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31 Cards in this Set
- Front
- Back
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Why do cells reproduce? |
Growth of multi-celled organisms Reproduction of single celled organisms Repair injured tissue Replace worn out cells |
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What is the cell life cycle? |
Mitosis Gap phase 1 Interphase S phase Gap phase 2 |
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What happens in gap phase 1 |
Growth of the cell and preparation for synthesis |
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What is the s phase? |
Synthesis of DNA (replication) |
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Define chromatin |
DNA+ histone proteins |
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Chromosomes are |
Chromatin that had been copied and condensed |
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How do bacteria reproduce? |
Binary fission |
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Define binary fission |
DNA replicates, then one cell divides into two |
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Cell division is |
Necessary for reproduction, growth, and repair in a multicellular body |
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Asexual reproduction |
Results in offspring that are genetically identical to the parent |
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Sexual reproduction |
Combines genetic information from two individuals of opposite mating types to reproduce offspring. Offspring resulting from sexual reproduction ate similar, but now identical to the parents |
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Mitosis |
Occurs in all cells; makes exact duplicate cells |
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Meiosis |
Occurs only in reproductive cells; makes egg or sperm |
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In the human genome, how many chromosomes in all? How many pairs of homologous chromosomes? |
46 pairs in all, 23 pairs of homologous chromosomes |
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Homologous chromosomes |
Similar, one set from mother and one set from father |
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Karyotype |
A picture of all the chromosomes in an organism |
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Haploid |
1 of each chromosome |
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Diploid |
2 copies of every chromosome (have pairs of homologous chromosomes) |
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How is the cell cycle controlled? |
Controlled at checkpoints by regulatory proteins |
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The life of a cell |
Interphase Mitosis Cytokinesis |
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What happens during mitosis? |
Prophase (condensing) Metaphase (aligning) Anaphase (separating) Telophase (reforming) |
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Cytokinesis |
Two complete cells forming |
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Cytokinesis in animal cells |
Cleavage furrow forms in cell membrane By actin microfilament ring Cytoplasm inside separated Daughter cells separate |
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Cytokinesis in plant cells |
No centrosomes in plant cells Cell wall forms between daughter cells |
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Crossing over |
A physical exchange of chromosomal segments between paired paternal and maternal members of homologous chromosomes. Takes place during prophase of meiosis I |
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Independent assortment of chromosomes |
The random distribution of maternal and paternal chromosomes into gametes during meiosis |
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G0 phase |
Resting phase during which the cell withdraws from the cell cycle before the S phase. |
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G1 Phase |
The stage of the cell cycle that follows mitosis and procedes the S phase. Also grows in size |
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G2 phase |
Stage that follows the S phase and procedes mitosis. Serves as a checkpoint ensuring that mitosis will not be launched under inappropriate conditions |
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How is human meiosis different between males and females? |
Females undergo meiosis to produce haploid egg cells. Males undergo meiosis to produce haploid sperm. |
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Bastula |
A hollow, fluid-filled sphere with a single layer of cells on the surface that forms from repeated division of a zygote |
