click on a lesson name to select. ch.5 cell growth and division 5.1 the cell cycle 5.2 mitosis and...
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Click on a lesson name to select.
Ch.5 Cell Growth and Division
5.1 The Cell Cycle5.2 Mitosis and Cytokinesis5.3 Regulation of the Cell Cycle5.4 Asexual Reproduction5.5 Multicellular life
Cellular Growth
Ratio of Surface Area to Volume
Section 5.1
The Cell Cycle
As the cell grows, its volume increases much more rapidly than the surface area.
The cell might have difficulty supplying nutrients and expelling enough waste products.
Cellular Growth
Transport of Substances
Substances move by diffusion or by motor proteins.
Diffusion over large distances is slow and inefficient.
Small cells maintain more efficient transport systems.
Cellular Growth
Cellular Communications
The need for signaling proteins to move throughout the cell also limits cell size.
Cell size affects the ability of the cell to communicate instructions for cellular functions.
Cellular Growth
The Cell Cycle
Cell division prevents the cell from becoming too large.
It also is the way the cell reproduces so that you grow and heal certain injuries.
Cells reproduce by a cycle of growing and dividing called the cell cycle.
Interphase is the stage during which the cell grows, carries out cellular functions, and replicates.
Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide.
The Cell Cycle
Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.
The Stages of Interphase
The first stage of interphase, G1
The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.
The Second Stage of Interphase, S
The cell copies its DNA in preparation for cell division.
The Third Stage of Interphase, G2
The cell prepares for the division of its nucleus.
Mitosis and Cytokinesis
The Stages of Mitosis
Prophase
The cell’s chromatin tightens.
Sister chromatids are attached at the centromere.
Spindle fibers form in the cytoplasm.
Section 5.2
The nuclear envelope seems to disappear.
Spindle fibers attach to the sister chromatids.
Mitosis and Cytokinesis
Metaphase
Sister chromatids are pulled along the spindle apparatus toward the center of the cell.
They line up in the middle of the cell.
Mitosis and Cytokinesis
Anaphase
The microtubules of the spindle apparatus begin to shorten.
The sister chromatids separate.
The chromosomes move toward the poles of the cell.
Mitosis and Cytokinesis
Telophase
The chromosomes arrive at the poles and begin to relax.
Two new nuclear membranes begin to form and the nucleoli reappear.
The spindle apparatus disassembles.
Mitosis and Cytokinesis
Cytokinesis
In animal cells, microfilaments constrict, or pinch, the cytoplasm.
In plant cells, a new structure, called a cell plate, forms.
Mitosis and Cytokinesis
Cell Cycle Regulation
Normal Cell Cycle
Different cyclin/CDK combinations signal other activities, including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.
Section 5.3
Quality Control Checkpoints
The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong.
Spindle checkpoints also have been identified in mitosis.
Cell Cycle Regulation
Abnormal Cell Cycle: Cancer
Cancer is the uncontrolled growth and division of cells.
Cancer cells can kill an organism by crowding out normalcells, resulting in the loss of tissue function.
Cell Cycle Regulation
Causes of Cancer
The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations.
Various environmental factors can affect the occurrence of cancer cells.
Cell Cycle Regulation
Apoptosis
Programmed cell death
Cells going through apoptosis actually shrink and shrivel in a controlled process.
Cell Cycle Regulation
Stem Cells
Unspecialized cells that can develop into specialized cells when under the right conditions
Cell Cycle Regulation
Embryonic Stem Cells
After fertilization, the resulting mass of cells divides repeatedly until there are about 100–150 cells. These cells have not become specialized.
Cell Cycle Regulation
Adult Stem Cells
Found in various tissues in the body and might be used to maintain and repair the same kind of tissue
Less controversial because the adult stem cells can be obtained with the consent of their donor
Cell Cycle Regulation
1. A2. B3. C4. D
CDQ 1
A. interphase
B. prophase
C. metaphase
D. telophase
Which is the first phase of mitosis?
Chapter Diagnostic Questions
Chapter
1. A2. B3. C4. D
CDQ 2
Chapter Diagnostic Questions
Chapter
A. interphase
B. metaphase
C. anaphase
D. telophase
During what phase do the sister chromatids line up in the middle of the cell?
