Fill in the gaps with the following words and word combinations. atomic nucleus / quantum numbers / potent / orbitals / quiescent

atomic nucleus / quantum numbers / potent / orbitals / quiescent

1. A highly ______________ drug (e.g., morphine, alprazolam, chlorpromazine) evokes a larger response at low concentrations.

2. The most important fact in connection with the study of the phenomena of heat is that a substance settles to a ______________ state in which there is no tendency to further change of any kind when it is left to itself and shielded from all outside disturbing influences.

3. As electrons are added, the ______________ build up the orbitals.

4. The ______________ is the center of an atom.

5. Despite the obvious analogy to planets revolving around a star, electrons cannot be described as solid particles and so atomic ______________ rarely, if ever, resemble a planet's elliptical path.

Translate into Russian

1. One may then ask: Do exchanges among the four strands occur at random as would be expected if the strands wore identical? If so, the expected frequencies of single and twin exchanges after the second replication would be about 10:1.

2. For the analysis of recombination mechanisms, one requires similar observations of chromosome duplication in meiosis, and such experiments are now being carried out. However, the mitotic chromosomes do provide some genetically relevant information.

3. Having surveyed the available knowledge about chromosome organisation we may now return to the central theme of this chapter: possible mechanisms of genetic recombination. The issue was reopened by the results of phage crosses which differed from those observed with higher forms in every respect except one: the linearity of the genetic material.

4. Intragenic recombination at a particular locus is generally too rare an event to be found in an unselected sample of progeny.

5. Replication of DNA seems to be completed before zygotene pairing of homologous chromosomes begins.

6. The correlation of genetic crossing-over with chiasma formation is good and supports the view that reciprocal exchanges do occur.

7. We will first consider whether gene replication is a necessary condition for mutation.

8. There are likely to be at least two mechanisms for spontaneous mutation. The one that is reversible would seem to involve substances like adenine and adenosine which are naturally occurring metabolites.

9. Nonetheless, some unnatural analogues of pyrimidines, when supplied to the cell, are actually incorporated into DNA.

10. These chromosomal aberrations are caused by many agents including some which will not induce mutations. It is not known whether the breaks that cause them are in the backbone of the polynucleotide chain of DNA or whether they involve separation at sites in between the DNA molecules in the chromosome.

11. We may then ask whether some unstable genes may not be the expression of chromosomal rearrangement.

12. It is a matter of historical interest that the Dutch botanist De Vries who was the .first serious student of mutation, actually investigated the result of chromosome rearrangement, rather than what we would now call mutation.

13. That the whole cell is not the target particle is indicated by calculation of the target size.

14. Upon the application of low doses, most cells still have at least one surviving unit, but with larger doses oven these become inactivated. Eventually, the only cells surviving are those with only one unit left.