mitosis

• Mitotic spindle is made up of microtubules
• Centrioles are involved in the formation of cilia and flagella, as well as the organization of the mitotic spindles during cell division.
• The centrosome contains two centrioles that organize the microtubule fibers into the mitotic spindle.
• Chromosomes are condensed forms of DNA that are counted by their centriosomes
• Sister chromatids are two duplicated of condensed DNA
• Centrosomes are the constrictive region that joins two sister chromatids in a chromosome
• Kineticore proteins attach to centrosomes and shorten microtubules (--> tubilent protein sub-units) with the support of motor-proteins that move them along
• Cohesin are loops of protein that initially hold sister chromatids together
• Chromatins are complexes of DNA and histone proteins

  
• Mitosis is needed because an a-nulceated cell cannot synthesize polypeptides to self-maintain the cell so this process is to create duplicate molecules
• Mitosis is asexual reproduction
• Interphase is the normal cycle of the cell- it is where the cell acquires nutrients, creates and uses proteins and other molecules, and starts to prepare for cell division by replicating DNA
• Prophase is where the DNA is still visible as it forms nucleosomes, chromatins, then a chromosome. The nuclear membrane starts to visibly dispate as centrosomes are formed by the centrosomes and move to opposite ends of the cell to define poles of mitosis.
• Pro-metaphase is where the mitotic spindle forms through the polymerization of tubilant proteins. The nuclear membrane has completely disappeared
• Metaphase is where chromosomes line up at the metaphase plate, allowing microtubules to attach to kinetochores in chromosomes. They are still held in place due to cohesin loops that hold them in place.

  
• Anaphase is when the cohesin loops are cut to cause the kinetochore microtubules to shorten (as they are consumed by the centrosome moved by motor proteins) and pull sister chromatids to opposite poles. Non-kinetochore microtubules elongate to stretch cell.

  
• In Telophase, microtubules are depolymerized and spindle fibers disappear. Chromosomes relax and unwind into chromatids, as nuclear membranes start to form around each chromosome.

  
• Lastly, Cytokinesis is the phase in which the vesicles of each chromosome overlaps and fuses into a nucleus that encases all the DNA in it. A cleavage furrow forms to pinch through the divide and spilt the mother cell into two daughter cells.

  
• Mitotic index = (# cells in mitosis)/(# of all cells)
• The mitotic index can help us detect cancer as it lets us know when growth is abnormal
• Ring of contractile actin and myosin proteins pinch the cell and facilitates cytokinesis in animal cells
• Vesicles assembles sections of the membrane and cell wall, facilitating cyokinesis in plant cells
• Cytokinesis is not always equal as not always does each cell have the same number of organelles which causes cell death. Oogenesis in humans (egg production) and budding in yeast are examples of this unequal splitting but in cases where they have all the necessary organelles but lack the same volume, making them less favorable
• Histones are proteins that DNA wraps around to be condensed (nucleosomes- "beads on a string"). Histone proteins have "tails" which other groups can add onto and modify to express and determine which genes are expressed or silenced (regulatory role). When the tails interact, they form loops, further condensing DNA.