Post on 25-Dec-2015
Cell Growth Cell Growth and Divisionand Division
Chapter 10Chapter 10
Limits to cell growth 10-1Limits to cell growth 10-1
1. The larger a cell becomes, 1. The larger a cell becomes, the more demands the cell the more demands the cell
places on its DNA.places on its DNA.
2. The more trouble the cell 2. The more trouble the cell has moving enough nutrients has moving enough nutrients
and wastes across the cell and wastes across the cell membrane.membrane.
DNA overloadDNA overload
• DNA controls the cell’s functionDNA controls the cell’s function
• When a cell is small, the information stored When a cell is small, the information stored in that DNA is able to meet all of the cell’s in that DNA is able to meet all of the cell’s needs.needs.
• As the cell increases in size, it does not As the cell increases in size, it does not make extra DNA and is no longer able to make extra DNA and is no longer able to serve the needs of the growing cell.serve the needs of the growing cell.
Exchanging Exchanging materialsmaterials• Cells must obtain all of their food, oxygen Cells must obtain all of their food, oxygen
and water through their membraneand water through their membrane
• The rate at which food and oxygen are The rate at which food and oxygen are used up and waste produced depends on used up and waste produced depends on the cell’s volumethe cell’s volume
• As cells grow large their ability to obtain As cells grow large their ability to obtain materials through their membrane goes materials through their membrane goes downdown
• Surface area to volume ratioSurface area to volume ratio
Cell Size
Surface Area (length x width x 6)
Volume (length x width x height)
Ratio of Surface Area to Volume
Ratio of Surface Area to Volume in CellsSection 10-1
Go to Section:
As cell volume increases, surface area decreases!
How does the cellhandle overload??
Cell Division 10-2Cell Division 10-2
• DNA is stored in the form of DNA is stored in the form of chromosomeschromosomes– Human cells contain 46 chromosomesHuman cells contain 46 chromosomes– Fruit flies contain 8 chromosomesFruit flies contain 8 chromosomes– C. not visible except during cell divisionC. not visible except during cell division– Each C. is replicated prior to divisionEach C. is replicated prior to division– What you see is identical “sister” chromatidsWhat you see is identical “sister” chromatids– Chromatids are attached in the center by a Chromatids are attached in the center by a
centromerecentromere
Chromosomes
Cell CycleCell Cycle
• Period of time from the beginning of one cell Period of time from the beginning of one cell division to the beginning of the next.division to the beginning of the next.
• G1 phase – cell growth and activityG1 phase – cell growth and activity• S phase – replicationS phase – replication• G2 – time gapG2 – time gap• M phase – mitosisM phase – mitosis
• Interphase – G1, S, G2Interphase – G1, S, G2
M phase
G2 phase
S phase
G1 phase
Figure 10–4 The Cell CycleSection 10-2
Go to Section:
Mitosis
• The process by which the chromosome’s in a cell duplicate themselves and then separates into two identical cells.
• Mitosis is the division of body cells (somatic cells)
• 4 stages of mitosis
InterphaseInterphase Normal cellular Normal cellular
functionfunction DNA get replicatedDNA get replicated Cell prepares for Cell prepares for
cell divisioncell division Chromosomes are Chromosomes are
not visiblenot visible
ProphaseProphase DNA begins to coil DNA begins to coil
upup Chromosomes Chromosomes
become visiblebecome visible Nuclear membrane Nuclear membrane
dissolvesdissolves Centrioles move to Centrioles move to
opposite endsopposite ends
Metaphase Metaphase
Chromosomes Chromosomes meet in the middlemeet in the middle
AnaphaseAnaphase
Chromosomes pull apartChromosomes pull apart
TelophaseTelophase
Cell membrane pinches in (animal cell)Cell membrane pinches in (animal cell) Cell wall begins to form in (plant cells)Cell wall begins to form in (plant cells) Cytokinesis Cytokinesis
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
Centrioles
Chromatin
Interphase
Nuclear envelope
Cytokinesis
Nuclear envelope reforming
Telophase
Anaphase
Individual chromosomes
Metaphase
Centriole
Spindle
CentrioleChromosomes
(paired chromatids)
Prophase
Centromere
Spindle forming
Section 10-2
Figure 10–5 Mitosis and Cytokinesis
Go to Section:
InterphaseInterphase
ProphaseProphase
Metaphase Metaphase
AnaphaseAnaphase
TelophaseTelophase
Telophase Telophase
Prophase Prophase
Metaphase Metaphase
Anaphase Anaphase
Telophase Telophase