chapter 10-2 notes cell divisionnewburyparkhighschool.net/stillwagon/biocp/current notes/chapter...
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Chapter 10-2 Notes
Cell Division
I. Background Information
A. One of the major characteristics of living things is the ability to GROW
1. How? Not simply by growing larger but by dividing in half thus, an adult doesn't have bigger cells, they have more cells
You can grow too many cells!!!
Cancer
B. Chromosomes
1. Genetic information is passed on from one generation to the next through chromosomes
2. Every organism has a specific number of chromosomes
a. ex. carrots = 18 chromosomes
b. ex. humans = 46 23 came from MOM & 23 came from DAD
Before Replication
of DNA
After Replication
of DNA
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During normal mitotic cell division, a parent cell having four chromosomes will produce two daughter cells, each containing
1. two chromosomes.
2. four chromosomes.
3. eight chromosomes.
4. sixteen chromosomes.
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3. The chromosomes from Mom and Dad are considered “homologous” (homo means “same”)
4. Chromosomes are not visible in most cells except during cell division
G1 phase G2 phase M phase all of the
above
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Which of the following is a phase in the cell cycle?
1. G1 phase
2. G2 phase
3. M phase
4. all of the above
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The cell cycle is the
1. series of events that cells go through as they grow and divide.
2. period of time between the birth and the death of a cell.
3. time from prophase until cytokinesis.
4. time it takes for one cell to undergo mitosis.
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Cell Cycle
II. Cell Cycle
A. 3 main stages of the cell cycle:
1. Interphase: longest stage; preparation for cell division
2. Mitosis: nucleus divides into 2 nuclei, each with the same number and kind of chromosomes (DNA) as the parent cell
3. Cytokinesis: cytoplasm divides forming 2 distinct cells
B. Cell Cycle Overview
1. Interphase: quite long
a. Most of the cell’s timespent here
2. Cell Division: occurs quickly
a. Why is it important that the nucleus divides in mitosis?
i. It stores the DNA (information of life)
ii. All new cells need this information
iii. Why? – DNA and protein molecules that make up chromosomes are spread throughout the nucleus and are being used by cell
3. Before cell division, each chromosome is replicated (copied)
4. Then at the beginning of cell division (prophase), the chromatin condenses into compact visible “X” structures (chromosomes with sister chromatids)
5. After Chromosome Replication and Beginning of Prophase
a. Each chromosome is made up of 2 identical “sister” chromatids held together by a centromere.
Chromosome beforereplication
Chromosome AFTERReplication…
…
Centromere
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The structure labeled A in Figure 10–2 is called the
1. centromere.
2. centriole.
3. sister chromatid.
4. spindle.15Answer Now
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The structures labeled B in Figure 10–2 are called
1. centromeres.
2. centrioles.
3. sister chromatids.
4. spindles.
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C. Mini-Summary (up to this point)
1. DNA is being used/ giving instructions to make proteins…cell growing
2. Cell gets too big so the cell prepares to divide(mitosis)
3. DNA replicates (chromosome is copied)
4. What are the 3 steps of the cell cycle?
Interphase (G1, S, G2)
Mitosis (very short)
Cytokinesis
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Which of the following represents the phases
of mitosis in their proper sequence?
1. prophase, metaphase, anaphase, telophase
2. interphase, prophase, metaphase,
anaphase, telophase
3. interphase, prophase, metaphase,
telophase
4. prophase, anaphase, metaphase, telophase
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Mitosis
D. Mitosis is one, continuous event, but it can be described as happening in 4 phases:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
Nuclear division
III. Interphase
A. Parts of Interphase
1. G 1 phase—cells grow, makes organellesand proteins –does its normal job/daily functions
2. S phase—DNA is copied
3. G 2 phase— more organelles are produced that are needed for cell division (prepares for mitosis)
G1 phase G2 phase S phase M phase
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When during the cell cycle is a cell’s DNA replicated?
1. G1 phase
2. G2 phase
3. S phase
4. M phase
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Chromatin
Cell
Membrane
Nucleus
Draw and Label
on Notes
B. Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sister chromatids at the end of this phase.
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Chromosomes
Sister chromatids
Centromere
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Which of the following is a phase of
mitosis?
1. cytokinesis
2. interphase
3. prophase
4. S phase
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Copyright Pearson Prentice Hall
Section 10-2ProphaseSpindle
forming
Chromosomes (paired
chromatids)Centromere
Click to Continue
Mitosis
IV. Phases of Mitosis
**Remember, the cell is coming out of Interphase…
A. PROPHASE
1. Longest phase: 50-65% of total time required to complete mitosis
% Time Spent in Each Phase of Cell Cycle
78%
14%
4%
0.8% 0.2%3%
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
2. Chromatin condenses & chromosomes have been copied (S phase of Interphase) & now become visible as “X” structure (2 “sisterchromatids”)
3. Centrioles appear, separate, and move to
opposite sides of the cell
4. Spindle fibers (from centrioles) form and begin connecting to chromosomes at their centromeres
5. Nuclear envelope breaks down and the nucleolus disappears
Spindle forming
CentromereChromosomes(paired chromatids)
Draw and Label
on NotesCentrioles
Early Prophase
0% 0% 0% 0% 0% 0% 0% 0%
Identify the structures labeled X.
