Download Purpose: This exercise is designed to help you review the events

http://www.biology.arizona.edu/default.html
Purpose: This exercise is designed to help you review the events that occur in the cell cycle and the process of mitosis
that divides the duplicated genetic material creating two identical daughter cells.
Directions: Go to the website listed above and then follow the directions below and on the web page. When in doubt
READ!!!!!
1. Click on the Cell Biology link on the home page of the Biology Project.
2. Next, click on The Cell Cycle & Mitosis link.
3. Click on the vocabulary button at the bottom of the page.
4. Click on the Terms to know about Mitosis and Meiosis and define the following terms.
Chromatid:
Chromatin:
Chromosomes:
Histone:
Kinetochore:
Nucleosomes:
5. Return to the The Cell Cycle & Mitosis Tutorial by clicking the “back” button on the Browser twice.
Select the DNA Basics link. Answer the following questions.
6.
s What is the difference between chromatin during cell division and “interphase” (period between divisions) in terms of its
structure?
s Which structure appears under a microscope as “beads on a string?”
s Describe the structure of DNA (deoxyribonucleic acid).
s The process of _________________ is designed to insure that exact copies of the _____ _____ _____ in
_______________________ are passed on to ________________________ ____________________.
7. Hit the next button.
Answer the questions on the back of this page.
s Next to each of the cell cycle stages below, tell what the stage “stands for”in the first box and for the “S” and “M” stages,
describe what is taking place within the cell during these stages in the second box. Some info will need to come from your
packet.
G1SG2 M-
8. Click the next button.
9. Match the stage of Mitosis on the left with the correct description of the activities of that stage on the right.
______ Interphase
A) Spindle fibers align the chromosomes along the middle of the cell nucleus. This line is referred to as the
metaphase plate. This organization helps to ensure that in the next phase, when the chromosomes are separated,
each new nucleus will receive one copy of each chromosome.
______ Prophase
B) Chromatin in the nucleus begins to condense and becomes visible in the light microscope as chromosomes.
The nucleolus disappears. Centrioles begin moving to opposite ends of the cell and fibers extend from the
centromeres. Some fibers cross the cell to form the mitotic spindle.
______ Prometaphase
C) The nuclear membrane dissolves, marking the beginning of prometaphase. Proteins attach to the
centromeres creating the kinetochores. Microtubules attach at the kinetochores and the chromosomes begin
moving.
______ Metaphase
D) The cell is engaged in metabolic activity and performing its prepare for mitosis (the next four phases that
lead up to and include nuclear division). Chromosomes are not clearly discerned in the nucleus, although a dark
spot called the nucleolus may be visible. The cell may contain a pair of centrioles (or microtubule organizing
centers in plants) both of which are organizational sites for microtubules
______ Anaphase
E) Chromatids arrive at opposite poles of cell, and new membranes form around the daughter nuclei. The
chromosomes disperse and are no longer visible under the light microscope. The spindle fibers disperse, and
cytokinesis or the partitioning of the cell may also begin during this stage.
______ Telophase
F) The paired chromosomes separate at the kinetochores and move to opposite sides of the cell. Motion results
from a combination of kinetochore movement along the spindle microtubules and through the physical
interaction of polar microtubules.
______ Cytokinesis
G) In animal cells, cytokinesis results when a fiber ring composed of a protein called actin around the center of
the cell contracts pinching the cell into two daughter cells, each with one nucleus. In plant cells, the rigid wall
requires that a cell plate be synthesized between the two daughter cells.
Optional: View the Mitosis Animation by clicking on the link at the bottom left of this page.
10. Click the next button.
11. Now take The Cell Cycle & Mitosis Tutorial “Test Yourself.”
To begin the test click the following button:
s Keep track of how you do on the self test by writing down how many attempts it takes you to get the correct answer to each
question.
1
2
3
4
5
6
7
8
9
10
11
12. Next go to the next page by selecting this button:
13. Chose the Online Onion Root Tips link on this page.
14. Read the information very carefully. After each page, continue to the next page. Follow the directions on each page to
determine the percentage of time a cell spends in each phase of mitosis. Record your results in the table below as
instructed.
Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
Total # of
Cells
Percent of
Cells
Explain what conclusions you can make about how much time a cell spends in each of the stages based on the information above.