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| the transmission of traits from one generation to the next. |
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| Offspring differ somewhat in appearance from siblings and parents. |
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| The scientific study of heredity and variation. |
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| Parents endow offspring with coded information in these hereditary units. |
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| Copies of a parent cell's genes are passed along in these sex cells, which are haploid in sexual reproduction. |
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| Organisms that produce offspring which are exact copies of themselves called clones |
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| The progeny of an asexual organism which is an exact copy of itself. |
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| When two parents give rise to offspring tha thave unique combinations of genes inherited from the two parents. |
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| The generation-to-generation sequence of stages in the reproductive history of an organism. |
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| Any cell other than a gamete which, in humans, has 46 chromosomes. |
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| Images of the chromosomal make-up of an organism lined up, pair by pair numbered by size and including the sex chromosomes. |
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| The two copies of the same chromosome. They carry the same genetic information and have the same length and staining in a karyotype. |
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| The X and Y chromosomes which determine the sex of an organism. |
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| The other 22, non-sex, chromosomes. |
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| Any cell with 2 chromosome sets. |
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| Gametes (sperm and egg cells) which have one half the autosomal amount of DNA or chromosomes. |
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| The union of gametes (sperm and egg cells) which result in a return to the diploid number of chromosomes. |
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| The fertilized egg which results from the joining of the egg and sperm ceels during fertilization. |
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| Cell division which reduces the number of chromosomes in half for fertilization so too much genetic information does not collect. |
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| Alternation of generations |
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| The constant change from the haploid to the diploid condition over and over thru generations. |
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| The first round of cell division which includes three differences from the autosomal cell division called mitosis. |
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| The second round of cell division in sex cells which reduces the number of chromosomes from 2 sets to 1. |
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| DNA replicates creating two identical sister chromatids connected at a centromere. Also, the centrosome replicates. |
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| Occupies more than 90% of the time spent in meiosis. Chromatin begins to condense into chromosomes, homnologous chromosomes loosely pair aligned gene by gene, crossing over occurs between two non-sister chromatids, synapsis occurs which holds the two homologues tightly together, the tetrad is formed with one or more chiasmata (regions where crossing over has occured), the centrosomes move to opposite poles and the spindle is formed with microtubules finally, the kinetechores attach to the microtubules. |
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Definition
| The tetrads, or pairs of hologous chromosomes, line up at the equator also called the metaphase plate. the kinetochore of one centromere attaches to the microtubules on one end of the cell while the other kinetochore attaches to the microtubules from the other centrosome. |
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| The chromosomes move towards the opposite poles pulled apart by the microtubules, sister chromatids remain attached at the centromere. |
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| Each half of the cell has a haploid set of chromosomes made up of two sister chromatids, division of the cytoplasm occurs simultaneaously by way of a cleavage furrow in animal cells and a cell plate in plant cells. There is NO replication! |
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Definition
| Spidle apparatus forms like in Prophase 1, the connected sister chromatids move towards the metaphase plate. |
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| Chromosomes line up at the metaphase plate, the kinetochoresof each seaster chromatid attach to microtubules of the spindle in preparation for Anaphase. |
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Definition
| The sister chromatids begin their move to opposite poles. |
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Definition
| Nuclei form surrounding the newly moved haploid set of chromosomes at either pole of the cell, the centrosome and spindle begin to dissolve, the cleavage furrow deepens and four daughter cells are created which are genetically unique from each other and the parent cell. |
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Term
| The three differences between mitosis and meiosis |
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Definition
| 1. Synapsis (pairing up of homologues gene by gene) and crossing over which introduces variation, Prohase 1 2. Tetrads at the metaphase plate,Metaphase 1 . 3. Separation of homologues, Anaphase 1. |
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Definition
| 1. The independent assortment of chromosomes, crossing over and random fertilization. |
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