End Show Slide 1 of 38 Copyright Pearson Prentice Hall 10-1 Cell Growth and Division As the length...
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End Show Slide 1 of 38 Copyright Pearson Prentice Hall 10-1 Cell Growth and Division As the length of a cell increases, its volume increases faster than its surface area. The resulting decrease in the cell’s ratio of surface area to volume makes it more difficult for the cell to move needed materials in and waste products out. Imagine that these are cells. Which cell(s) would have the largest surface area to volume ratios? a. Smallest (6:1), b. Medium (3:1), c. Largest (2:1)
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Transcript of End Show Slide 1 of 38 Copyright Pearson Prentice Hall 10-1 Cell Growth and Division As the length...
End Show
Slide 1 of 38
Copyright Pearson Prentice Hall
10-1 Cell Growth and Division
As the length of a cell increases, its volume increases faster than its surface area.
The resulting decrease in the cell’s ratio of surface area to volume makes it more difficult for the cell to move needed materials in and waste products out.
Imagine that these are cells. Which cell(s) would have the largest surface area to volume ratios?
a. Smallest (6:1), b. Medium (3:1), c. Largest (2:1)
End Show
Slide 2 of 38
Copyright Pearson Prentice Hall
10-1 Cell Growth and Division
A town analogy – why a small cell functions better than a grown one
A small town has a library with a few thousand books. If the town grows, there are more people borrowing books, and some people may need to wait to borrow titles. Similarly, a large cells would have to make greater demands on its available genetic ‘library.’ In time, the town would no longer be able to serve the increasing needs of the growing cell.
What if the town has a two lane main street? As the town grows, more people use the street. The main street, however has not increased in size. Traffic results. A cell is similar. If it is too large, it is more difficult to get sufficient oxygen and nutrition in and waste out.
This is why cells do not grow larger, even though the organism will
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Slide 3 of 38
Copyright Pearson Prentice Hall
10-1 Cell Growth and Division
Cell division A cell divides into two new daughter cells.
Before cell division:•The cell replicates (copies) its DNA so each new daughter cell gets one set of genetic information
Each new cell:•Gets a copy of the genetic “library”•Has an increased ratio of surface area to volume (efficiency)
Slide 4 of 37
End Show
10- Cell Division
Mitosis Rap
•https://www.youtube.com/watch?v=pOsAbTi9tHw
Dramatic Video
•http://youtu.be/Q6ucKWIIFmg
Amoeba Sisters
•https://www.youtube.com/watch?v=gwcwSZIfKlM
Copyright Pearson Prentice Hall
End Show
10-2 Cell Division
Slide 5 of 38
Copyright Pearson Prentice Hall
In eukaryotes, cell division occurs in two major stages:
1st Stage – mitosis: division of the cell nucleus
2nd Stage – cytokinesis: division of cell cytoplasm
Cell Division
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10-2 Cell Division
Slide 6 of 38
Chromosomes
Chromosomes
Genetic information is passed from one generation to the next on chromosomes.
Before cell division, each chromosome is duplicated, or copied.
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10-2 Cell Division
Slide 7 of 38
Chromosomes
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End Show
10-2 Cell Division
Slide 8 of 38
Copyright Pearson Prentice Hall
Chromosomes
Each chromosome consists of two identical “sister” chromatids.
Each pair of chromatids is attached at an area called the centromere.
Sister chromatids
Centromere
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10-2 Cell Division
Slide 9 of 38
Copyright Pearson Prentice Hall
Chromosomes
When the cell divides
–The chromatids separate.
–Each new cell gets one chromatid.
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10-2 Cell Division
Slide 10 of 38
Copyright Pearson Prentice Hall
The Cell Cycle
Cell Cycle
A series of events that cells go through as they grow and divide.
Interphase is the period of growth that occurs between cell divisions.
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10-2 Cell Division
Slide 11 of 38
Copyright Pearson Prentice Hall
The Cell Cycle
During the cell cycle:
• a cell grows (interphase)
• prepares for division
• divides to form two daughter cells, each of which begins the cycle again
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10-2 Cell Division
Slide 12 of 38
Copyright Pearson Prentice Hall
The Cell Cycle
The cell cycle consists of four phases:
• G1 (First Gap Phase)
• S Phase
• G2 (Second Gap Phase)
• M Phase
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10-2 Cell Division
Slide 13 of 38
Copyright Pearson Prentice Hall
Events of the Cell Cycle
Events of the Cell Cycle
During G1, the cell
• increases in size
• synthesizes new proteins and organelles
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10-2 Cell Division
Slide 14 of 38
Copyright Pearson Prentice Hall
Events of the Cell Cycle
During the S phase,
• chromosomes are replicated
• DNA synthesis takes place
Once a cell enters the S phase, it usually completes the rest of the cell cycle.
