Dihybrid cross 9 3 3 1 ratio of phenotypes Chi Square Test Goodness of fit o Formula x 2 summation of O E 2 E After determining goodness of fit you ll get a chi squared number P value o Probability from chi square table Degrees of freedom o Number of categories that are independent of each other Df n 1 o Where n total number of categories 9 3 3 1 o 4 categories 3 degrees of freedom Low chi squared numbers indicate a better fit and a higher confidence interval than high chi squared values Members of a pair of chromosomes are called homologues One member is inherited from the mother One member is inherited from the father o The two homologues form a homologous pair The two chromosomes in a homologous pair o Nearly identical in size o Have the same genes o But not necessarily the same alleles Mitosis PMAT Two daughter cells Interphase o G1 S synthesis chromosomes duplicate G2 Mitosis o Prophase Prometaphase o Metaphase o Anaphase o Telophase two new daughter cells Cytokinesis G0 a cell that moves from G1 G0 means that it s done dividing Sister chromatids split from one chromosome are identical Form the x of chromosomes o Held together at the crossing by a centromere n the DNA that you inherited from one of yoru parents since you inherited DNA from two parents your genome is 2n sperm n egg n DNA replication occurs during S phase synthesis In G2 cell is at 4n And then splits so each cell is 2n Mitosis is splitting 4n 2n Centrosomes The polar things that move to opposite sides of the cell Microtubules Some stretch the entire length of the cell Some go from the chromosomes to the centrosomes Separase Comes along and cleaves the glue bonds of the chromosomes o Moves metaphase to anaphase Metaphase Chromatids are lined up at the middle of the cells Anaphase Cells split as soon as the chromosomes start moving Telophase Cytokinesis Cleavage furrow forms and cells become two cells