The cell. Кулагина Ж.Д. - 24 стр.

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produced. 5. The younger an organism, the higher is its water content. 6. The
younger the tissue, the more frequently the cells divide. 7. The earlier the stage
of an embryo, the more alike are its cells. 8. Up to a certain point plants grow
rapidly the higher the temperature. 9. The more we learn about the complexities
of the mammalian nervous system, the more apparent it is that animals suffer
significantly even in routine research. 10. Many chemical reactions in an
organism go on more rapidly, the higher the temperature. 11. The lesser the
environments change, the lesser power of adaptation their inhabitants need to
have.

      Ex. 17. Read the text. Collect sentences with the Absolute Participle
Construction.

                                          Text B

       The duration of each phase of mitosis and its frequency are dissimilar for
different cells and vary greatly. The younger the tissue, however, the more
frequently the cells divide.
       Mitotic activity depends on the nature of the tissue and on its
physiological condition. This is particularly intensive during growth and
regeneration, hormones and other system regulators of the organism having a
great effect. In many tissues mitosis is not observed as in the liver. That,
however, does not mean that liver cells cannot divide. If, for instance, a piece is
cut from the liver of a rat, mitosis will occur immediately along the line of the
cut, and the liver will quickly and completely regenerate.
       During division cells are very sensitive to various environmental
influences, temperature being the most important of these agents. The optimal
temperature for human cell-division is 37°C; deviation from that, either above or
below, inhibit mitosis. The dividing cell is likewise sensitive to poisons and to
radiant energy, which is the basis for treatment of malignant tumours by
ionizing radiation.
       It should also be noted that certain highly differentiated cells have lost the
capacity to divide, as for instance, blood cells. After they have existed for a
certain time they disintegrate, and special blood-forming organs produce new
cells to replace them. Nerve cells are formed only during embryonal
development. After birth they grow, but do not divide.

      Ex. 18. Put all possible questions to the following sentences.

   1. Duration of each phase of mitosis is dissimilar for different cells.
   2. Environmental factors influence the dividing cells greatly.
   3. Mitotic activity depends on the nature and physiological conditions of the
      tissue.
   4. Some highly differentiated cells have lost the capacity to divide.