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Homologous pairs of chromosomes
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Contain same types of genes. 44 pairs of chromosomes in humans can be grouped into homologous pairs.
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Diploid body cells
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Cells of humans have two of each type of chromosome and are diploid
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Haploid
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Human gametes have only one of each type of chromosome and are haploid
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Meiosis
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Cell division in which homologous chromosomes separate from each other to produce four haploid daughter cells (eggs or sperm)
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zygote
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When gametes fuse during fertilization, a diploid ZYGOTE is created
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G0 stage
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Resting stage
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Interphase
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Preparation for mitosis
G1 growth stage S synthesis stage during which genetic material of teh cell is duplicated G2 post synthesis gap |
Prophase
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-chromosomes condense (become tightly packed)
-homologous chromosomes pair up and may exchange info(crossing over) -spindle fibers (part of cytoskeleton) start to form -nuclear membrane breaks down |
Crossing over
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Homologous chromosomes pair up and may exchange info
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Metaphase
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-chromosomes line up in A DOUBLE LINE along the equator of the cell
-spindle fibers attatch centromeres to the poles of the cell |
Metaphase
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-chromosomes line up in A DOUBLE LINE along the equator of the cell
-spindle fibers attatch centromeres to the poles of the cell |
Metaphase
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-chromosomes line up in A DOUBLE LINE along the equator of the cell
-spindle fibers attatch centromeres to the poles of the cell |
Anaphase
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One of each pair of homologous chromosomes are pulled to either side of the cell by the spindle fibers
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Telophase
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-nuclear membranes form around the genetic material at either end of the cell
-spindle fibers break down -chromosome de-condense (are held more loosely) -CYTOKINESIS (division of the cytoplasm) occurs -each new cell contains half of the chromosomes of the mother cell (each with two chromatids) |
Cytokinesis
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Division of the cytoplasm
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