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27 Cards in this Set
- Front
- Back
3 types of fibers in cytoskeleton |
Microtubules (thickest)
Intermediate filaments
Microfilaments (thinnest, also called actin filaments) |
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Site of synthesis of ribosomes |
Nucleolus |
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DNA complexed with proteins (called histones) |
Chromatin |
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How many chromosomes are in a human somatic cell? |
46 |
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How many chromosomes are in a human reproductive (germ) cell? |
23 |
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What proteins complex with DNA to form nucleosome? |
Histones |
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What is the order of the phases of cell division? |
Interphase Prophase Prometaphase Metaphase Anaphase Telophase |
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What occurs during G1 of Interphase? |
Initial growth phase. DNA and protein are made. Increase in organelles and cytoskeleton. Cell doubles in size. |
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What occurs during S phase of Interphase |
DNA replicates |
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What occurs during G2 phase of Interphase? |
Preparation for division. RNA and protein are made. Apoptosis occurs. |
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What is the purpose of Mitosis? |
Growth and repair of cells |
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Prophase |
Chromatin coil to form chromosomes (chromosomes consist of 2 sister chromatids that contain identical DNA)
Nucleoli disappear
Nuclear membrane still intact
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Centrosomes |
Organize microtubules of spindle apparatus |
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Centromeres |
Regions where chromatids are held together |
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Kinetochore |
Protein structure on chromatids where spindle fibers attach, located on centromere region |
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Prometaphase |
Nuclear envelope breaks down
Microtubules invade nucleus and interact with chromosomes, which are more condensed
Still 2 sister chromatids
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Metaphase |
Chromosomes line up with centromeres in a plane (metaphase plate) in center of spindle apparatus
Chromosomes still consist of 2 sister chromatids
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Anaphase |
Sister chromatids separate to opposite poles
Spindle fibers attach to centromere/kinetochore and pull apart chromatids by splitting centromere
Sister chromatids are now called chromosomes |
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Telophase |
2 daughter nuclei reorganize
Spindle disperses, nuclear envelope and nucleoli reform
Chromatin becomes less tightly coiled
2 genetically identical nuclei are seen, each chromosome has 1 DNA molecule
Cytokinesis is underway |
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Cytokinesis for Animals and Protozoans |
Pinching in of nuclear membrane forms cleavage burrow |
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Cytokinesis for Plants, Fungi, and Algae |
Vesicles containing cell wall material fuse along the midline and continues cell wall is formed |
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What is restriction point for cell division? |
G1 in interphase |
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Cancer cells |
do not respond to normal regulation of growth and division |
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Benign tumor |
Not cancerous |
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Malignant Tumor |
Cancerous, may impair functions of organs |
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Growth factor |
A proteins released by by certain body cells that stimulates other cells to divide |
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Density-dependent inhibition of cell division |
Crowded cells usually stop dividing (doesn't happen in cancer cells) |