Oakton College

Syllabus BIO 101-011






1)      Chromatin – strands of DNA in nucleus during Interphase


2)      Sister chromatids = two half’s of a chromosome


3)      Chromatids = 2x # of chromosomes / one half of a replicated chromosome


4)      Chromosome = coiled up DNA that passes genes on the DNA to daughter cells when the cell divides


  1. most visible during mitosis/meiosis


5)      Centromere – middle of a sister chromatid


i.      Divides at onset of Anaphase in Mitosis and Anaphase II in Meiosis


6)      Spindle fibers – what pull chromosomes apart during cell division


7)      Cleavage furrow – bit of cleavage that animal cells make when dividing


8)      Diploid (2n) – cell containing 2 homologous sets of chromosomes, one from each parent


i.      Reproduces sexually


ii.      What all cells have except egg + sperm


iii.      Double the haploid


9)      Haploid (n) – half the Diploid # of genes, is the egg + sperm cells


10)  Dyad = 2 chromatid


11)  Tetrad = 4 chromatid (Haploid #)


12)  Crossing over – when chromosomes exchange segments to rearrange genetic information during Prophase I of Meiosis


13)  Homologous chromosomes – 2 chromosomes making up matched pair in a diploid cell


  1. Same length, centromere position, and staining pattern
  2. Possess genes for same traits at corresponding loci
  3. 1 from father, 1 from mother


14)   Autosomes – chromosome not involved in determining an organism’s sex


15)  Sex chromosomes – determine organism’s sex


16)  Gametes – reproductive cells (egg/sperm)


17)  Chiasmata – microscopically visible site where crossing over has occurred between chromatids of homologous structures during Prophase I of Meiosis


18)  Somatic cell – typical body cell


19)  Karyotype – micrographs of the metaphase chromosomes of a cell (nucleus)


20)  Karyokinesis – division of nucleus


21)  Gametogenesis – creation of gametes within gonads


22)  OOgenesis – creation of mature egg cells


23)  Spermatogenesis – creation of sperm cells


24)  Polar bodies – byproducts of primary/secondary oocyte at each point of meiotic division in oogenesis (not in spermatogenesis)


25)  Girls are born with their eggs already made in Prophase I; puberty comes during Metaphase II


26)  Prophase is longest phase of Meiosis


27)  Klinefelters – XXY (when a male has an extra X chromosome)


28)  Metafemale – XXX (when a female has an extra X chromosome)


29)  Turners Syndrome – X0 (45 chromosomes in female, where they lack another X chromosome)


30)  Not viable – Y0


31)  Mitosis – growth/repair


  1. One diploid parent cell divides to form 2 genetically identical daughter cells
  2. Used for asexual reproduction in unicellular organisms
  3. Cell cycle = 90% Interphase, 10% Mitotic phase
  4. Interphase


i.      G1cell grows + carries out  normal metabolism; organelles duplicate


ii.      S – DNA replication + chromosome duplication


iii.      G2 – construction of spindle apparatus; chromosomes condense; cell continues growing


  1. Prophase – nuclear envelope + nucleoli disappear


i.      Spindle fibers begin to form


ii.      Chromosomes begin to supercoil and are visible for 1st time


iii.      Centrosome head to poles of cell


  1. Metaphase


i.      Spindle fibers fully formed


  1. Attached to all of the kinetochores


ii.      Centrosome are on polar sides of cell


  1. Anaphase


i.      Sister chromatids pulled apart at centromere by spindle fibers retracting, resulting in 1 member of each sister chromatid pair moving into a new cell


  1. Telophase


i.      2 daughter cells have clear body


ii.      Spindle fibers start disappearing


iii.      Nucleoli reappears


iv.      Chromosomes uncoil


  1. Cytokinesis – division of the cell/cytoplasm to form 2 separate daughter cells


i.      Cleavage furrow forms


32)  Meiosis – egg/sperm (sexual cell division)


  1. One parent cell (2n) divides to form 4 haploid daughter cells which are then processed into gametes
  2. Meiosis I – homologous chromosomes separate


i.      Interphase I – chromosomes duplicates à each chromosome has 2 genetically identical sister chromatids


ii.      Prophase I – crossing over occurs à tetrad forms as a result of synapsis


iii.      Metaphase I – spindle microtubules attached to a kinetochore


iv.      Anaphase I – sister chromatids remain attached à homologous chromosomes separate toward 2 poles of cell


v.      Telophase I + Cytokenesis – cleavage furrow forms


  1. Meiosis II – sister chromatids separate during Anaphase II