Cell Cycle and Protein Synthesis

This assignment delves into the intricacies of the cell cycle, mitosis, and protein synthesis. It begins by outlining the stages of the cell cycle, emphasizing key events like DNA replication and chromosome segregation during mitosis. The assignment then explores the process of protein synthesis, detailing transcription, translation, and the roles of mRNA, tRNA, and ribosomes. It provides a comprehensive understanding of these fundamental biological processes.

Ch 3 Act 9 - Exploration of the cell cycle and cancer (22 pts)
Objectives:
 become familiar with the stages of the cell cycle and mitosis
 compare normal cell division with that seen in cancerous cells
Complete this assignment by following the directions on this handout rather than those on the
screen.
1. First click on “audio” and then click on the monitor in the illustration to view the video about the cell
cycle. As you do this, answer the following:
 In what form is the DNA of the cell during interphase? _It is in form of loosely packed
chromatin that is spread throughout the nucleus.________
 Besides the DNA, what else required for cell division is doubled during interphase?
_______The mitochondria double ___________
 What holds sister chromatids together? ___The Cohesin_______________
 During which phase are the sister chromatids split apart? _Anaphase_________________
(4 pts)
2. Click the “Information” button in the bottom right corner of the lab simulation. Read all of the
background information on cancer and the cell cycle. As you do:
List three examples of ways in which cells can become cancerous. (3 pts)
a. Through rapid multiplication of cells
b.Through genetic mutation
c. viruses can also cause cells to be cancerous. Most notably, especially cervical cancer results
from viruses in most cases. .
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List three unique characteristics of cancerous cells. (3 pts)
a.Immortality of the cancer cell such that they do not die.
b.Lack of contact inhibition..
c.Reversion of cells to an immature form such that they do not perform their intended
functions.
3. Next you will look at several slides of both normal and cancerous tissue and will compare their
rates of cell division.
a. Click on the microscope and you will see a slide of normal lung tissue.
b. Drag the appropriate cell cycle phase seen at the top to each of the empty boxes on the
slide. This will help you to learn to recognize each of the different phases.
c. When you are done, click on Check and labels for all cells will appear, or if one of your
labels is incorrect a red outline will appear around the box and you will be able to correct it.
d. Count up all of the cells in each phase and record the number in the table below. The total
number for each row should be 20.
e. Click on Tissue slides and select cancerous lung tissue – this should bring up a new slide
of cancerous lung tissue.
f. Repeat steps b thru d for this slide.
g. Click Tissue slides and select each of the other slides until you have data on all three
tissues (lung, stomach, ovary) both normal and cancerous.
4. Calculate the mitotic index for each type of tissue, both normal and cancerous.
mitotic index = (# cells dividing/total # cells) X 100 (6 pts)
TISSUE # cells -
Interphase
# cells -
Prophas
# cells - # cells - # cells -
Telophas
total #
cells in
Total
#
Mitoti
c
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e Metaphase Anaphase e mitosis
(all
stages)
cells index
Normal lung 19 0 0 1 0 20 20 5
Cancerous
lung
16 0 2 1 1 20 20 20
Normal
stomach
18 0 1 0 1 20 20 10
Cancerous
stomach
14 2 1 1 2 20 20 30
Normal ovary 19 0 0 1 0 20 20 10
Cancerous
ovary
12 2 1 2 3 20 20 40
5. Answer the following questions in complete sentences.
a. What does your data indicate about the rate of cell division in cancerous tissue compared
to the rate of cell division in normal tissue? (2 pts)The rate of cell division is higher in
cancerous tissue compared to the rate of cell division in normal tissue.
b. In this group of samples, which type of cancerous tissue has the fastest rate of growth?
(2 pts)
Cancerous ovary. It has the highest mitotic index indicating highest rate of cell division.
