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
18.
Information in the passage most ████████ ████████ █████ ███ ██ ███ ██████████
a
Nerve cells in ██████ ██ █████ ████ ███ ██████ ██ ███ ████████ ██ █████ ████ ███████ ██████████ ███████ ████████ ██████████ ██ ████████ ███ ███████ ██ ████
Not supported, because we’re never told how or when antibodies are produced.
b
Nerve cells that ████ ██ ███ ███████ ██ ███ ███ ████ ████████ █████ ███ █████████████ █████████ ███ █████ ████ ████ ██ ███ ████████ ██ ████
Not supported, because the author doesn’t compare the nerve cells that grow without NGF to those that grow with NGF.
c
Few of the █████ █████ ████ ███████ ████ ██████ █████ ██████ █████ ███ ███████ ████ ███ ██████ ██ ███ ████████ ██ █████ ████ ████████
Not supported, because we have no evidence of the proportion of nerve cells that are needed by a developing organism other than that an organism does not need every single nerve cell that is formed. But it might still need the vast majority of nerve cells.
d
Some of the █████ █████ ████ ████ ██ ███ ████████ ██ ███ ███ ██████████ █████████ ██ █████ █████ ██ ██████ ██████ ██ ████████████ ████████
Not supported, because we have no evidence that some cells change into other kinds of living tissue. They might connect to tissue or die off, but we don’t know that they transform or convert into other things.
e
Some of the █████ █████ ████ ████ ██ ██ ██████ ██ ███ ███████ ████ ███ ██████████ ██████ ██████