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how do organisms reproduce ? — Science STD 10 — Question

Gujarat BoardEnglish MediumSTD 10Sciencehow do organisms reproduce ?3 Marks
Question
Explain cell reproduction and tendency for variation inbuilt during cell reproduction.
✓

Answer

  • Cell reproduction means cell division.
  • A parent cell divides into two daughter cells.
  • The creation of a $DNA$ copy is the basic event in the process of reproduction.
  • Cells usually use chemicals to build copies of their $DNA$.
  • This process results in the production of two similar copies of $DNA$ in a reproducing cell.
  • The two copies of the $DNA$ molecule, which are similar with each other, come to two daughter cells.
  • Therefore, $DNA$ copying is always accompanied by the creation of another cellular apparatus.
  • Finally, the $DNA$ copies are seperated into two similar cells, each with its own cellular apparatus.
  • Finally, a cell divides to give rise to two daughter cells.
  • So, only creation of a $DNA$ copy is not sufficient for cell division.
  • Two daughter cells produced by cell division are similar, however they are not likely to be absolutely identical.
  • This is because some variations may arise during the process of copying the $DNA$.
  • As a result, the $DNA$ copies generated will be similar, but may not be identical to the original.
  • Some of these copies of $DNA$ may possess such drastic variation from the original that their survival becomes difficult. Such a new born cell will simply die.
  • On the other hand, some other variations in the $DNA$ copies may be beneficial which can help the cell to survive with slight variation.
  • Thus, the surviving cells are different from each other with slight variation in their features.
  • This is how tendency for variation is inbuilt during cell reproduction.

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