Mitosis

Question

Hi, we are currently learning about the stages of Mitosis in my biology class, but I am struggling to understand it. Would you mind explaining the basics steps? Thanks.

mark_liptak · Accepted Answer

Good question.  It can be helpful when trying to understand difficult topics to compare and contrast them to other related ones.    Meiosis differs from Mitosis here in that Meiosis's only purpose in the human body is to produce sex cells (gametes), also known as sperm or egg cells.  Through the process of Meiosis, diploid cells (cells with two sets of chromosomes) are divided into haploid cells ( cells with a single set of chromosomes).  In humans these haploid cells are the sperm and egg cells that eventually join in fertilization to form a complete diploid set or new genome for an offspring.    Let me know if that helps, and remember making a simple list to compare and contrast various biological processes can be very useful in differentiating and understanding them.

mark_liptak · Answer

Hi,  In the most simplistic terms, Mitosis is a type of cell division used to produce more cells that are genetically identical to themselves.  In the context of the cell cycle, Mitosis is the part of the division process in which the DNA of the cell's nucleus is split into two equal sets of chromosomes. For example, in order for a small bear cub to continue to grow bigger and more complex, it must make new cells within its body and throughout its life to replace old or worn-out cells with new ones.   Mitosis consists of four basic phase: Prophase, Metaphase, Anaphase, and Telophase (*some textbooks may list five; breaking Prophase into an early phase and a late phase).  Prophase is the first step, which involves the packing and condensation of chromatin into chromosomes.  The centriole pairs also separate, moving to opposite poles of the cell and the spindle forms; signifying the cell's preparation to divide.  In Metaphase, the chromosomes essentially align along a central axis and the centrioles send out specialize tubes that connect to the chromosomes (*actually the centromere, the center connecting both strands of a chromosome).  Next, we move to Anaphase, where the sister chromatids (making up each chromosome) separate at the centromere and are pulled to the opposite poles of the cell.  They are not their own distinct chromosomes!  Lastly, in Telophase, new nuclear membranes form, splitting the cell into two separate cells, each with half of the original DNA (chromosomes).  This phase can essentially be looked at as the reverse of Prophase.    That's the bear bones (*yes, pun intended) of how Mitosis works to help divide and produce new cells.  Please let me know if you need any more clarifications and/or want me to go more in-depth on each individual phase.