Download Gregory Mendel (1822-1884), the discoverer of the gene and the

UNIT 6: The Cell Cycle
Unit 6: Cell Cycle
A. Cycle, Replication, Chromosomes
B. Mitosis
C. Meiosis
BIO.B.1.1 Describe the three stages of the cell cycle: interphase, nuclear division,
cytokinesis.
 BIO.B.1.1.1 Describe the events that occur during the cell cycle: interphase,
nuclear division (i.e., mitosis or meiosis), cytokinesis.
 BIO.B.1.1.2 Compare the processes and outcomes of mitotic and meiotic
nuclear divisions.
BIO.B.1.2 Explain how genetic information is inherited.
 BIO.B.1.2.1 Describe how the process of DNA replication results in the
transmission and/or conservation of genetic information.
 BIO.B.1.2.2 Explain the functional relationships between DNA, genes, alleles,
and chromosomes and their roles in inheritance.
cell cycle
DNA replication
chromosomes
mitosis
interphase
cytokinesis
meiosis
gamete
crossing-over
gene recombination
chromosomal mutation
nondisjunction
translocation
Notes and Stuff: Chapter 9
Section 9.1:
1.
Describe how the cell theory is related to this topic (Cell Division)
2. What are the 2 primary functions of cell division? Give examples of each.
3. Explain and give examples of the 2 types of reproduction.
Section 9.2
1. Describe the difference between chromatin, chromosomes and sister chromatids? Use a labeled
drawing to explain.
2. Draw Figure 9-5 from page 183 below:
,2
3. What is occurring during Interphase of the cell cycle?
4. What is occurring during the Mitosis phase of the cell cycle?
3
Overview of the cell cycle
How often a cell divides depends on the type of cell. Some cells divide once a day. Some divide more often; others,
less often. Some highly specialized cells, such as mature muscle cells, do not divide at all. Eukaryotic cells that do
divide undergo an orderly sequence of events known as the cell cycle. The cell cycle extends from the "birth" of a
cell as a result of cell reproduction to the time the cell itself reproduces. Understanding the cell cycle will help you
understand how cells function and how irregularities in the cell cycle can lead to disease.
Interphase The cell may spend as much as 90 percent of the cell cycle in interphase.
Interphase is the stage during which a cell carries out its metabolic processes and
performs its functions. For example, a cell in your stomach lining might be making and
releasing enzyme molecules that help digest your food. During interphase, a cell
increases its supply of proteins, increases the number of many of its organelles (such as
mitochondria and ribosomes), and grows in size.
Interphase also includes cellular functions leading up to cell division. One key event is
the duplication of the DNA in the cell's chromosomes. This period is called the S phase
(S stands for DNA synthesis). The interphase periods before and after the S phase are
called the G1 and G2 phases (G stands for gap). During the G2 phase, each duplicated
chromosome remains loosely packed as chromatin fibers. In humans and other mammals,
cells that reproduce daily have a cell cycle that usually lasts 10 to 20 hours. The S phase
takes about 3 to 6 hours, while the G2 phase is slightly shorter.
Mitotic Phase The stage of the cell cycle when the cell is actually dividing is called the
mitotic phase (M phase). The mitotic phase includes two processes, mitosis and
cytokinesis (Figure 9-6). During mitosis, the nucleus and the duplicated chromosomes
divide and are evenly distributed, forming two "daughter" nuclei. Cytokinesis is the
process by which the cytoplasm is divided in two. Cytokinesis usually begins before
mitosis is completed. The combination of mitosis and cytokinesis produces two
genetically identical daughter cells since the chromosomes were duplicated precisely in
the S phase. Each daughter cell has a single nucleus, some surrounding cytoplasm, and a
plasma membrane.
Mitosis is a very accurate way of distributing identical copies of a large amount of
genetic material to two daughter cells. Experiments with yeast cells, for example,
indicate that an error in chromosome distribution occurs only once in about 100,000 cell
divisions. Mitosis is unique to eukaryotes. Prokaryotes use a simpler mechanism for
distributing DNA to daughter cells.
