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| Frage | Antworten |
| homologous chromosomes | corresponding chromosomes usually alike in structure and size, and each carries genetic information for the same set of hereditary characteristics |
| diploid | cells that carry two sets of genetic information are (2n) ________ |
| haploid | reproductive cells of eukaryotic organisms may contain a single set of chromosomes (n) |
| centromere | the attachment point for spindle microtubules - the filaments responsible for moving chromosomes in cell division |
| telomere | ________ protect and stabilize the chromosome ends |
| sister chromatids | to prepare for cell division, each chromosome replicates. These two identical copies are called ________ |
| 3. What process leads to the production of sister chromatids, and when does it occur in the cell cycle? | In preparation for cell division, each chromosome replicates creating an identical copy of itself. This occurs during the s phase (for DNA synthesis). |
| 4. Assuming that DNA replication is perfect, why does mitosis guarantee that the daughter cells are genetically identical to the parent cell? | The resulting daughter cells are genetically identical with one another and their parent cell because DNA synthesis in the s phase creates an exact copy of each DNA molecule, giving rise to two genetically identical sister chromatids. Mitosis then ensures that one of the two sister chromatids from each replicated chromosome passes into each new cell. |
| synapsis | a very close pairing association |
| tetrad | each homologous pair of synapsed chromosomes consists of four chromatids called a bivalent or ________ |
| crossing-over | takes place in prophase I, in which homologous chromosomes exchange genetic information. ________ generates genetic variation and is essential for the proper alignment and separation of chromosomes. |
| recombination | creating new combinations of alleles on a chromatid |
| 8. How do the processes of meiosis and fertilization, when performed correctly, guarantee that all individuals of a species have the same number of chromosomes (at the same stage of the life cycle)? | In meiosis, cohesin is protected at the centromeres during anaphase I, and so homologous chromosomes, but not sister chromatids, separate in meiosis I. The breakdown of centromeric cohesin allows sister chromatids to separate in anaphase II of meiosis. |
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