Answer Key to Cell Division/Reproduction Study Guide 2015
Name__________________
1. Compare and contrast the process of asexual cell division for prokaryotic and eukaryotic cells,
to include the different names of each process. Sentences or a Venn diagram may be used.
Both make exact copies of the parent cell, to include the DNA. Binary Fission for prokaryotic cells is
a simple process where the DNA copies itself, the cell lengthens, and then splits in two. Mitosis for
eukaryotic cells is more complicated, to include chromosomes copying themselves exactly, and
then several steps with the final step resulting in two new identical cells with DNA and
chromosomes exactly equal to the original cell.
2. Compare and contrast asexual with sexual reproduction for eukaryotes, to include the names
of each process and the chromosomal outcome. Sentences or a Venn diagram may be used.
Both produce new cells. For Mitosis, the new cells will be exact copies of the parent cell. For
Meiosis, each new cell – called a gamete – has half the chromosomes of the parent cell, and there
are some slight changes in the DNA in the chromosomes due to genetic crossover.
3. The table below describes cell processes, but scrambled as to order or timing. Provide a name
for the processes shown (some may be “early and “late”) and list the timing from 1 to 7.
Timing Name of process
Description of process
(1-7)
Anaphase
The chromosomes separate and are pulled to opposite
5
sides of the cell by the spindle fibers.
4
Metaphase
The chromosomes line up at the equator of the cell.
Interphase
Normal operation of the cell, where DNA is not visible as
the chromosomes instruct the cell what operations to
conduct.
The chromosomes decondense, becoming invisible, and a
nuclear membrane forms surrounding the area where the
chromosomes had been.
DNA duplicates itself, chromosomes start to become
visible, and other cell organelles are copied.
1
Telophase
6
2
Early prophase
Late prophase
3
Cytokinesis
7
The nuclear membrane breaks apart. Chromosomes
shorten and are now completely visible. Two pairs of
centrioles move to opposite ends of the cell. Spindle
fibers attach from them to the chromosomes.
The cytoplasm splits in two as the cell membrane (or cell
wall also, for plant cells) pinches into two equal parts.
4. Explain at least three reasons why an organism might need to use mitosis to create new cells.
Cite specific examples of the organism and tissue involved.
Need for new cells via mitosis
Reason
Tissue
Organism
Organisms need to grow
Plant stem or tree trunk
Corn, oak tree, person, frog,
etc.
Many cells die a natural
death after a time period,
some end it by suicide – aka
apoptosis.
Skin cells
Human being
Cells can die from poisons,
bacteria, or injury, aka
necrosis
Poison from a spider or a
snake
Grazing horse, maybe a
person too.
5. “Too much of a good thing” was a phrase appearing over 500 years ago in a play by William
Shakespeare. Apply that phrase to mitosis, to explain both how mitosis can be considered a “good
thing” and how too much mitosis can be a very bad thing.
Mitosis is absolutely necessary for the three reasons shown in the answer to number 4. However, when
growing tissue reaches a point where it should stop growing, mitosis should slow down. When the cells
don’t slow down their growth, but keep on dividing, that is a form of cancer, and the result can be very
bad for the organism.
6. During late interphase, ALL cell organelles, including chromosomes, are duplicated. Yet, the steps of
mitosis focus MOST on what happens to the chromosomes. Explain why the chromosome duplication
is of greatest importance, and why errors in duplication of chromosomes can cause severe problems.
Because the chromosomes contain ALL the DNA that both acts as “control central” AND that passes
on genetic information to the offspring, AND because it contains the most complicated part of the
cell, it’s very important to get the copying done right. Making a mistake with copying one of the
several ribosomes, for example, just means that the other ribosomes have to a bit more work. But
making a mistake copying the information on one of the chromosomes can result in a mutation that
can lead to death. While some errors make no difference, and others get fixed, many errors in
copying the DNA in chromosomes can lead to death.
1.