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17 Cards in this Set
- Front
- Back
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The cell cycle consists of
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Mitotic (M) phase (mitosis and cytokinesis)
Interphase (cell growth and copying of chromosomes in preparation for cell division) |
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The cell cycle is
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the life cycle of individual cells
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Cells are initiated by
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the division of a mother cell
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as parts of a plant reach their final form most cells stop dividing
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cell cycle arrest
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G1 phase (gap 1)
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The cell is recovering from division
It conducts most of its normal metabolism Nucleotides are synthesized, to be used for DNA replication After cell cycle arrest, a cell may stay in a state similar to G1 for life |
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S phase (synthesis phase)
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Genes in the nucleus are replicated
Thousands of genes are attached in a linear sequence The entire structure is a chromosome, each of which is replicated Most plants have between 5 and 30 chromosomes Histones complex with DNA and give it both protection and structure |
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G2 phase (gap 2)
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After S phase, cells enter G2 phase in preparation for division
The proteins necessary for spindle microtubules are synthesized The cell produces proteins for processing chromosomes and breaking down the nuclear envelope After G2 division can occur |
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Division of the nucleus is
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karyokinesis
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Division of the cytoplasm is
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cytokenesis
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Mitosis is called
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It occurs as the body grows and increases in cell number
The nuclear genes are copied One set of genes is separated from the other Each is packed into its own nucleus Sister chromatids are separated into daughter cells in four phases |
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Prophase
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Chromosomes condense by coiling
The nucleolus becomes invisible The nuclear envelops breaks into vesicles The spindle, composed of microtubules coming from opposite poles, attaches to a protein layer on each chromatid: The kinetochore |
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Metaphase
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Microtubules push and pull the chromosomes toward the cell center to form the metaphase plate
At the end of metaphase, enzymes break down the connection between chromatids |
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Anaphase
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Spindle microtubules shorten and pull the twin chromatids toward opposite poles of the cell
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Telophase
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As the chromatids reach each pole of the cell, the nuclear envelope returns and surrounds the group of chromatids
Chromosomes uncondense New nucleoli appear The spindle depolymerizes and disappears |
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CYTOKENESIS:
No matter how the protoplast divides, each half typically contains : |
Mitochondria
Plastids ER Vacuoles, etc |
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During prophase, the preprophase band forms
just inside the plasma membrane |
Identifies the plane of division
Marks the region where the new cell wall will attach to the existing wall |
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phragmoplast
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is a set of short microtubules aligned parallel to the spindle microtubules
It forms in the center of the cell Phragmoplast microtubules trap Golgi vesicles These fuse into a large, flat, plate-like vesicle in which two new primary walls begin to form |
