Biology: THEORY OF REPRODUCTIVE CELLS

The state of the cell to division with a variety of purposes
A. Multiplication of cells resulting in growth
2. New cell formation differs from its parent
3. Formation of new cells, certainly younger and similar to previous ones.
4. Network formation
5. Cell regeneration
6. Establishment of new individuals. etc.
Cell called a stem cell divides, and the results of division are called daughter cells.
Stem cells move copies of genetic information (DNA) into daughter cells.
If it is a direct genetic transformation (amitosis), and if through the stages (mitosis / meiosis)
To convey the genetic information of the stem cell must double its
its genetic information (DNA) through replication (duplication) before carrying out cell division or reproduction, replication occurred at the interphase (resting cells do not divide) exactly on the synthesis phase (S)
Cytology FORMS
Based on the presence or absence of cleavage stages, the reproductive cells be distinguished by:
A. Direct cleavage (Amitosis / binary fission)
Cleavage takes place spontaneously, without the stage of cell division. Dilakulan by prokaryotic organisms such as bacteria and archaebacteria and unicellular organisms (unicelluler) a clear division does not occur in multicelluler organisms (multicellular organisms)
2. Indirect division (mitosis and meiosis)
Cell division occurs through the cleavage stages. Performed by eukaryotic organisms such as animal cells, plant cells and human cells, which of course they all have more than one cell (multicelluler)
Mitotic
Division that aims to
A. replace or repair tissue that is damaged or worn,
2. growth (cell multiplication so that both the quantity and quality, increase).
3. The network formed as a product of this division the chromosomes / parent properties similar to anakannya nature, meaning that for both cells form a network of new and old alike.
Mitotic division of a character
A. take place in somatic cells
2. produce 2 pieces of identical daughter cells with the parent.
3. perform all cleavage
4. advance of division one with the second phase interspersed with interphase (nondividing resting)
5. Cell puppies have the same number of chromosomes as the parent of its
the parent has the ability to divide again, this does not occur in puppies results miosis
6. the organism can occur at younger ages, adults, or old age, which in miosis cleavage can only occur in adulthood are not in organisms that young age
7. IPMAT interphase stage again once the new PMAT
The following description
Mitotic stages are:
Interphase
Is the resting phase of cell division. But by no means the cells do not indulge this stage it is tahapn the most active and important to prepare and cleavage.
This phase requires the longest time compared with the phase of the cell division phase (mitotic phase).
Divided into three phases, namely:
A. G1 phase (growth 1/pertumbuhan 1)
Is the most active phase lasted for 9 hours. In this phase the cells entered the growth and development. In this phase, increased cell size and volume.
2. S phase (Synthesis)
Is the phase of DNA synthesis or chromosome duplication, with a time of 10 hours
3. G2 phase (Growth 2/Pertumbuhan 2)
Is the phase in which the process of protein synthesis. In this phase of cell division was ready to hold

Once again that is not preceded by a phase Mitosis Interphase Prophase phase but, as a preparation for mitosis interphase, is the resting phase cells do not divide.
Mitosis phase of the cell while it is doing division / reproduction.OK
A. Phase Prophase
An early stage of cell division in mitosis and meiosis, which is characterized by:
A. Chromatin to form chromosomes shorten and thicken, then doubled to form kromatida chromosome.
2. nuclear membrane and nucleolus (core child) disappear
3. centrioles separate self toward the opposite pole.
4. Spindle threads coming out of each different set of centrioles at the poles themselves holding each chromatid was irregular.
5. Abandoned shortly push the chromatids becomes very regularly toward the equator area.
2. Metaphase
This stage is characterized by:
A. chromatids / chromosomes arrange themselves on the equator the field / area of the cleavage face to face.
2. Each centromere has two kinetochore, each linked by a thread spindle
3. Of course it's the opposite chromosome carrying the same genetic code because it is his vision to form two cells together.
3. Anaphase
This stage is characterized by:
A. Both chromatids apart toward opposite poles
2. state of the cells become elongated, curved membrane, in late anaphase
3. This phase separation occurs naturally sets of chromosomes / reduction of chromosome tetrad when dealing in the phases separate into each metaphase 2n (diploid)
4. Telophase
This stage is characterized by:
A. Chromosomes / chromatids have reached opposite poles
2. form bulkhead dividers so that the cells appear to form two cells with one nucleus each
2. Formed nuclear membrane and nucleolus begin to wrap the chromosomes appear
3. Thinned and elongated chromosomes into chromatin and finally disappeared
4. Cytokinesis occurs (curved plasma membrane) that preceded by Karyokinesis (core so 2) and finally seen the cell divides into 2
so the conclusion
Mitosis in these guidelines is
A. memorize the cell will divide (G2), which continues to Prophase (Start)
2. Also memorize the finished dividing cells (G1) in late telophase to interphase again later (Finish)
Of course knowing the start and operation between the start and finishnya finisnya can be analyzed more mudah.Karena already know the ending
Start (the cell will divide / early prophase late G2)
A. large cell size
2. No change in muddy as the core items of chromatin-chromatin-thread-chromatid chromosomes
3. centrosome eventually split into two centrioles kekutub
4. the core is missing children as well as the membrane core
5. reduced activities of daily metabolism to reproduction
Kerbalikannya to Finish (cells divide / late telophase / early interphase
have the opposite character traits from the start
for example
A. chromosome - so thin elongated form of chromatin - point - gone
2. membrane and the core of children who no longer produce RNA for wanting to make the protein in preparation for splitting later.
for details, see the picture of this Mitosis

