Fill in the gaps with the following words. redox / concealed / unresolved / overlapping / enables / oscillator / values / confusion

redox / concealed / unresolved / overlapping / enables / oscillator / values / confusion

1. The greater relative surface area of small cells ______________ more rapid communication between the cell interior and the environment.

2. To avoid ______________ in studying files of cells, it is necessary to clearly identify the starting point of each file of cells.

3. The suprachiasmatic nucleus is a selfsustaining ______________, which means it undergoes spontaneous, cyclical changes in activity.

4. Energy is transferred from one molecule to another via ______________ reactions.

5. Whether the early bubbles that gave rise to cells were lipid or protein remains an ______________ argument.

6. The guiderails are constructed of chainlike protein molecules called microtubules, assembled into ______________ arrays.

7. In effect, selection is operating to prevent change away from this middle range of ______________.

8. ______________ under a thin layer of scales, the eye has a lens and retina and is connected by nerves to the brain.

Translate into Russian

1. Nucleic acid molecules are long-chain polymers (polynucleotides) composed of monomeric units called nucleotides which are themselves complex molecules, each consisting of three components: a nitrogen base, a sugar, and a phosphoric acid radical.

2. The tobacco mosaic virus contains about 6 per cent ribonucleic acid (RNA), the rest being protein.

3. Two levels of analysis were necessary in these experiments, one dealing with the chemistry of the material, and the other with its biological role.

4. Using what is called fluctuation analysis, they took advantage of the fact that bacteria multiply by dividing in two, one cell thereby forming a clone that may consist of billions.

5. Let us consider a number of different clones, each originating from a similar cell.

6. In the genetic studies of all organisms, it is found that some factor pairs recombine freely whereas others undergo restricted recombination yielding recombinants in frequencies varying from 0.0 to 0.5, the actual value being characteristic of the allelic pairs.

7. Very detailed observations of chromosome morphology are possible with the remarkable many-stranded chromosomes found in some insect larvae, the best known being the salivary gland chromosomes of Drosophila larvae.

8. The salivary gland chromosomes are polytene, each consisting of a parallel array of 1024 strands with each strand corresponding to one chromosome of the adult cell.

9. Each chromosome of meiotic prophase consists of four chromatids, two being the daughter chromatids of each parental homologue.

10. The resultant halves migrate to opposite poles, each carrying one chromatid, which can now be called a chromosome.

11. Essentially the DNA molecule consists of two chains, each incorporating a sequence of purine and pyrimidine bases.

12. «Hybrid» molecules had been formed, exactly one half of each consisting of material from the old, heavy DNA, and one half of new unlabelled material derived from precursors in the medium.

13. The extracted DNA formed two separate layers, each containing half of the total DNA, one corresponding to «hybrid» DNA, and the other to unlabelled DNA.

14. Bу 1950 it was thus known that the sickling disorder was inherited and was characterized by the production of a slightly different hemoglobin in the red cells, the difference being in the protein part of the molecule.

15. The shape of this molecule is that of a triangle, with the hydrogens each sharing two electrons.

16. Sanger discovered three such bonds in the insulin molecule, one connecting two portions of the same peptide and the other two holding the two peptides of the insulin molecule together.

17. Wang carried out an interesting study on catalase, the enzyme catalyzing the decomposition of hydrogen peroxide into oxygen and water.

18. The driving energy for the scheme is therefore ATP, its terminal phosphate supplying the force necessary for cycling the mobile carriers from one side of the membrane to the other.

19. This figure should be complexed by three more sets of numbers, one set giving information about what is called the «free valence» of the single atoms of the ring, the other describing the «bond-order» of the links, and the third giving the «localization energies».

20. All oxidations of organic molecules although they are bivalent proceed in two successive univalent steps, the intermediate state being a free radical.

21. To lift an electron in DPN from the ground state into the first excited level of the same molecule, we would need a quantum, of about 85 К cal., these substances having their absorption in the U. V.

22. In organic substances electrons occupy orbitals in pairs and in oxidoreduction an electron pair is transferred from one molecule to the other, two new closed shell molecules being formed.

UNIT 10 Photosynthesis as Process of Energy Transfer and Energy Transformation

Molecular processes of energy transformation take place in many metabolic systems. Of special interest, however, are the primary reactions in which the quantum energy of sunlight is transformed into the energy of chemical bonds. This is the case in photosynthesis, as well as in photoreception. Photosynthesis is the first step of energy gain in the biosphere. Photoreception on the other hand, is a process of signal transduction.

About 0.05% of the total 10²² kj energy which reaches the earth every year from the sun is assimilated by photosynthesis. This is the general energetic pool for all living processes of the earth. The efficiency of photosynthesis is very high, compared with our recent technical equipment. A large amount of the energy of sunlight, absorbed by the photosynthetic reaction centers of the green plants is transformed by the primary process of photosynthesis. During subsequent metabolic processes of energy transfer, however, an additional loss of energy occurs. The total efficiency of the process of photosynthesis, in fact, is assumed to be about 5%.

In eucaryotic plants the process of photosynthesis occurs in the chloroplasts, especially in the thylakoids located there. Thylakoids are flat vesicles with a diameter of about 500 nm, stacking together to form so-called grana. About 10³ thylakoids are located in one chloroplast. Every thylakoid contains about 10⁶ pigment molecules. A precondition for the efficiency of energy transfer in the process of photosynthesis is the high degree of supramolecular organization.

In general, photosynthesis can be considered as a reaction during which water is split, driven by the energy of photons, producing O₂, and transferring hydrogen to the redox system NADPH/NADP⁺, the nicotinamid-adenin-dinucleotid phosphate. Simultaneously, a proton gradient across the thylakoid membrane is generated. Within a separate process, this leads to the synthesis of ATP. Subsequently, an ATP-consuming synthesis of carbohydrates occurs. This process is usually called the dark reaction of photosynthesis occurring in the stroma of chloroplasts. In general, photosynthesis can be considered as the reversal of respiration.

Define the following words using a dictionary

Photoreception, gain (n), primary,precondition, a stroma, reversal

Complete the sentences

1. Of special interest, however, are…
2. The efficiency of photosynthesis is very high, compared with…
3. A large amount of the energy of sunlight,…
4. During subsequent metabolic processes of energy transfer,…
5. In eucaryotic plants the process of photosynthesis…
6. A precondition for the efficiency of energy transfer…
7. In general, photosynthesis can be considered as…