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10-2 Cell Division
Slide 15 of 38
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Events of the Cell Cycle
The G2 Phase (Second Gap Phase)
• Produces organelles and molecules required for cell division
• Once G2 is complete, the cell is ready to start the M phase—Mitosis
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10-2 Cell Division
Slide 16 of 38
Copyright Pearson Prentice Hall
Cell Cycle
Events of the Cell Cycle
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10-2 Cell Division
Slide 17 of 38
Copyright Pearson Prentice Hall
Mitosis
Mitosis
Biologists divide the events of mitosis into four phases: (PMAT)
• Prophase
• Metaphase
• Anaphase
• Telophase
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10-2 Cell Division
Slide 18 of 38
Copyright Pearson Prentice Hall
Mitosis
Mitosis
End Show
10-2 Cell Division
Slide 19 of 38
Copyright Pearson Prentice Hall
Section 10-2ProphaseSpindle
forming
Chromosomes (paired
chromatids)Centromere
Click to Continue
Mitosis
Prophase
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10-2 Cell Division
Slide 20 of 38
Copyright Pearson Prentice Hall
Mitosis
Prophase
• 1st phase
• longest phase
• nucleolus disappears
•centrioles separate and take up positions on opposite sides of the nucleus.
Spindle forming
CentromereChromosomes(paired chromatids)
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10-2 Cell Division
Slide 21 of 38
Copyright Pearson Prentice Hall
Mitosis
The centrioles lie in a region called the centrosome.
The centrosome helps to organize the spindle, a fanlike microtubule structure that helps separate the chromosomes.
Spindle forming
CentromereChromosomes(paired chromatids)
centrioles
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10-2 Cell Division
Slide 22 of 38
Copyright Pearson Prentice Hall
Mitosis
• Chromatin condenses into chromosomes.
• The centrioles separate and a spindle forms.
• The nuclear envelope breaks down.
Spindle forming
CentromereChromosomes(paired chromatids)
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10-2 Cell Division
Slide 23 of 38
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Centriole
Centriole
Spindle
Mitosis
Click to Continue
Metaphase
Metaphase
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10-2 Cell Division
Slide 24 of 38
Copyright Pearson Prentice Hall
Mitosis
Metaphase
• 2nd phase
• Chromosomes line up across the center of the cell (equator).
• Microtubules connect the centromere of each chromosome to the poles of the spindle.
Centriole
Spindle
Microtubules
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10-2 Cell Division
Slide 25 of 38
Anaphase
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Individual chromosomes
Anaphase
Mitosis
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10-2 Cell Division
Slide 26 of 38
Copyright Pearson Prentice Hall
Mitosis
Anaphase
• 3rd phase.
• Sister chromatids separate into individual chromosomes.
• Chromosomes continue to move until they have separated into two groups.
Individualchromosomes
(sister chromatids)
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10-2 Cell Division
Slide 27 of 38
Telophase
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Nuclear envelope reforming
Telophase
Mitosis
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10-2 Cell Division
Slide 28 of 38
Copyright Pearson Prentice Hall
Mitosis
Telophase
• Final phase
• Chromosomes gather at opposite ends of the cell and lose their distinct shape.
• A new nuclear envelope forms around each cluster of chromosomes.
Chromosomes
Nuclear envelope
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10-2 Cell Division
Slide 29 of 38
Copyright Pearson Prentice Hall
Cytokinesis
Cytokinesis
Cytokinesis
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10-2 Cell Division
Slide 30 of 38
Copyright Pearson Prentice Hall
Cytokinesis
•The cytoplasm pinches in half.
• Each daughter cell has an identical set of duplicate chromosomes
Duplicate chromosomes
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10-2 Cell Division
Slide 31 of 38
Copyright Pearson Prentice Hall
Cytokinesis in Plants
In plants, a structure known as the cell plate forms midway between the divided nuclei.
Cell wallCell plate
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10-2 Cell Division
Slide 32 of 38
Interest Grabber
Knowing When to Stop
Suppose you had a paper cut on your finger. Although the cut may have bled and stung a little, after a few days, it will have disappeared, and your finger would be as good as new.
1.How do you think the body repairs an injury, such as a cut on a finger?
2. How long do you think this repair process continues?
3. What do you think causes the cells to stop the repair process?
Copyright Pearson Prentice Hall
The cut is repaired by the production of new cells through cell division.
Cell division continues until the cut is repaired.
When the cut is filled in, there is no room for more cells to grow
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Slide 33 of 38
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(must have QuickTake software installed on the computer you are using for this presentation)
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10-2
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Slide 34 of 38
Copyright Pearson Prentice Hall
10-2
The series of events that cells go through as they grow and divide is called
a. the cell cycle.
b. mitosis.
c. interphase.
d. cytokinesis.
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Slide 35 of 38
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10-2
The phase of mitosis during which the chromosomes line up across the center of the cell is
a. prophase.
b. metaphase.
c. anaphase.
d. telophase.
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Slide 36 of 38
Copyright Pearson Prentice Hall
10-2
Cytokinesis usually occurs
a. at the same time as telophase.
b. after telophase.
c. during interphase.
d. during anaphase
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Slide 37 of 38
Copyright Pearson Prentice Hall
10-2
DNA replication takes place during the
a. S phase of the cell cycle.
b. G1 phase of the cell cycle.
c. G2 phase of the cell cycle.
d. M phase of the cell cycle.
End Show
Slide 38 of 38
10-2
During mitosis, “sister” chromatids separate from one another during
a. telophase.
b. interphase.
c. anaphase.
d. metaphase.