4
Cell Cycle: The life of a cell
The Beginning:
The most important process that needs to occur for a cell to reproduce is DNA
replication- the process where a strand of DNA makes an exact copy of itself. Below,
show how the following strand of DNA would replicate.
A-T
C-G
G-C
T-A
A-T
G-C
T-A
A- ____
C- ____
G- ____
T- ____
A- ____
G- ____
T- ____
____ - T
____ - G
____ - C
____ - A
____ - T
____ - C
____ - A
What do you notice about the two strands of DNA that you created?
DNA Replication occurs during the longest stage of the cell cycle, called Interphase.
Define the following words:
ChromosomeSister Chromatid(Draw a pair of sister chromatids)
6
Genes are on chromosomes
Long before the structure and importance of DNA was discovered in the 1950s, Walter Sutton, a graduate
student at Columbia University in New York City, and Theodor Boveri, a German zoologist came to the conclusion
that chromosomes passed along traits from parents to offspring. This was in 1902. Sutton and Boveri proposed the
chromosome theory of heredity which states that each gene occupies a specific place on a specific chromosome.
We now know that chromosomes are formed when DNA molecules (chromatin) coil. So a gene is made up of
DNA (as shown on the graphic). The code in this DNA segment directs the making of one protein. We, as humans,
have approximately 28,000 genes contained on our 46 chromosomes in each cell.
1. ____________________ and ______________________ stated the chromosome theory of inheritance
which says ________________________________________________________
__________________________________________________________________________
2. How are chromosomes, genes and DNA related? ______________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Working with Karyotypes
Log onto the following sites and answer the questions concerning karyotypes.
http://learn.genetics.utah.edu/ > Heredity and Traits > How Do Scientists Read Chromosomes?
TAKE THE TIME TO READ THROUGH THE WHOLE TUTORIAL PLEASE!
1.
How do you know what chromosomes go together?
a) ___________________________________________________________________________
___________________________________________________________
b) ___________________________________________________________________________
___________________________________________________________
c) ___________________________________________________________________________
___________________________________________________________
2. Click on Home > Heredity and Traits > Making a Karyotype. Play the animation. THEN complete the
interactive version – print out a copy and put your name on top.
* If you are unable to print the page directly try this: Push the print screen button. Then open a word
document. Edit > Paste the screen into the document and THEN print.
3. Click on Home > Heredity and Traits > What is a Chromosome. Go through this section of the tutorial.
Realize that different organisms have different numbers of chromosomes. How many chromosomes do each
of the following organisms have?
mosquitoes:_________
carp:_________
onions:_________
www.biology.arizona.edu/human_bio/activities/karyotyping/karyotyping.html
4. (1 pt) How many times per year in the US are karytoype analyses performed?
______________
5. (1 pt) What is the banding pattern on chromosomes called?
_____________________________________
6. (2 pts) What is a common misconception about the bands on chromosomes? Explain.
____________________________________________________________________________________
____________________________________________________________________________________
___________________________________________________________
Mitosis Lab: The making of a new cell
8
Directions: Your book describes four steps of mitosis. There are scientific names for the steps. Below, you
are given 5 steps, in order. This includes interphase, which is the stage where the cell is not dividing, but rather
growing, performing cellular functions, and replicating DNA. After each stage, write down the main processes
that occur. Use your book, pages 186 and 187, as a guide.
Phase Name
Interphase
Phase Order
Processes
Main Phase - Cell growth
- DNA replicates
- Centrioles reproduce
1st
Prophase
2nd
Metaphase
3rd
Anaphase
4th
Telophase
Now, go on to the next page to draw each of these steps in plant and animal cells
10
Name:___________________________________Date:______________
Cell Cycle Labeling
11. What moves the chromatids during mitosis? ___________________________________
12. What anchors the spindle? ________________________________________
13. What are the four phases of mitosis? ___________________________________________________
14. How many daughter cells are created from mitosis and cytokinesis? ___________________________
15. During what phase does cytokinesis begin? ________________________________________
16. If a human cell has 46 chromosomes, how many chromosomes will be in each daughter cell? _________
17. If a dog cell has 72 chromosomes, how many daughter cells will be created during a single cell cycle? ______
.....Each of these daughter cells will have how many chromosomes? ____________
18. The nuclear membrane dissolves during what phase? ________________________
19. In the cell pictured above, how many chromosomes are present during prophase? ________________
20. What structure holds the individual chromatids together? ______________________________
12
Meiosis: Double up on mitosis
Below, Draw the steps of meiosis, labeling along with the teacher.
