The cell. Кулагина Ж.Д. - 25 стр.

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      Ex. 19. Arrange the sentences of the ex. 18 so that they can be used as a
plan for text B. Give the content of the text in detail using this plan.


     Ex. 20. Translate into Russian the sentences below, paying attention to the
meaning of the words "this" and "that".

1. Mitotic activity depends on the nature of the tissue and on its physiological
conditions. This is particularly intensive during growth and regeneration. 2.
Through the openings in the membrane the cytoplasm of the cell communicates
with that of neighbouring cells. 3. The cellular wall is the main and principal
feature distinguishing the cells of plants from those of animals. 4. The daughter
cells grow to the size approximately that of the parent cell. 5. The blood cells of
a frog are larger then those of an elephant. 6. Cell components seen under a light
microscope can be compared with those shown under the electron microscope.
7. The teacher told us about some general Lab Safety Rules so that we should
be careful working in the laboratory.

      Ex. 21. Listen to the recording of text C and say what types of growth are
mentioned in it and what peculiarities each of them has.

                                         Text C

       There is usually a limit to the size which any type of cell in an organism
may normally attain. Once this cell size is reached, further growth is impossible
unless the cell divides. After this has occurred the daughter cells may grow to a
size approximately that of a parent cell. In general, large plants and large
animals have large numbers of cells, rather than large cells. However, there is no
definite general relationship between the size of an organism and the size of its
cells; the blood cells of a frog, for example, are larger than the blood cells of an
elephant or a man.
       The growth of a cell involves more than mere increase in size. While it is
growing it continues its other vital activities and maintains the organization
making these activities possible. Although the proportion of the different parts
may change each continues to carry on its functions or functions harmoniously
and in coordination with other parts. The new materials which are added are
distributed in the living protoplasm and become a part of its finely organized
structure. This kind of growth is called growth by intussusception which
distinguishes it from increase in size by the mere addition of material to the
outside. This type of growth is known as growth by accretion.

                                      Unit V
                                      Step 1