Student's Study Guide for LessonThree Mitosis by Dr Jamie Love 2002 - 2010

Mitosis is specifically designed to distribute _____ and ____ amounts of genetic material so the daughter cells are genetically _________ to each other (and the mother nucleus that they came from) - ______.

Mitosis increases the number of ______ and that usually leads to an increase in cell numbers too.

Species that reproduce this way are clones and this method of reproduction is called _______ reproduction. Clones are produced without sex and without _______. Plants are "masters" at cloning and that is why asexual reproduction is often called __________ reproduction or vegetative ___________.

Mitosis is a flow of events but we have divided it into four obvious stages

1. P_______
2. M________
3. A_______
4. T________

During prophase the chromatin condenses into ___________.
This is the distinguishing characteristic of prophase - _______, ___________ chromosomes (a "ball of _____"). Prophase is a rather long process and is often divided into _____ and ____ prophase.

During prophase, as the chromosomes continue to condense, the centrosomes move to opposite "_____" dragging their spindles along.

Eventually the cell enters late prophase and, because the next phase will be metaphase, late prophase is often call ____________. During prometaphase two very important events occur. The nuclear envelope ______ ____. The microtubules (fibers) attach to ___________.

Late in prophase two special structures grows inside of the centromere region of every chromosome - one on each _________. These structures are called ____________. ("Kinetos" is Greek for "movement".) The kinetochore attaches to the __________ that make up the spindles from the centrosomes. Once attached, the spindles run from _________ (one on each chromatid) to the _________ (one on each side), so each chromosome is held between the two centrosomes via the ________.

A series of tugging from both kinetochores on their spindles cause the chromosomes to move back and forth until this "tug-of-war" ends in a "draw" - the chromosome is then positioned ______ between the centrosomes. ___ the chromosomes behave this way.

Therefore, all the chromosomes come to line up midway between the two ___________. When all the chromosomes' centromeres are lying on a plane _____________ to a line connecting the two centrosomes, the cell has entered the part of mitosis called _________. The plane upon which the centromeres are arranged is called the _________ _____.

Metaphase lasts for about an hour and is the ____ time to see chromosomes.

At ________ the centromere of each chromosome breaks down the middle (!) and the two sister __________ move to opposite centrosomes. It is at anaphase that "true" _______ division occurs.

As each kinetochore drags its chromatid along, the arms of the chromatid are swept back and they seem to form a __-shaped structure. All the chromosomes are able to coordinate the breaking of their centromeres quite well and the speed at which the chromatids move is impressive so anaphase is a sight to see! (In a ______ cell, of course.)

The moment the chromosome's centromere splits (during ________) each kinetochore acts as the center for the creation of a new centromere. Each chromatid is "puckered" inward at the kinetochore during anaphase and that is the new __________. The trick to counting chromosomes and differentiating them from chromatids is to keep track of the __________. A chromosome has a single centromere and each chromosome has two kinetochores at the centromere - one on each _________.

By definition a chromosome has a centromere - it's a __ to __ correspondence. During anaphase, each chromosome becomes two separate chromosomes at that moment of chromatid _________ and we now have two chromosomes from each chromosome! During anaphase and until cytokinesis occurs, the cell has _____ as many chromosomes as "normal".

Once the newly created chromosomes reach their poles, anaphase is ____ and we enter the next and last phase of mitosis - _________.
"Telo" is Greek for "end.

Telophase is the point in mitosis when the new ______ are formed. A nuclear membrane forms around both bundles of chromosomes at each ____. This creates two nuclei. Also, the chromosomes begin to ______ (decondense) until eventually they are nothing more than a dim coloring of chromatin with a few nucleoli (clumps of chromatin). Each nucleus takes on the appearance of an interphase nucleus and once that is done the cell has completed telophase and _______.

Telophase produced the identical nuclei that we now call ________ nuclei because they will be the nuclei of the daughter cells produced from the upcoming cytokinesis.

Not only are the daughter nuclei identical to each other but they are also identical to the ______ nucleus from which they came. The daughter nuclei are clones of each other and clones of their mother nucleus. Also, notice that a (mother) cell must have ___ centrosomes in order to orchestra mitosis, but both (daughter) cells produced (after cytokinesis) have only __ centrosome each (until they enter late __ and the whole cycle starts again).