2. 职称英语
  3. It can be inferred from the passage that the morphogenetic determinants present

It can be inferred from the passage that the morphogenetic determinants present

游客2024-01-13  45
问题 It can be inferred from the passage that the morphogenetic determinants present in the early embryo are______ [br] It can be inferred from the passage that which of the following is dependent on the fertilization of an egg?
选项 A、Copying of maternal genes to produce maternal messenger RNA’s
B、Sythesis of proteins called histones
C、Division of a cell into its nucleus and the cytoplasm
D、Determination of the egg cell’s potential for division
E、Generation of all of a cell’s morphogenetic determinants
答案 B
解析 B is the best answer. Lines 45-51 indicate that substances that function as morphogenetic determinants are inactive in the unfertilized egg and that when the egg is fertilized, they “become active and, presumably, govern the behavior of the genes they interact with.” In the fourth paragraph, we learn that these substances exert their control over the fate of the cell by directing “the synthesis of histones.” Because these histones cannot be synthesized until the substances that function as morphogenetic determinants become active, and because these substances do not become active until the egg is fertilized, it can be inferred that the synthesis of the histones is dependent on the fertilization of the egg.
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