Nota Terkini

Thursday, February 11, 2010

[Biology Form 4] The Haploid Cells

Another type of cell division is known as meiosis. Meiosis involves the division of a cell into four daughter cells. It takes place only in reproductive organs (eg: in the testes and ovaries of animals and in the anthers and ovules of plants).

The purpose of meiosis is to produce gametes or reproductive cells so that sexual reproduction in organisms can occur.

Unlike those produced through mitosis, these daughter cells are usually not genetically identical to their parent cells. The chromosomes in each daughter cell are half the number found in the parent cell.

While cell division occurs once during mitosis, cell division occurs twice during meiosis. Meiosis I is followed by Meiosis II.

In Meiosis I, the cell divides into two daughter cells, whose number of chromosomes is halved. In Meiosis II, each of the two daughter cells divides into another two daughter cells, resulting in four haploid daughter cells (with the same halved number of the original chromosomes).

Shown in the following diagram are the basic differences between mitosis and meiosis.


6 comments:

  1. tc, i still confuse abt this division.
    let say, the parent cell is 12. when it undergoes
    meiosis 1 which produced 2 daughter cells, is tht mean tht the chromosomes now is 6 for each daughter???

    and wht happen to the number of chromosomes when
    they complete meiosis 2, 4 daughter cells? 3 for each????? help me. tq

    ReplyDelete
  2. Hi,

    In Meiosis 1, during the prophase 1, the 12 chromosomes will duplicate to form the 24 chromosome. Then, undergoing the several phases, until the last phase (telophase), the cell will form 2 daughter cells, which each daughter cell has 12 chromosomes.

    In Meioisis 2, there is no duplication of chromosomes. The 2 daughter cell divided into 4 daughter cells (2 daughter cells each), which each daughter cells has 6 chromosomes.

    Tq.

    ReplyDelete
  3. ohhh, 6 is for each of the 4 the daughter cells then?
    so 6x4=24 chromosomes??

    ReplyDelete
  4. tq very much tc :)

    ReplyDelete
  5. is the cell(parent cell) before undergoing meiosis halpiod?or diploid

    ReplyDelete