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2.1 Cell Theory (p. 16) – August 27, 2012
1) State how many cells there were in the nervous system when the larva hatched from
the egg.
13 cells
2) State how many hours elapsed from hatching:
a. Until the first cell division occurs;
7 hours
b. Until the last cell division occurs.
33 hours
3) During the development of the nervous system, some cells undergo programmed cell
death (apoptosis). This is marked with an X. Deduce how many times apoptosis occurs
during the development of the nervous system.
Apoptosis occurs 9 times.
4) Deduce the maximum number of times cell division occurred, to produce an adult
nervous system cell.
Cell division occurs 4 times.
5) The diagram shows that there are 78 cells in the adult nervous system. Calculate the
percentage of the cells of an adult C. elegans that are part of the nervous system.
Approximately 8.1% of the cells in the adult C. elegans are part of the nervous system.