Meiosis (reduction division)
This cleavage occurs in sex cells but not in the sex glands such as the testes or ovaries in which the division to form sex cells (n) from the cell body (2n / diploid), the cells that form the body of the cell body but not indiscriminate sex stem cells or sperm stem / stem ovum which has the Latin name of spermatogonia / oogonium both parents continue to be formed but it is clear that in mitosis (2n-2n)
Aimed mitosis
A. to form sex cells.
2. form a reduction in chromosome number (reduction)
3. reduction aims to form a zygote results from perteuan two sex cells are always the same as the existing individual / individuals previously
4. to achieve meiotic division takes place in two stages, namely meiosis 1 and meiosis 2 directly without doubling again because there should be a reduction of chromosome
Meiotic stages are as follows:
Because of the body's cells that can form the sex cells begins with the phase in which cells grow and develop. Is to hold a preparatory stage of cell division. In this phase of DNA replication events from one copy to two copies. End of phase produced two copies of DNA and chromosomes turned into ready
b. Prophase I
Is the longest stage of prophase I stage of meiosis 1 than the other
Divided into: LeZy PaDiDi
A. Leptoten
This phase is characterized by thickened chromatin threads shorten turn into chromosomes.
2. Zigoten
This phase is characterized by homologous chromosome pairs close to each other and form synapses or bivalent (Searchng homologous chromosomes)
3. Pachytene
In this phase there duplication or replication of the chromosome, a chromatid with two centromeres are still together or berlekatan and not divide, so-called tetrad. (2n - 4n)
4. Diploten
In this phase can occur between the chromosome arm chiasma.Kiasma is a moving scene of the possibility of crossing over occurs silang.sehngga yes at this stage
5. Diakinesis
This phase is characterized by the emergence of spindle thread that comes out between the two centrioles, which has been at opposite poles. In this phase the nucleolus and nucleus membrane disappears, and tetrad budang began to move toward the equator.
For more details see Figure

APPLICATIONS In meiosis cell division is the formation of sex cells, the following we present how the real process of meiosis in the event Gametogenesis
gametogenesis
Gametogenesis is the process of formation of gamete cells,which occurs in meiosis at the breeding tool. Gametogenesisoccurs in adult organisms. Gametogenesis in animals andhumans occurs in the testes and ovaries.
1, Spermatogenesis
Is the process of sperm formation occurs in the testes
Stages of spermatogenesis are:

The miosis seen in Figure 1 (left) there is a reduction (reduction) of chromosomes 2n - n
Spermatogonia (2n) - primary spermatocytes (2n) - so the twosecondary spermatocytes (n)
whereas in meiosis to 2 (picture right) actually occurred mitosisbecause of n - n
2 Spermatocyt divide mitosis II - 4 spermatids (n) - whicheventually came to form spermatozoid tail (n), amounting to fourdaughter cells of all living sperm
obviously wanted to see more pictures

To be complete we also present the process of oogenesis is principally the same as spermatogenesis anakanovum cell only one that lives only 3 polosit / cell polar / polar body is dead because no core
Oognesis process