Transcript CH 12 CQ

Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 12
The Cell Cycle
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Questions prepared by
Louise Paquin
McDaniel College
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Prokaryotic Division
Why don’t prokaryotic cells need to go through
the same cell cycle as eukaryotic cells?
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S Phase
How might you prove experimentally that DNA
replication (and therefore the replication of
chromosomes) happens during the S phase of
the cell cycle and not during mitosis?
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Chromosomes in the Cell Cycle
At what part of the cell cycle would you see a
chromosome that looks like this?
Give your reasons.
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What do the differences
among the division of
these cells demonstrate?
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Which of the following best describes the kinetochore?
a) a structure composed of several proteins that associate with
the centromere region of a chromosome and that can bind to
spindle microtubules
b) the centromere region of a metaphase chromosome at which
the DNA can bind with spindle proteins
c) the array of vesicles that will form between two dividing nuclei
and give rise to the metaphase plate
d) the ring of actin microfilaments that will cause the appearance
of the cleavage furrow
e) the core of proteins that forms the cell plate in a dividing plant
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Rate of Mitosis
If you were to examine a sample of connective
tissue cells from a small but adult mammal and
a second sample from a fetus of the same
species, in which would you expect to find
more cells undergoing mitosis? Why?
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Regulation of the Cell Cycle
A. What would you expect to happen if you
fuse a cell in S with a cell in G1? Why?
B. What would you expect to happen to a
nucleus from a G1 cell if it is introduced into an
enucleated M cell? Why?
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Which of the following would need to be present to
produce a realistic signal to control the cell cycle?
(More than one may be required.)
a) a set of molecules that are sensitive to fluctuations
in the abundance of regulators
b) protein kinases
c) molecules that activate kinases
d) molecules that degrade activators
e) All of the above.
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Cancer Cells
At which part of the cell cycle would you expect
that a change in regulation could result in cancer?
Provide a reason for your answer.
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