Задания

1. Ответьте на вопросы:

1. Why are vitamins essential in our nutrition? 2. In what form may vitamins be available? 3.Whatisthebestsourceofvitamins?

2. Заполните пропуски и переведите словосочетания на русский язык.

a) exposing; b) exposure; c) to be exposed

1. … vitamins to the sun or ultra-violet light 2. under direct … to air 3. the substance … to sun light

a/destroying b/destroyed c/destruction

1. foods … through oxidation 2. the way of … vitamins 3. the … of vitamins due to long heating

a/having recognized b/recognition c/recognized

1. the … of the significance of vitamins 2. the process generally … as an extremely complex one 3. … the existence of vitamins scientists began to study their properties

a/to be converted b/conversion c/converting

1. a provitamin … into a vitamin 2. … provitamin D into vitamin D under direct exposure to ultra-violet light 3. the necessity of the … of provitamin D into vitamin D within the body

a/affected b/to be affected c/having been affected

1. … by heat the substance changed its properties 2. vitamin A … by light, especially by ultra-violet light 3. the substance … by light in order to destroy it

2. Укажите номера синонимичных пар.

1. convert 2. exceedingly 3. occur 4. expose 5. aid 6. reproduce 7. essential 8. affect 9. constituent 10. easily

1. help 2. readily 3. transform 4. influence 5. happen 6. lay open to 7. vital 8. generate / multiply 9. component 10. extremely

3.Укажите номера антонимичных пар.

1. stimulate 2. presence 3. include 4. strong 5. destroy 6. rapidly 7. rich in 8.stable 9. soluble 10. appreciable

1. deficient in 2. exclude 3. create 4. insoluble 5. inconsiderable 6. changeable 7. weak 8. prevent 9. slowly 10. absence

4.Назовите пропущенные предлоги.

1. most of vitamins are stable ... heat. 2. under the direct exposure ... light. 3. to be converted ... vitamin A. 4. to be rich ... vitamins 5. to oxidize readily ... the presence of acids. 6. to be able to transform carotene ... vitamin A. 7. necessary ... normal clotting of blood. 8. provitamin D is converted ... vitamin within the body. 9. essential... the development and maintenance of bones and teeth. 10.a fat-soluble vitamin is not soluble ... water

1. into 2. in 3. to 4. for

«From the history of vitamins»

1. Прочитайте текст и скажите, какое открытие было сделано польским ученым.

2. Выделите самое главное, говоря о функциях витаминов A, B, C.

In 1911 the young Polish scientist, Casimir Funk, published a book in which he described experiments by means of which he extracted a substance from rice hull¹ which when fed to fowl in very minute quantities cured them of the paralysis of poly-neuritis within a few hours. For this white crystalline substance he gave a name, Vitamine (“Vita” for life, “amine” the name of a certain class of chemical compounds). Though it was soon shown that the life giving material contained no amine the name remained, not only with the researchers but also with the public, and it stayed though it has dropped its “e”. Naturally the first vitamin work was biological. Many organic chemists have attempted to find the exact chemical structures of these extremely complex materials. The principal members of the vitamin groups are A, B, C, D.

For the most part we obtain our vitamins directly from foods but there are amendments to the rules.

Vitamin A can be obtained from fish livers and a variety of other foods of animal origin, or our bodies can manufacture it from carotene found in green leaves and some tubers.

The body can manufacture its own vitamin D from the ergosterol on or near skin, if exposed to sunshine. The functions of the vitamins are very varied, interesting and important.

Vitamin A. It is essential for eyes, nerves growth, reproduction and lactation and the maintenance of bodily vigor at every stage of existence. Life without vitamin A is hardly worth while. Green vegetables, milk, bitter and cod liver oil contain vitamin A.

Vitamin B. The exact amount of vitamin B for optimum human health is not known; but the minimum intake necessary to prevent beriberi or other severe nervous disturbance has been well established.

In common with most of other vitamins vitamin D is necessary for normal growth. There is probably some connection between its growth and appetite-inducing properties.

Vitamin C. The citrus fruits (oranges, lemons, grape-fruits) are sources of vitamin C. Tomatoes, raw cabbage and onions also contain vitamin C. Apples, bananas, carrots and potatoes contain some, but they are important sources only if eaten in large amounts.

If the shortage of vitamin C causes scurvy, the teeth fall out, if the shortage is less, they rot out.

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