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24 Cards in this Set
- Front
- Back
Mitosis
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is cell division that produces identical cells for growth and repair.
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Before cell division the DNA in the original cell is?
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doubled
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Chromosomes
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made of DNA and proteins, these are visible structures
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Centromere
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Waht attatches two identical pieces of DNA
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Sister Chromatid
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Two pieces of identical DNA joined with a centromere
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Pinch
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When Sister Chromatids spread apart in a cell so that it can pinch itself into two cells.
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Mitotic Spindle
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Network of protein fibers that forms and stretches across the cell. The mitotic spindle is what pulls the chromosomes to either end.
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Somatic Cells
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Body Cells. They all have equal numbers of chromosomes. Humans have 46.
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Pairs
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Chromosomes come in pairs, one from each parent.
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Chromosome Number (n)
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Diploid = 2n = Body Cells (2 sets)
Haploid = n = Sperm or Egg Cells (1 Set) |
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1. Interphase
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90% of Existence. Prepares for Cell Division. DNA is copied, but can not be seen, because it has a nuclear envelope around it.
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2. Prophase
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Nuclear Envelope drops off, chromosomes become visible. Mitotic Spindle Forms.
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3. Metaphase
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Sister chromatids are pulled to the "equator" of the cell, where they are lined up in a single row.
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4. Anaphase
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Sister Chromatids seperate and are pulled to opposite poles. Now each chromatid is independant.
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5. Telophase
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Begins when chromatids arrive at poles. Nuclear envelope forms again around each set of chromosomes.
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6. Cytokinesis (animal)
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contractile microfilaments pull the plasma membrane inward and pinches the cell in two.
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6. Cytokinesis (plant)
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Plant cells cannot be pinched because they have a cell wall. They form a cell plate with cellulose and separate the cells that way.
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Apoptosis
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Cells that are destined to die. i.e. Skin in-between fingers and toes.
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Gamete Shuffle
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Meiosis shuffles the alleles during gamete formation (GAMETES = eggs or sperm), and
fertilization produces offspring with unique combinations of alleles. |
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Variation
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By shuffling chromosomes alone, humans can have 8 million different gametes, so two humans can have 64 trillion genetically different kids
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Meiosis vs Mitosis
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Meiosis has two series of divisions, Meiosis 1 and 2
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Meiosis 1
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During meiosis 1, the sister chromatids do not line up across the equator in a single row. Instead, they line up 2 deep, and the sister chromatids are in tact when they are pulled toward the poles.
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Meiosis 2
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During meiosis 2, The sister chromatids line up again in metaphase. This time, they split before they seperate. The cytoplasm then divides again, resulting in 4 haploid cells.
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Zygote
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Fertilized egg. When this is created through fertilization, the diploid number of chromosomes is restored.
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