Definitions: Define the following terms based on your notes and/or the book.
Gamete-
Homologous pair-
Diploid cell-
Haploid cell-
Meiosis I-
Meiosis II-
Polar Bodies-
Karyotype-
14
Name: ______________________________________
Date: ________________________
Student Exploration: Cell Division
Vocabulary: cell division, centriole, centromere, chromatid, chromatin, chromosome, cytokinesis, DNA,
interphase, mitosis
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Cells reproduce by splitting in half, a process called cell division. What do cells need to do between
divisions to make sure that they don’t just get smaller and smaller?
_________________________________________________________________________
2. The genetic information of a cell is carried in its DNA (short for deoxyribonucleic acid). What do cells need to
do between divisions to make sure that a full set of DNA gets passed on to each daughter cell?
_________________________________________________________________________
_________________________________________________________________________
Gizmo Warm-up
On the SIMULATION pane of the Cell Division Gizmo™, check that the Cycle
Length is set to 12 hours. Click Play ( ), observe until the maximum number of
cells is shown, and then click Pause ( ).
1. Look at the cells. Do they all look the same? _______________
2. Cells that are in the process of dividing are said to be in mitosis or cytokinesis.
Cells that are not dividing are in interphase.
Check the Magnify box and move the cursor over the cells.
A. Of the 100 cells shown, how many are in the process of dividing? _______________
B. Select the BAR CHART tab, and turn on Show numerical values. How many cells are in the
interphase stage of their life cycle? ______________________________
C. Based on these two observations, would you say that a cell spends most of its life cycle in interphase
or in mitosis/cytokinesis? _______________________________
16
Get the Gizmo ready:
Activity A:
Phases of the cell
cycle
 Click Reset ( ).
 Select the DESCRIPTION tab.
 Click on the right arrow once so that Interphase is
shown.
Question: What are the stages of the cell cycle?
1. Observe: Click Play and hold the cursor over the cell. Observe the cell as it divides several times. (This
happens quickly!) What do you notice happening during this process?
_________________________________________________________________________
_________________________________________________________________________
2. Summarize: On the DESCRIPTION pane, read about each phase in the cell cycle. In the spaces below,
sketch the cell in each phase and summarize what occurs in your own words.
Phase
Sketch
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
(Activity A continued on next page)
Summary
Activity A (continued from previous page)
3. Analyze: Use your summaries and the Gizmo to answer the following questions:
A. What are the four phases of mitosis? _____________________,
_____________________, _____________________, _____________________
B. During which phase is the DNA duplicated? _____________________
C. What is the relationship between chromatin and chromosomes? ______________
___________________________________________________________________
D. In which phase are chromatids pulled apart? _____________________
E. What is the role of the centrioles? _______________________________________
F. In which phase does a new nuclear membrane develop? _____________________
G. A cell has a single line of chromosomes. What is the phase? ___________________
H. During which three phases are individual chromosomes no longer visible?
_____________________, _____________________, _____________________
4. Think and discuss: Why is it important that the cell’s DNA is duplicated before cell division?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
5. Challenge: Human cells have 46 chromosomes. Each chromosome consists of a pair of identical chromatids
attached together by a structure called a centromere. Once the chromosome has split, each chromatid is
called a daughter chromosome. At the end of cytokinesis, how many daughter chromosomes will be found in
each cell? Explain.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
18
Get the Gizmo ready:
Activity B:
 Click Reset.
 Select the TABLE tab.
Duration of
phases
Question: What is the relative duration of each phase of the cell cycle?
