The main questions that embryology has always tried to answer are the following: How can the fertilized egg, which has received a nucleus from the mother and another from the father, give rise to all the organs present in the adult? How is it possible, at a given time of development and in a special region of the embryo, that a limited number of cells can differentiate into muscles or red blood cells? It is the purpose of molecular embryology to answer such questions in terms of the properties of macromolecules. Although we are still very far from obtaining a complete answer, spectacular progress in molecular biology has allowed us to state the same problems in simpler terms. For instance, the word "nucleus" can be replaced by "a set of genes" or still better, by "deoxyribonucleic acid (DNA)"; the fertilized egg has, in fact, received equal amounts of paternal and maternal DNA and this constitu ent is really the most important part of the nucleus, since it contains, in its own molecules, all the program for development into an adult. As for the second question, biochemistry tells us that muscle cells would fail to contract and would not display their characteristic structure under the microscope if they did not contain considerable amounts of specific proteins: the so-called "contractile" proteins, actin and myosin.
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paperback. Condizione: Good. Heidelberg Science Library Volume 19. The previous owner's name is on the half-title page in pen. Good paperback, bumped/creased with shelfwear; may have previous owner's name inside. Standard-sized. Codice articolo mon0000228804
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