Meiosis Cell Division
Definition of Meiosis: Meiosis is a complex cell division process in which the diploid number of chromosome of the mother cell is reduced to haploid number of chromosomes in the four daughter cell.
Importance for Meiosis: meiotic cell division is associated with the conservation of the chromosome number of the species. It influences the adaptation and evolution of organisms. Variations are observed in new offspring.
Occurrence: It is observed in the eukaryotic diploid germ cells of the sex organs of the plants and animals. The meiocyte of the plant cells are called sporocytes (micro sporocytes in male plant and megasporocytes in female plant). In animals, meiocyte of gonads are called monocytes, which may be spermatocytes in male and pictures in female.
Types of meiotic cell division: Meiotic cell division can be classifieds into three types on the basis of the type of cell, where it is occured-
1. Zygotic or initial meiosis - This the process of meiosis which takes place immediately after the formation of zygote by Sunday. It is observed in lower plants like diatom, certain fungi and sporozoa.
2. Gametic or terminal meiosis - Process of meiosis occur at the time of gamete formation (spermatogenesis and oogenesis). It is observed in lower plants and higher animals.
3. Sporic or intermediary meiosis - This type of meiosis occurs at the process formation in lower plants as well as flowering plants by microsporogenesis.
Factors affecting meiosis- Factors that affect meiosis are follows-
1. Completion of vegetative growth.
2. Maturation of sex organs.
3. Due to the disbalance of nucleic acids and certain hormones.
4. When there is increase in the amount of DNA and RNA.
Process of Meiosis - The process of meiosis cell division is made up of two stages. They are – 1st meiotic cell division and 2nd meiotic cell division.
First meiotic cell division is known as heterotypic division which is associated with the reduction of chromosome numberand second meiotic division is also called mitosis due to equal division as it gives birth to the four haploid number of chromosome from two haploid parent cell. It is also called homotypic division or equational division.
First meiotic division is consists of prophase I, prometaphase I, metaphase I, anaphase I, telophase I. This subphages are associated together to called karyokinesis. After karyokinesis or nucleus division, cytoplasm division or cytokinesis takes place.
Prophase I is also made up of leptotene, zygotene,pachytene, diplotene, diakinesis sub stages.
Second meiotic division is consists of prophase ,metaphase, anaphase, telophase.
Questions and Answers on Meiosis Cell Division:
1. What do you mean by cytokinesis?
Cleavage and division of cytoplasm is called cytokinesis.
2. What do you mean by meiocyte?
Any cell which is under going meiotic cell division is called meiocyte.
3. Why there is combination of characteristics observed in the meiosis?
Combination of characteristics are observed due to the crossing over which takes place during pachytene sub stage of first meiotic cell division.
4. What is synaptic knot?
In case of plant cell ,the chromosomes clump at one side of the nucleus is called synthesis or synaptic knot.
You might like these
Explain about Cell Cycle | Definition | Different Phases|Cell Division
Cell cycle is the entire sequence of events happening from the end of one nuclear division to the beginning of the next. In 1953 Howard and Pele denoted four phases of cell cycle G1, S, G2 and M phases.
Phases of Cell Cycle | Definition | Interphase | M Phase | Mitosis
Definition of cell cycle- Cell cycle is a series of cyclical changes by which a cell passes during its growth and division. Generation time- The time interval between the two successive divisions are called generation time. Different division of cell cycle- Cell cycle
Explain about Interphase | Definition| Post mitotic Gap Phase |S-Phase
Interphase is a stage between two mitotic cycles in an eukaryotic cell, during which various physical and chemical changes for the preparation of cell division takes place.
Explain about M Phase | Definition and Types of Mitosis Process
The term mitosis was first coined by the scientist Flemming in 1882. The details were worked out by Strasburger in 1875 and Flemming in 1879. In 1960 Cocktail and Mac Canley explained the biochemical aspect of the process and initially the two process mitosis
Significance of Mitosis Cell Division | Hereditary Conservation
Places for mitosis- cell are divided by the process of mitosis in bacteria, protozoa, dinoflagellate, mammals. Beside the mammalian cell, other cell division of mitosis is quite different, as the nuclear membrane remain intact. But in mammalian cell the nuclear membrane
Significance of Meiosis Cell Division | Evolution | Adaptation | Cell
Meiosis cell division is happened in two stage- first stage is called meiotic first division and second is called meiotic second division. First stage of division is also called reduction division and second part is same as mitosis division.
Meiosis I |Telophase I | Metaphases I | Definition of Leptotene
First meiotic division- Process of meiosis is start with the interphase like that of mitosis and DNA duplication takes place at the premeiotic “S” phase. The first meiotic division consists of prophase 1, pro metaphase1, metaphase 1, anaphase 1, telophase 1.
Meiosis II | Location | Interkinesis II | Prophase II | Metaphase II
Meiosis is a complex type of cell division where a number of chromosome of the mother cell is reduced to the haploid number of chromosome in daughter cell.
From Meiosis Cell Division to HOME PAGE
New! Comments
Have your say about what you just read! Leave me a comment in the box below.