Задания

1. Ответьте на вопросы:

1. What substances are known as carbohydrates? 2. What is sugar responsible for? 3. How is starch built? 4. What is the role of cellulose? 5. What do you know about organic acids? 6. What foods are high in carbohydrates?

2. Кратко расскажите по-английски:

а) об образовании крахмала в растении;

б) о роли сахара в жизни организма.

Работа над текстом № 3 «fats»

Active Vocabulary:

fat, fatty; to take in, intake; to protect, protection, protective; to derive, derivative, derivation; to deplete, depletion; layer; amount; excess; equipment; knowledge; essential; extreme; to include, to perform, to refuse, to call on; to prove; to play a part

Animals, human beings included, take in sugars and starches and store the excess as fat. The ability to make fats from carbohydrates or similar materials seems to be a characteristic of most living matter including plants. But man hasn’t been able to perform this task in the laboratory, even when armed with all the equipment and knowledge in the world. The microscopic walls of plant cells are much better laboratories than our scientists have yet been able to make.

The fatty foods perform some very important function in our animal lives; to do without them can be dangerous. Fats form a protective layer around the nerves, apparently to protect them from shocks. One of the characteristic results of semi-starvation is extreme irritability. It has been suspected that this may be due to the depletion of fat around the nerves.

Fats in the form of their derived compounds – phospholipids – also play an important part in our brain and entire nervous system. Another class of compounds derived from the fats and known as the sterols is also essential for the living organism. So one may say that, in its higher forms, life without fat is impossible.

Even admitting these facts, however, one might argue that they do not prove that a diet should contain any large amount of fat, for we make fat out of the carbohydrates we take in, hence sugars might be all that would be necessary to supply energy. As an argument this is unanswerable – but as an observation of facts it is a hundred per cent wrong. There are fats and fats and the human body is quite unable to meet the fat-manufacturing situation by itself. There are some necessary fats that our bodies refuse to, or cannot, manufacture and we need to call on other animals, such as cows, to help us out. Moreover, without fats in the diet we could not get a sufficient amount of the fat-soluble vitamins A, D and E.

There are two fatty acids, linileic and linolenic, which the body must have and which it cannot manufacture itself. These fatty acids get their names from linseed: oil in which they were first discovered. There are several other fats and fatty acids which are essential and which we do not make in our bodies.

Задания

1. Ответьте на вопросы:

1. What functions do fats perform? 2. What kind of derived conpounds of fats are known? 3. What fatty acids are essential for a human body? 4. Out of what can a human body make fat? 5. Why must we call on animals to help us in fat manufacture?