Biology 160
NAME: _______________________________________
Reading Guide 09: Somatic Cellular Reproduction
This is DUE: __________________
Come prepared to share your findings with your group.
*As before, please turn in only the Critical Thinking questions on a separate sheet of paper.
** Fill this reading guide out as you are reading the chapters. This will help you to pull out the important
information that will help us to understand how cells respond to the environment and reproduce.
Readings:  Essential Biology, 4th or 5th Ed. (Simon, Reece, & Dickey)
Ch 8, pg. 120-129 (What Cellular Reproduction Accomplishes, The Cell Cycle and Mitosis)
Ch 11, pg 227 (PCR)
While reading these chapters, constantly ask yourself, “How is this information helping me to understand how
my cells respond to the environment and reproduce?”
**Before reading this chapter watch the following video on YouTube:
http://www.youtube.com/watch?v=Hm03rCUODqg&NR=1&feature=fvwp
This is a video of breast cancer cells dividing in a cell culture dish. The video has been speeded up to show 3
days worth of time in just under 30 seconds. The dark circle in the middle of each cell is the nucleus.
1) Watch it once just to marvel at it.
2) Watch it a second time, but first, pick one cell to follow during the entire time.
3) Write down your observations here. Think about cell size and shape, movement, time, and cell structures as
you observe:
Chapter 8, pg 120-129 (What Cellular Reproduction Accomplishes, The Cell Cycle and Mitosis)
1. To all the words/phrases in the text that are in BOLD: Highlight in your text or rewrite them or organize
them in some way (like flash cards or a table) to help you to learn and understand them.
2. Name a few of the important roles that cell division plays in your life according to your text.
3. Critical Thinking: Do you think you might need cell division in the following processes? Why or why not?
a) to repair a cut on your skin?
b) to grow your hair?
c) to remember the meaning of “cell division”?
d) to replace all those cheek cells that you scraped off?
e) to fight off a virus?
f) to move your finger?
g) to maintain your digestive tract?
4. What is a “chromosome”?
5. Note the use of the words “parental” and “daughter” cells. We’ll come back to them. According to the text,
“As a rule, the daughter cells, receive…?” (pg 122)
6. What is “the type of cell division responsible for asexual reproduction and for the growth and maintenance
of multicellular organisms” called? Write some of the examples from the text.
7. Think back: What is a “eukaryotic” cell?
8. About how many genes does a human cell have? Where are they located?
9. So, does a eukaryotic chromosome contain a short or long piece of DNA? About how many genes are on an
average chromosome?
10. How many chromosomes do the following organisms have in a typical cell?
a) human
b) mouse
c) dog
e) chimpanzee (look this up outside of text)
11. Chromosomes are made of chromatin (know this word!). What is chromatin?
12. What are the roles of the proteins in chromatin?
1. Role:
2. Role:
13. Think Back: What do you think is meant by “the activity of its genes”? Think back to Figure 11.8. A gene
can be turned on in response to a signal. In other words, the gene can be “expressed” in response to a signal
(gene expression). In similar words, the gene can be “activated” in response to a signal (gene activity).
14. How long would the chromosomes of a human cell stretch? (For comparison, your instructor is ~1.6 meters
tall)
15. How can all of this DNA be packed into the tiny nucleus of each cell (remember how big the nucleus was in
your cheek cell)? Redraw Figure 8.4 making sure to understand the terms: DNA double helix, histones,
nucleosomes, tight helical fiber, supercoil, eukaryotic chromosome.
16. What are sister chromatids? What is a centromere?
17. What happens to the sister chromatids during cell division?
18. ALERT!!!!! Sister chromatids only occur after DNA replication, when a cell is preparing to divide. During
cell division into two separate daughter cells, the sister chromatids separate into fully separate chromosomes.
Make sure this sentence makes sense to you: “A dividing human skin cell, for example, has 46 duplicated
chromosomes, and each of the two daughter cells that result from it has 46 single chromosomes.” If this
statement does not make sense to you, make note of it here. We’ll come back to this.
