Unit 4: SAC 1: Hereditry, mitosis. Flashcards
Describe the G1 stage of interphase.
The first part of interphase, the G1 stage develops cell organelles and the cell becomes visibly larger. Normal cell process’ begin.
Describe the S(synthesis) stage of interphase.
After the G1 stage, the S stage takes place in which DNA replication occurs the cells centrosome is duplicated.
Describe the G2 stage of interphase.
The G2 stage allows for continued cellular processes to occur. The newly replicated DNA is checked for mistakes and the chromosomes begin to condense (super coil) and prepare for mitosis.
What is mitosis?
The nuclear division of a parent cell to form two new daughter cells.
Describe early prophase.
The nuclear membrane disintegrates, nucleolus disappears and the chromatin condenses into visible chromosomes.
Describe late prophase.
The chromosomes continue to coil and appear as double chromatids that are joined by a centromere. Centrosomes then move to opposite poles of the cell and form spindle between the poles.
Describe metaphase.
During metaphase, with the help of spindle fibres the chromosomes become aligned at the equator of the cell.
Describe early anaphase.
The chromosomes are pulled to opposite poles of the cell with each chromatid now considered to be a chromosome.
Describe late anaphase.
By late anaphase, the chromosomes have moved to opposite poles. By the end of this stage the two poles have equivalent and complete collections of chromosomes.
Describe Telophase.
Nuclear membrane reforms with nuclei and the chromosomes uncoil back into chromatin.
Describe cytokinesis.
2 new nuclei move apart and the cell separates.
