ESSENTIAL CELL BIOLOGY, FOURTH EDITION
CHAPTER 18: THE CELL-DIVISION CYCLE
© 2014 GARLAND SCIENCE PUBLISHING
Overview of the Cell Cycle
18-1 For each of the following sentences, fill in the blanks with the best word or phrase
selected from the list below. Not all words or phrases will be used; each word or phrase
may be used more than once.
The four phases of the cell cycle, in order, are G1, __________________,
__________________, and __________________. A cell contains the most DNA after
__________________ phase of the cell cycle. A cell is smallest in size after
__________________ phase of the cell cycle. Growth occurs in __________________,
__________________, and __________________ phases of the cell cycle. A cell does
not enter mitosis until it has completed __________________ synthesis.
DNA  | M  | protein
G1  | nucleotide  | S
G2  | organelle
18-2 What would be the most obvious outcome of repeated cell cycles consisting of S phase
and M phase only?
(a) 
(b) 
(c)  | Cells would not be able to replicate their DNA.
The mitotic spindle could not assemble.
Cells would get larger and larger.(d) The cells produced would get smaller and smaller.
18-3 A mutant yeast strain stops proliferating when shifted from 25°C to 37°C. When these
cells are analyzed at the two different temperatures, using a machine that sorts cells
according to the amount of DNA they contain, the graphs in Figure Q18­3 are obtained.