1. nucleus
2. cell membrane
3. spindle fiber
4. chromosome
5. centriole
6. daughter cell
7. cytokinesis
8. cytoplasm 15Answer Now
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Centriole
Centriole
Spindle
Mitosis
Metaphase
B. METAPHASE
1. Fibers connect from the poles (end) of the spindle to the centromere of each chromosome
2. Chromosomes line up in the center of the cell (spindle fibers push and pull chromosomes)
Centriole
Spindle
Draw and Label
on Notes
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Individual chromosomes
Anaphase
Mitosis
C. ANAPHASE
1. Centromeres split, causing the sister chromatids to separate, becoming individual chromosomes
2. Chromosomes are pulled apart to oppositeends of the cell (kinetochore microtubulesshorten)
Individualchromosomes
Draw and Label
on Notes
kinetochore
microtubules
shorten
Non-
kinetochore
microtubules
Lengthen
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Identify the structures labeled Y.
1. nucleus
2. cell membrane
3. spindle fiber
4. chromosome
5. centriole
6. daughter cell
7. cytokinesis
8. cytoplasm 15Answer Now
0% 0% 0% 0%
What is the role of the spindle during
mitosis?
1. It helps separate the
chromosomes.
2. It breaks down the
nuclear membrane.
3. It duplicates the DNA.
4. It makes the
chromosomes visible.
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Nuclear envelope reforming
Telophase
Mitosis
D. TELOPHASE
1. Chromosomes uncoil into chromatin (tangle of dense material – no longer rods)
2. New nuclear envelope reforms around the chromatin
3. Spindle breaks apart
4. Nucleolus reappears in each new nucleus
5. The cell starts to pinch in
6. Mitosis ends
Draw and Label
on NotesNucleolus
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Cytokinesis
Cytokinesis
V. CYTOKINESIS – Last phase of cell cycle; division of the cytoplasm (including fluid and organelles)
End Result:
Two daughter cells
with the same
genetic
makeup
A. Animal cells: cell membrane pinches in & divides
1. Animal cells form an actin-myosin contractile ring within the equatorial region of the cell membrane that constricts to form the cleavage furrow.
Cell wallCell plate
B. Plant cells: a cell plate forms (new cell wall)
1. In plant cells, Golgi vesicle secretions form a cell plate or septum on the equatorial plane of the cell wall by the action of microtubules of the phragmoplast.
C. The cleavage furrow in animal cells and the phragmoplast in plant cells are complex structures made up of microtubules and microfilaments that aide in the final separation of the cells into two identicaldaughter cells.
Draw and Label
bottom figures
on Notes
Chromatin
0% 0% 0% 0%
One difference between cell division in
plant cells and in animal cells is that plant
cells have
1. centrioles.
2. centromeres.
3. a cell plate.
4. chromatin.
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A. B. C. D.
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Cell division is represented in Figure 10–1 by the letter
1. A.
2. B.
3. C.
4. D.
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VI. Then the cell returns to Interphase… and the process continues
Label all
phases on
diagram
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Which of the following is a correct statement about the events of the cell cycle?
1. Little happens during the G1 and G2 phases.
2. DNA replicates during cytokinesis.
3. The M phase is usually the longest phase.
4. Interphase consists of the G1, S, and G2 phases.
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0%
0%
0%
0%
List the correct order for
the diagrams.
1. A, C, D, B
2. B, D, C, A
3. C, A, B, D
4. D, A, C, B
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What would a
diagram of the next
step show?
Rank Responses
1
2
3
4
5
6
1
2
3
4
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Interphase
PROPHASE
chromatin
Chromosome (sister chromatids
held together by centromere)
METAPHASE
ANAPHASE
TELOPHASE
Finally… CYTOKINESIS
and back to INTERPHASE
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The two main stages of cell division are
called
1. mitosis and interphase.
2. synthesis and cytokinesis.
3. the M phase and the S phase.
4. mitosis and cytokinesis.
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During which phase of mitosis do the
chromosomes line up along the middle of
the dividing cell?
1. prophase
2. telophase
3. metaphase
4. anaphase
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The cell’s volume increases.It becomes more difficult for the cell to get enoughoxygen and nutrients.
The cell has DNA overload.Each daughter cell receives its own copy of the parent cell’s DNA.
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Which of the following happens when a
cell divides?
1. The cell’s volume increases.
2. It becomes more difficult for
the cell to get enough oxygen
and nutrients.
3. The cell has DNA overload.
4. Each daughter cell receives
its own copy of the parent
cell’s DNA.15Answer Now
1 2 3 4 5 6
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What will the chromosome number of each
daughter cell shown be after mitosis?
1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
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Amoeba Sisters Mitosis Video 10 notes
https://www.youtube.com/watch?v=f-ldPgEfAHI&index=18&list=PLwL0Myd7Dk1F0iQPGrjehze3eDpco1eVz
Two Pictorial Models of the Stages of the Cell Cycle –
Think-Pair-Share
Fill in the Stages of the cell cycle. On the left, the size of the pie is
proportional to the time spent in each phase. On the right, the icons
visually depict what happens at each stage.
G1S
G2
M
G1
SG2
M
Think-Pair-Share
What would happen if the stages of cell division do not occur in order? For example, what would happen if cytokinesis occurs before mitosis?