Chapter 11: Cell Cycles - Endnotes
The phases of Prophase I are named for the appearance of a
thread-like structure, known as -nema. Leptonema means
"thin thread" and leptotene is the adjective applied to the term
stage, i.e. proper terminology is the leptotene stage of Prohase
I. The word stage is often omitted.
There is a shift in the terminology applied to these units. While
the two chromatids remain attached at the centromere, they are
known as chromatids. Immediately upon separating, each chromatid
becomes known as a chromosome and is no longer referred to as a
chromatid. This is the reason that a cell can divide one chromosome
(with two chromatids) into two cells, each with a chromosome - the
term applied to the chromatid is changed.
From J.H. Priest. Medical Cytogenetics and Cell Culture,
2nd ed. Lea & Febiger, Philadelphia, 1977.
Cells from Exercise 11.4 may be used, or cultures of tetrahymena,
yeast, or algae may be used.
This is calculated by plotting the growth of the culture and
determining the average time for the cell population to double.
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Cell Biology Laboratory Manual
Dr. William H. Heidcamp, Biology Department, Gustavus Adolphus College,
St. Peter, MN 56082 -- email@example.com