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mitosis and meiosis
Tags chapter 3 chromosomes and what are they built up of? self replicating DNA and protein complexes in nucleus that has the genes Histones (protein) wrapped in DNA → Nucleosome → protein + DNA → chromatin (condense really tightly) → chromosome haploid (n) ploidy chromosomes set up in nucleus diploid (2n) - 2 matching sets of chromosomes diploid cell every cells except reproductive -2 versions of every chromosome - one from maternal and other from fraternal homologs (have same genes but not identical) centrome specialized chromosomal region which sister chromatids are connected and where spindle fiber attaches too during cell division telocentric at near end metacentric more or less in middle
acrocentric close to end autosomes chromosomes not involved in sex determination (22 pair of autosomes) chromatid help cells in cell division and duplication, formed when cell has to undergo cell division sister chromatids alleles how traits are expressed satellites
nucleolar organizer region (nucleolus), site of ribosomal RNA synthesis Leptotene lone thin chromosomes thicken (time) zygotene synapsis begins when each chromosomes seek out its homologous partner chromosomes clearly visible and begin pairing along synaptonemal complex to form bivalent or tetrad synaptonemal complex what zips the matching chromosomes, aligns homolgs with precision at corresponding genetic regions of each chromosome pair pachytene begins at completion of synapsis crossing over occurs (recombination) ensures any genetic differences have opp to be shuffled to generate increase genetic diversity diplotene
- gap 2 - interval between duplication and start of mitosis, checking quality of replication and correct errors, fixing, repairment kinetochore how chromosomes attach to microtubules structure in centromere region of each chromatid specialized for conveyances contains proteins (act as motors allowing chromosomes to slide along microtubeles)
cytokinesis division of cytoplasm, cleavage of cell by contracting ring of microfilaments reverse events of prophase synapsis homologous chromosomes line up side by side - physical contact with one another DNA exchange between 2 non sister chromatids of homologous pair of chromosomes centrosomes vs centromeres
centrosomes: organelles in eukaryotic cell that serves as organism centre for all microtubeles centromere: central region (constricted of DNA of chromosomes)
