11.   X-rays can be extremely damaging to living cells.

12.   Protein molecules compose all the complex working parts of living cells.

13.   In minute organisms, such as the Protozoa, the movement of material is diffusion, in association with the protoplasmic streaming which normally occurs within living cells.

14.   The process of energy production in living cells is an example.

15.   The hydroxyl radical can attack and damage almost every molecule found in living cells, including proteins, carbohydrates, lipids, and DNA.

16.   And no one has been able to get unnatural DNA to function in living cells, although progress has been made in test tubes.

17.   And the DNA molecules, in turn, would later have surrounded themselves with membranes to become the first living cells, according to the widely held theory.

18.   Biologists cannot yet synthesize a living cell from the appropriate chemicals.

19.   After several days he found that many organic chemicals typical of living cells, including amino acids, the building blocks of proteins, had formed within the concoction.

20.   But although such an arrangement of molecules would certainly duplicate some attributes of life, Rebek foresees large obstacles in deciphering the process by which nature created living cells.

a. + cell >>共 936
human 5.69%
terrorist 3.63%
immune 2.97%
new 2.79%
holding 2.26%
normal 2.16%
epithelial 2.06%
living 2.02%
cancerous 1.98%
embryonic 1.86%
living + n. >>共 685
condition 15.02%
quarter 5.67%
thing 5.25%
expense 3.42%
organism 3.05%
creature 2.60%
cell 2.37%
area 2.30%
arrangement 2.16%
memory 1.97%
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