Structures forming at the centromeres of each chromosome during mitosis for binding the spindle microtubules.

Consists of the combined G1, S and G2 phases of the cell cycle. The period between one mitosis and the next. There are also other 'non-histone' proteins associated with DNA. There are five types - H1, H2A, H2B, H3 and H4. Small, very basic proteins forming complexes with eukaryotic DNA. As the four strands separate, crossover points (chiasmata) become visible between non-sister chromatids resulting in genetic recombination.Ī haploid cell specialised for fertilisation. The fact that each chromosome in a synapsed pair is itself made up of two identical DNA molecules (sister chromatids) now becomes more obvious as the synaptonemal complex dissolves and the synapsed structures now appear as bundles of four chromatids - the tetrad. Further contraction and condensation of the diplotene chromosomes take place to form compact and easily moved structures. The fifth and final stage of meiotic prophase I. The process of cell division following mitotic nuclear divisoin and chromosome segregation. Molecules of DNA complexed with specific proteins responsible in eukaryotes for storage and transmission of genetic information. The name for the protein/DNA complex that makes up the chromosomes. Several chiasmata may occur per bivalent.Įach of a pair of identical DNA molecules complexed with chromosomal proteins and joined at the centromere after DNA replication and before mitosis. between bivalents) and therefore of homologous (non-random) recombination. The visible signs of genetic crossing-over between chromosomes that have paired at meiosis (i.e. The centrosomes move to either side of the nucleus during prophase and, as the nuclear envelope breaks down, form the two poles of the mitotic spindle. The centromere contains highly repetitive, AT-rich DNA sequences.Ī region of the cell cytoplasm adjacent to the nucleus that duplicates during interphase and which contains the centrioles, which organize the spindle microtubules.

Cells may leave the cell cycle after mitosis and enter a state of quiescence called G0.Ī region of the chromosome where the two sister chromatids are held together after DNA replication and chromosomal condensation and which is the attachment point for the mititoc spindle. The cell cycle is divided into four phases: G1 (a preparation phase for DNA replication) S (during which DNA replicates) G2 (a short gap phase during which the DNA is checked for structural integrity), and M - mitosis. The biochemical events that occur between one mitotic cell division and the next in a dividing population of eukaryotic cells. Cytokinesis (cell division) begins during late anaphase.Ī pair of homologous chromosomes during synapsis at the first meiotic prophase and metaphase. Each chromatid is now a chromosome in its own right. The third stage of mitosis when the kinetochores separate and the sister chromatids are pulled towards the opposite poles of the spindle. Terms to know about Mitosis and Meiosis anaphase

During prophase