1. A2. B3. C4. D
CDQ 3
Chapter Diagnostic Questions
Chapter
A. cytokinesis
B. interphase
C. apoptosis
D. mitosis
Which is not a phase of the cell cycle?
1. A2. B3. C4. D
FQ 1
Chapter
Which can more efficiently supply nutrients and expel waste products?
A. larger cells
B. smaller cells
C. cells with lower surface area to volume ratio
D. cells shaped like a cube
1. A2. B3. C4. D
FQ 2
Chapter
At what stage does a cell spend most of its life?
A. cytokinesis
B. interphase
C. mitosis
D. synthesis
1. A2. B3. C4. D
FQ 3
Chapter
What happens in the cell during cytokinesis?
A. The cell grows and carries out normal functions.
B. The cell copies its DNA and forms chromosomes.
C. The cell’s nucleus and nuclear material divide.
D. The cell’s cytoplasm divides.
1. A2. B3. C4. D
FQ 4
Chapter
In what stage of the cell cycle does the cell’s replicated genetic material separate?
A. cytokinesis
B. interphase
C. mitosis
D. prophase
1. A2. B3. C4. D
FQ 5
Chapter
Which diagram shows anaphase?
A. B.
C. D.
1. A
2. B
FQ 6
Chapter
At the end of mitosis the nuclear material is divided and two new cells have formed.
A. true
B. false
1. A2. B3. C4. D
FQ 7
Chapter
What are the “key and ignition” that start the various activities in the cell cycle?
A. chromatin and chromosomes
B. cyclin and CDKs
C. microtubules and spindle fibers
D. protein and ribosomes
1. A2. B3. C4. D
FQ 8
Chapter
Which of these cancer-causing substances or agents is impossible to avoid completely?
A. chemicals such as asbestos
B. food and drinks that the FDA warns may contain carcinogens
C. tobacco and second-hand smoke
D. ultraviolet radiation from the Sun
1. A2. B3. C4. D
FQ 9
Chapter
What is the term for the programmed death of cells that are damaged beyond repair or have harmful changes in their DNA?
A. apoptosis
B. carcinogens
C. cytokinesis
D. mitosis
1. A2. B3. C4. D
FQ 10
Chapter
Which cells are not locked into becoming one particular kind of cell and are capable of developing into specialized tissues?
A. apoptotic cells
B. cancer cells
C. prokaryotic cells
D. stem cells
1. A2. B3. C4. D
CAQ 1
Chapter
This cell has completed what stage of mitosis?
A. anaphase
B. interphase
C. metaphase
D. telophase
1. A2. B3. C4. D
CAQ 2
Chapter
What term is used to describe programmed cell death?
A. apoptosis
B. anaphase
C. necrosis
D. cyclins
1. A2. B3. C4. D
CAQ 3
Chapter
What is the role of cyclins in a cell?
A. to control the movement of microtubules B. to signal for the cell to divide C. to stimulate the breakdown of the nuclear
membraneD. to cause the nucleolus to disappear
1. A
2. B
3. C
STP 1
Chapter
Which cell has the lowest ratio of surface area to volume?
AB
C
1. A2. B3. C4. D
STP 2
Chapter
At what stage of interphase does the cell take inventory and make sure it is ready for the division of its nucleus?
A. G1
B. S
C. G2
D. M
1. A2. B3. C4. D
STP 3
Chapter
Which occurs in plant cells but not animal cells during the cell cycle?
A. formation of a cell plate
B. formation of microtubules
C. formation of a cleavage furrow at the equator of the cell
D. movement of chromosomes to the poles of the cell
1. A
2. B
STP 4
Chapter
Standardized Test Practice
Multiple changes in DNA are required to change an abnormal cell into a cancer cell.
A. true
B. false
1. A2. B3. C4. D
STP 5
Chapter
Standardized Test Practice
Which is not a condition that can result in cancer?A. a failure in the control mechanisms that regulate
the cell cycleB. a failure in the repair systems that fix changes
or damage to DNAC. a failure of the spindle fibers to move chromosomes
during mitosis
D. mutations or changes in segments of DNA that control protein production