19. Do all cells in your body divide? What is the rate of cell division?
20. What is the definition of “cell cycle”?
21. Redraw Figure 8.6 here. Make sure you know this diagram.
22. What happens during interphase? How long does interphase last?
23. Critical Thinking: Think back to our first unit, where we described the structures of a cell (nucleus,
mitochondria, ER, lysosomes, cytoskeleton, etc…). All of these structures must be duplicated using building
blocks transported into the cell. Remember, also, that proteins not only form a part of these structures, but they
also build them and do the work of the cell (enzymes are proteins!). So…in interphase of a dividing cell, the
cell not only goes about doing business as usual, it must also double everything in its cytoplasm. Referring
back to the last reading guide, how do you think the cell accomplishes this incredible task?
24. At what point does the DNA become duplicated in the cell cycle?
25. Think Back: Go back to Ch 10, pg 177, and remind yourself of DNA replication. Write down a brief
description of it here, making sure to use the terms “parental” and “daughter” strands, as well as DNA
polymerase, and which bases pair together.
26. OK, now that the cell has doubled everything in the cytoplasm and has duplicated its DNA, it is now ready
to divide. What phase does actual cell division occur in? What processes occur in this phase? Describe them.
Phase of cell cycle where cell division occurs:
A. Process with description:
B. Process with description:
27. How accurate is this process of dividing the DNA between two daughter cells?
28. Vocabulary to know for understanding mitosis:
What are each of these structures:
Microtubules (pg 69)
Chromosome
Centrioles (glossary)
Sister chromatids
Centrosomes
Centromere
Mitotic Spindle
Daughter chromosomes
Nuclear envelope
Cleavage furrow
Plasma membrane
Cell plate
29. Draw a picture of each stage of mitosis in order to understand how DNA is equally divided into two
daughter cells. Also describe in words what changes are happening to the chromosomes and nucleus and to the
mitotic spindle and cytoplasm during each phase. Remind yourself here about the difference between a
chromosome and sister chromatids.
Draw a picture of a cell at this stage
Changes to the Chromosomes
Changes to the Mitotic
Stage of
and
the
Nucleus
Spindle
and the Cytoplasm
Cell Cycle
Interphase
Prophase
Mitotic phase
Metaphase
Anaphase
Telophase
and
Cytokinesis
30. Why is it important to be able to control the cell cycle?
31. What is the cell cycle control system and how does it control the cell cycle?
32. Critical Thinking: One major role of our immune system is to defend ourselves against invading bacteria
and viruses. These microbes can duplicate themselves at alarming rates, and so, some of the cells of our
immune system (specifically, B cells and T cells) must also duplicate in order to be able to fight off the
invasion. In the last reading guide we thought about how our immune system might detect the presence of
invading viruses or bacteria through signal transduction. Now, using the information you have just learned,
discuss what you think happens to an immune cell once that signal has been transmitted.
33. Critical Thinking: What do you think happens as your skin heals after receiving a cut?
34. Critical Thinking: What do you think happens as the cells that line your digestive tract continually replace
themselves?
35. What is “cancer” in terms of the cell cycle?
36. What is the difference between a “benign tumor” and a “malignant tumor”?
37. What is metastasis?
38. Describe the three most prevalent forms of cancer treatment and what they do to stop the cancer:
1.
2.
3.
39. List the four lifestyle changes from the text that can help prevent cancer:
40. List the six types of cancer that can be easily detected and how they are detected:
Note: Want to know more about cancer? Want to do an extra credit project? Check out pg 211-215 to find out
more. Pick a type of cancer, research it, and present it to the class in a 5 min or less Powerpoint presentation.
Now watch that YouTube video of dividing breast cancer cells again.
http://www.youtube.com/watch?v=Hm03rCUODqg&NR=1&feature=fvwp
41. Critical Thinking: What was happening in each of your observations that you made the first time you
watched this?
To prepare for lab read the short section on PCR:
Chapter 11, pg 227 (PCR)
1. What is PCR? Redraw Figure 12.15 to aid in your description.
3. What enzyme is used in PCR and where have you heard of this enzyme before?