Fill in the gaps with the following words. representation / resort to / vary / complexity / applications / conform to / inherent / reassembled

representation / resort to / vary / complexity / applications / conform to / inherent / reassembled

1. Many animals exhibit behaviors that ______________ at regular intervals of time.

2. Fats are hydrolyzed into fatty acids and monoglycerides, which are absorbed into the intestinal epithelial cells and ______________ into triglycerides.

3. Other animals and plants simply ______________ the environment in which they find themselves, their bodies adopting the temperature, salinity, and other aspects of their surroundings.

4. New ______________ of a wide variety of molecular methods are providing important insights into the relationships among the protista.

5. The birds ______________ larger, drier seeds, which are harder to crush, only when small seeds become depleted during long periods of dry weather, when plants produce few seeds.

6. As a social species, humans have an unparalleled ______________.

7. Because this size limitation is ______________ in the body design of arthropods, there are no large arthropods—few are larger than your thumb.

8. However, whereas selection is a deterministic process that operates to increase the ______________ of alleles that enhance survival and reproductive success, drift is a random process.

Translate into Russian

1. The question still remains whether proteins also are represented among the hereditary determinants of the cell.

2. One may ask whether the protein moiety may also carry information.

3. We may ask whether the chance of mutation is the same for all cells in a population and constant with time. We may also ask whether the chance that mutation will occur in one mutable unit is independent of mutation in another.

4. Bacterial populations provide convenient systems for the analysis of this process, but the question may be asked whether the results found among them can be generalized.

5. With this analogy in mind, we may ask whether the distance between two genes determines the amount of recombination between them.

6. Mendel's laws hold for all organisms but their consequences appear different according to whether the gametes may be analyzed directly.

7. The extent of lethality among the progeny depends upon whether or not the daughter cell receives a full chromosome complement.

8. Whether there is also exchange occurring between sister chromatids in meiosis is as yet an unresolved question.

UNIT 16 The Water Structure, Effects of Hydration

The physicochemical properties of water are quite different from those of chemically similar compounds, for example H₂Te, H₂Se or H₂S. Astonishing values could be predicted extrapolating the properties of these substances to H₂O. This would predict a melting point of -100 °C and boiling point of -30 °C. Water, therefore, would be a gas under the normal conditions. The same deviations between predicted and actually existing values would be found in relation to other physicochemical properties, such as molar heat of evaporation, heat capacity, surface tension, dielectric constant etc.

Another speciality is the so-called temperature anomaly of water, which is of particular relevance for the generation and preservation of life. Water has its highest density at a temperature of 4 °C. This is the reason why, in contrast to other melting substances, ice floats on the surface, and the temperature of water near the bottom of lakes will not become colder than 4 °C. If water had the same properties as other substances, the cold water would always sink and the lakes would freeze downside up. Life in this lake could not survive the winter.

There are two molecular properties which are responsible for these effects: the dipole moment of water, and the ability of water molecules to build intermolecular hydrogen bonds. Previously we discussed the electronegativity of elements in covalent bonds and found the following sequence: H<C<N<O<F.

Hence, in both H—O-bonds of the water molecule a strong polarization will occur. The common valence electrons in these bonds are strongly attracted by the oxygen atom, which therefore becomes negative in relation to the protons. The positive charges of the two H atoms lead to a repulsion of each other. This increases the angle between them up to a value of 104.5°. The water molecule in all becomes a dipole which is directed towards the bisector of this angle.

This polarization of the H—O-bonds in the water molecule not only has consequences for its electrostatic behavior but is also responsible for its ability to build up hydrogen bonds. They can be built between two water molecules as well as between water and other molecules. This is the reason for the occurrence of the water structure in ice as well as in the fluid water.

Define the following words using a dictionary

A dipole, the charge, relevance, a sequence, a consequence, to extrapolate, the melting point

Complete the sentences

1. This is the reason for…

2. There are two molecular properties which…

3. The positive charges of the two H atoms…

4. The common valence electrons in these bonds…

5. If water had the same properties as other substances,…

6. The same deviations between predicted and actually existing values…