Name: __________________________________ Period: ______
Explaining Eukaryotic Cell Cycle, Mitosis & Cytokinesis (animal cell)
Introduction
Cell division is more complex in eukaryotes than prokaryotes. Prior to dividing, all the DNA in a
eukaryotic cell’s multiple chromosomes are replicated. Its organelles are also duplicated. Then, when
the cell divides, it occurs in two major steps: mitosis & cytokinesis.
Cell division is just one of several stages that a cell goes through during its lifetime. The cell cycle is a
repeating series of events that include growth(G1), DNA replication(S), preparation for division (G2) and
cell division (M). The diagram in Figure 1 below represents the cell cycle of a eukaryotic cell. As you can
see, the eukaryotic cell cycle has several phases. The mitosis phase (M) actually includes both mitosis
and cytokinesis. This is when the nucleus and then the cytoplasm divide. The other three phases (G1, S,
and G2) are generally grouped together as interphase. During interphase, the cell grows, DNA replicates,
and the cell prepares to divide; on Figure 1 below label at which phase each of the events occurs during
interphase: G1, S, or G2 in the spaces provided.
G1:
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S:
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G2:
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In eukaryotic cells, the nucleus divides before the cell itself divides. The process in which the
nucleus divides is called mitosis. Before mitosis occurs, a cell’s DNA is replicated. This is necessary so
that each daughter cell will have a complete copy of the genetic material from the parent cell.
Chromosomes are coiled structures made of DNA and proteins. Chromosomes are the form of the
genetic material of a cell during cell division. During other phases of the cell cycle, DNA is not coiled into
chromosomes. Instead, it exists as a grainy material called chromatin.
DNA condenses and coils into the familiar X-shaped form of a chromosome, shown in the Figure 1
below, only after it has replicated. DNA has already replicated before mitosis begins, thus each
chromosome actually consists of two identical copies. The two copies are called sister chromatids or
singularly chromatids. They are attached to one another at a region called the centromere. Label the
each chromatid and the centromere in Figure 1 below in the spaces provided.
1. ________________________
2. ________________________
3. ________________________
Part One: Drawing and Explaining Eukaryotic Mitosis (animal cell)
Materials
 Colored pencils
 Textbook
 Worksheets or note sheets that you think might help.
Procedure
1. You will make drawings in the spaces provided of each phase indicated, be sure to include all
important structures. Your drawing should show three chromosomes, each in a different color.
2. In your own words on the lines below the spaces provided explain what events occur in each
phase.
3. This should be completed and handed-in by the end of class to receive full credit.
Drawings and Explanations
1. Interphase
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2. Prophase
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3. Metaphase
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4. Anaphase
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5. Telophase
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6. Cytokinesis
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