ ████
Not supported, because we have no evidence that other neurotrophic factors were involved in the chick embryo experiments conducted by Levi-Montalcini. We know other factors have been identified in subsequent research, but we don’t know whether those factors are relevant to chick embryos.
b
Although NGF was ███ █████ ████████████ ██████ ██ ██ ███████████ ████ █████ ████ ███████ ███ ███ ████ ██████████ ███████████
Not supported, because the author never compares the level of undrestanding of NGF compared to other factors. We have no reason to believe NGF isn’t equally understood or even more understood than other factors.
c
In her research ██ ███ █████ ███ ██████ ███████████████ ██████████ █████ ████████████ ███████ ██ ████████ ██ ████
Not supported, because we don’t know whether Levi-Montalcini herself identified other factors besides NGF. We know that other factors have been identified, but we don’t know whether they were identified by Levi-Montalcini.
d
Some neurotrophic factors █████ ████ ███ ███████ █████████ ████ ███ ███ ████████████ ██████████ ██ ███ ████████
e
The effects of ███ ████ ███████████████ █████ ██ ███ █████ ██████ ██████████ ███ ████ ██████ ██ █████ ████████████ ███████ ███ █████████ ██ ███ ████████
Not supported, because we have no evidence that other neurotrophic factors were involved in the chick embryo experiments conducted by Levi-Montalcini. We know other factors have been identified in subsequent research, but we don’t know whether those factors are relevant to chick embryos.