BILD 1 Lecture Notes - Lecture 10: Sister Chromatids, Nuclear Membrane, Cell Plate
Document Summary
Cytokinesis differs for plant and animal cells: vesicles containing cell wall material create a cell plate and then a new cell wall, dividing the daughter cells of plant cells. Interphase: duplicate chromosomes in nucleus, chromosomes consist of two identical copies called sister chromatids. Spindle forms: centrosomes move to opposite sides of the cell, dna becomes more compacted, nuclear envelope starts to break up. Metaphase: the spindle causes chromosomes to line up in the center. Sister chromatids separate and move towards opposite sides of the cell. Telophase: chromosomes become less condensed, new nuclear envelopes form. How many chromosomes are present when two sister chromatids are attached: the answer is one chromosome. If those sister chromatids divide, then we have two chromosomes. Karyotypes are taken at metaphase in a cell. Cell density, and chemical growth factors affect cell division. Factors that control cell division: presence of essential nutrients, growth factors, proteins that stimulate division, presence of other cells causes density-dependent inhibition.