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c. Many chemotherapeutic drugs used to treat various cancers work by inhibiting DNA
synthesis. Explain how this action helps. (2 pts)
Cell division is accompanied by DNA synthesis/duplication to provide for the
daughter cell. The cancer treatment drugs inhibit DNA synthesis thus obstructing the cell
division process as there no duplicate DNA for the daughter cell.
Fill in the blank spaces. "Act 4" has the question order to be arranged and an answer sheet to transfer to.
Ch 3 Act. 8: Review of mitosis (13 pts)
The following are not in the correct order. Please answer the questions below.
1. Which cell is in metaphase? (1 pt)
C
2. Cells A and F show an early and late stage of the same phase of mitosis. What phase is it? (1 pt)
Prophase
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3. In cell A, what is the structure labeled X? (1 pt)
Centrosomes
4. Which cell is not in a phase of mitosis? (1 pt)
D
5. What two main changes are taking place in cell B? (2 pts)
-Nuclear membranes form around each of the two sets of chromosomes
-The spindle begins to breakdown as the chromosomes begin to spread out.
6. When during the cell cycle is the DNA of the cell doubled? (1 pt)
Interphase
7. When the DNA condenses during early prophase it goes from string like___strands_________
to rod like ______structures called chromosomes_______________________.(2 pts)
8. What is the advantage of having the DNA in this rod like form as it goes through mitosis?
(1 pt)
The chromatins are visible when the DNA is in this form
9. Why does cytokinesis not take place until late anaphase? (1 pt)
To allow for complete nuclei division thus ensuring each sister cell has a nucleus after separation.
10. If an animal cell with 72 chromosomes goes through mitosis, how many daughter cells will
be formed during one cell cycle? __2______
How many chromosomes will each cell have? ____72_____ (2 pts)
Act 4 Steps in protein synthesis
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A. RNA polymerase binds to DNA & separates the strands to expose the template strand
B. RNA polymerase constructs a strand of mRNA using the template strand of DNA
C. newly formed mRNA separates from DNA at termination signal
D. mRNA is moved along ribosome as tRNAs move into position
E. mRNA leaves the via a nuclear pore
F. large ribosomal subunit attaches to form functional ribosome
G. mRNA attaches to small ribosomal subunit and initiator Trna
H. peptide bonds form between adjacent amino acids on
I. mRNA is moved along ribosome as tRNAs move into position
J. stop codon is reached and a protein release factor binds
K. completed polypeptide is released from the ribosome
L. released polypeptide undergoes processing and folding
A
RNA polymerase binds to
DNA & separates the
strands to expose the
template strand
B
RNA polymerase constructs
a strand of mRNA using the
template strand of DNA
C. newly formed mRNA
separates from DNA at
termination signal
E
mRNA leaves the via a
nuclear pore
F.
mRNA is edited as introns
are cut out and exons are
spliced together
F
large ribosomal subunit
attaches to form functional
ribosome
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G
mRNA attaches to small
ribosomal subunit and
initiator tRNA
I
mRNA is moved along
ribosome as tRNAs move
into position
H
peptide bonds form between
adjacent amino acids on
tRNAs
J
stop codon is reached and a
protein release factor binds
K.
completed polypeptide is
released from the ribosome
I.
released polypeptide
undergoes processing and
folding
References
Blow, J.J. (2005). Preventing Re-replication of Chromosomonal DNA. Nat Rev Mol Cell Biol,6(6), 476-486
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Nature Education. (2014). Scitable. Retrieved from http://www.nature.com/scitable/topicpage/mitosis-
14046258
Pearson Education. (2014). Mitosis. BioCoach. Retrieved from
http://www.phschool.com/science/biology_place/biocoach/mitosisisg/anaphase.html
University of Liecester, (n.d). The Cell Cycle, Mitosis and Meiosis. Virtual Genetics Education Centre
Retrieved from http://www2.le.ac.uk/projects/vgec/highereducation/topics/cellcycle-mitosis-meiosis
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