1. Collect data: Set the Cycle Length to 10 hours and click Play. Click Pause when the maximum number of
cells has been reached. On the TABLE tab, click Record data.
Record the number of cells in each phase of the cell cycle in the table below. Then click Play, wait for a
while, and click Record data again. Repeat this process until you have recorded four sets of results, and
then find the average number of cells in each phase.
Trial
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
1
2
3
4
Avg.
2. Analyze: Which phase of the cell cycle is longest? ____________ Shortest? ____________
Explain your answers: _______________________________________________________
_________________________________________________________________________
3. Calculate: You can use your data to estimate the duration of each phase of the cell cycle. For example, if 8%
of the cells were in prophase and the cell cycle was 10 hours long, then prophase would last 8% of 10 hours,
or 0.8 hours (48 minutes).
Use percentages to estimate the duration of each phase of the cell cycle. Show your work.
Interphase:
__________________________________________________________
Prophase:
__________________________________________________________
Metaphase:
__________________________________________________________
Anaphase:
__________________________________________________________
Telophase:
__________________________________________________________
Cytokinesis:
__________________________________________________________
Get the Gizmo ready:
Extension:
Cell populations
 Click Reset.
 Select the GRAPH tab.
 Set the Cycle Length to 5 hours.
Question: How quickly do cells multiply?
1. Collect data: Click Play to start a new simulation. Click Pause
when the maximum number of cells is reached. View the total
number of cells on the GRAPH tab. (Click the “–” button until
the whole graph is visible.)
Draw a sketch of this graph here.
What is the general shape of the graph?
____________________________________
____________________________________
____________________________________
2. Analyze: Look closely at the graph.
A. About how long did it take to grow the first 20 cells? __________________________
B. About how long did it take to grow the last 20 cells? __________________________
C. Would you say the rate of cell growth is increasing or decreasing? Explain.
___________________________________________________________________
___________________________________________________________________
3. Extend your thinking: In living organisms, the cell cycle is closely regulated. What do you think will happen if
cell division is not controlled?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
20
Mutations: The mistake that DNA made
Internet Research Lab
Directions: Go to the following website.
http://learn.genetics.utah.edu/archive/mutations/index.html
Hint- you can access this site from a link on my teacher page.
Part I- What is a mutation?
Procedure:
1. Read through “What is a mutation” section.
2. Answer the following questions.
a. What is a codon?
b. How many nucleotides make up a codon?
c. What happens when you read the codons wrong?
3. Click on the “mutate a DNA sequence” link.
4. Read the text highlighted in yellow, on the right side of the page.
5. Define the following types of mutations.
Point mutationsSilent mutation-
Frameshift mutations-
Insertion mutation-
Deletion mutation-
22
Mutations: The mistake that DNA made
Internet Research Lab
Part II- What are Genetic Disorders?
Procedure
1. Either search for the “genetic disorders library” or type in the following link
http://learn.genetics.utah.edu/content/disorders/whataregd/
2. Explore this page and its links to answer the following questions.
Define
Gene3. Answer the following questions.
a. What is Nondisjunction?
i. What is trisomy?
1. Give an example
ii. What is monosomy?
1. Give an example
b. What are Single gene disorders?
i. Give an example
c. What are Multifactoral Disorders?
i. What causes cancer?
d. List three reasons why all mutations don’t cause disorders.
i.
ii.
iii.
Unit VI Cell Cycle
1. Explain the comic from the front page using the appropriate terminology.
a. What is lying on the couch?
b. What was grabbed?
c. What grabbed it?
d. When was it grabbed (two possible answers)?
e. What is it called now? Before the “abduction”?
2. Use the diagram on the next page to complete the following questions.
a. In the white boxes, identify what is occurring on the left and right of the diagram.
b. What is occurring in Process A? What in what part of the cell cycle does this occur?
c. What is letter b and what is occurring in Process B? Why is this important?
d. What does the “2n=4” and “n=2” refer to on the diagram?
e. What is the function of meiosis? How is this different from the function of mitosis?
24
3. Look at the following karyotype.
a. What two things can you tell about this person from the karyotype? Be specific.