What in the world is Meiosis?!

Well to start with meiosis is a type of cell division in which the eggs and sperm are produced.  Meiosis includes a lowering of the genetic material.  Meiosis is made up of two successive nuclear divisions with only one round of replicating the DNA.  The four stages of Meiosis are interphase, prophase, metaphase, anaphase, and telophase, but it happens twice!  Here is the stages in a little more detail!
Interphase- This is before meiosis begins and genetic material can be doubled.
The first division of meiosis starts with prophase 1, which is when duplicated chromatin condenses.  Every chromosome is made up of two, closely related to sister chromatids.  Crossing-over is possible at the end of this stage.
Metaphase 1 is when homologous chromosomes line up at the equatorial plate.
Anaphase 1 is the time at which the homologous pairs separate with sister chromatids remaining attached.
In Telophase 1 two daughter cells are made with each daughter that includes only one chromosome of the homologous pair.

The second division of meiosis is when the gametes form.  It starts with Prophase 2; this is where DNA does not get replicated.  In Metaphase 2, chromosomes line up at the equatorial plate.  During Anaphase 2 centromeres divide and the sister chromatids move separately to each pole.  At the Telophase 2 phase cell division is finished.  Four haploid daughter cells are collected.

One parent cell produces four daughter cells.  There is only half the number of chromosomes in the daughter cell that are found in the original parent cell.  If crossing over occurs, they are genetically different.
Meiosis is different from mitosis because there are two cell divisions in meiosis which ends in cells with a haploid number of chromosomes.  Overall meiosis, is a very drawn out process and can be complicated to most people, but once you get the just of it, it makes a lot MORE sense!

All of the Meiosis Steps!

This is the site where I got all of my info from!!! :)
http://www.accessexcellence.org/RC/VL/GG/meiosis.php

My Self-Reflection and Goals! :)

For this semester I would like to learn more about genetics and the forming of a baby!  Since this is the last of my junior year I would love to pass this semester with a high B or A :) I've actually learned a lot in college biology even though the first quarter was mainly all about facebook because i just couldn't concentrate whatsoever!  But thankfully in the third quarter I'm doing a little better.  However I need to get my rear in gear and catch back up on all of my posts darn it!  :) Well that's all I have to say for now! :)

Mitosis! :)

In the Mitosis process, there are six stages starting with interphase.  Interphase is where the chromatin is undifferentiated in the heavily-stained nucleus.  Before a cell begins mitosis, it has to undergo a synthesis phase where every chromosome is duplicated and is made up of two sister chromatids joined by a specific DNA sequence known as a centromere.

The first initial phase of mitosis is called prophase.  The nuclear chromatin starts to be organized and forms into thick strands that eventually become chromosomes.  During this stage, the cytoskeleton begins to break down and the main piece of the mitotic apparatus, the mitotic spindle begins to shape outside the nucleus at opposite ends of the cell.  

early prophase

The next phase is metaphase, or the middle of all the stages.  Metaphase is when the chromosomes, attached to the "kinetochore microtubules," begin to align in one plane halfway between the spindle poles.  The microtubules apply a pull on the chromosomes and the entire spindle-chromosome complex is ready for the next phase.  In metaphase, the kinetochore and polar microtubules are clearly seen and radiate out the ends of the cell which leave the chromosomes in the middle of the complex.

metaphase

After metaphase, the cell begins anaphase.  After the metaphase chromosomes are aligned at the metaphase plate, the two halves of chromosomes are pulled apart by the spindle apparatus and move to the opposite spindle poles.  As the chromosomes are pulled toward the poles the kinetochore microtubules shrink, while the polar microtubules lengthen to assist in seperating.  Anaphase is the fastest stage in mitosis.  

Anaphase

The last stage of Mitosis is called Telophase.  In this stage, the daughter chromosomes arrive at the spindle poles and are finally redistributed into chromatin.  Cytokinesis also continues through telophase.  After the chromosomes are completely separated and their extrusion to the spindle poles, the nuclear membrane begins to reform around each group of chromosomes at the opposite ends of the cell.

Telophase

Overall Mitosis is a fairly long process and at the end it results into two daughter cells.  The process then starts all over again.
http://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html