The cell

The unit of protoplasmatic organization is the cell. The word “cell” is not a very good choice in this connection, but it has significance in the history of biology. The name was given by Robert Hooke. One of the first scientists having used a newly developed biological tool, the microscope, to the tiny divisions that he saw in these slices of cork. The cork slice through his microscope, appeared to be made up of many small compartments, arranged in rows, and reminded him of the tiers of monks’ cells in English monasteries. He therefore called each compartment a cell and the name has survived, although it does not accurately convey the picture of a living unit. What Hooke actually saw in the nonliving wall which had once surrounded the living protoplasm, was not protoplasm itself. His microscopic studies of some other materials, such as feathers, fish scales, molds, snow crystals and fabrics, brought him closer to the sight of living cells but not close enough to see the living substance.

Observations of the classical microscopists and those of their successors on individual cells as parts of organisms, both plant and animal, led to one of the greatest and for a time most useful of biological generalizations, the cell theory. This concept was first brought to general attention in 1838.

It was a natural actuate of the many observations that had been made during the early part of the nineteenth and the preceding centuries.

All living things are composed of cells. Very simple organisms such as yeast and bacteria consist of only one cell. They are one-celled or unicellular organisms. A large organism, such as a human being, contains billion upon trillions of cells and is called a multicellular organism. A drop of blood, for instance, contains about forty billion cells. And there are thousands of drops of blood in the average man.

Despite its small size, each cell is a tiny drop of life. Some cells can exist independently, and do, as in the case of bacteria. Human cells, however, have lost that ability. They depend on one another and specialize in one function or another. Some cells specialize in photosynthesis, some in digestion, some in excretion and some in reproduction.

Groups of cells of a similar shape, size and function form a tissue. When tissues of different types are grouped together for a common function they form an organ. Groups of cells, taken all together, are more advanced than single cells, even if the latter are more independent.

The living matter inside a cell is called protoplasm. The protoplasm is divided into parts. Near the center of the cell is a part which is denser and thicker than the rest of the cell. It is the nucleus. The rest of the cell is cytoplasm.

Like any other living things, cells grow and multiply. Most cells multiply by dividing down the middle. Then there are two cells where only one existed a moment before. The cell nucleus is in charge of seeing that cell division takes place properly. The cytoplasm takes care of the day-by-day life of cell. Cells in different parts of the body vary in their shape according to the work they must do. Fat cells are just tiny blocks of fat surrounded by a thin layer of protoplasm. The red cells of the blood are little disks that contain a protein called hemoglobin, which carries oxygen to all other cells of the body. Red blood cells are so simple, they don’t even have a nucleus and so cannot grow or divide.

Nerve cells have irregular shapes with long thread-like fibers sticking out of them. Impulses and sensations travel along those fibers. Muscle cells are long and thin. They can contract into short, thick cells whenever necessary.

Some cells are so specialized that they have abandoned almost everything but their main function. They have even lost the ability to multiply. A baby is born with all the brain cells, for instance, that it will ever have. Still other cells are always growing. The cells of the skin grow and divide throughout life.

B – GROUP

Exercise 8. Find pairs of synonyms, translate them.

Exact, concept, brief, result, immense, to exist, fundamental, tiny, sort, disease, idea, shortly, conclusion, great, to live, basic, kind, illness, similarity, to make a voyage, likeness, precise, to travel, tool, instrument, small.

Exercise 9. Translate into Ukrainian and memorize the synonyms.

to consist of

to be composed of складатися з

to be made up of

1. All living things are composed of cells.

2. Multicellular organisms are made up of a number of cells.

3. The human being is made up of about 50 000 000 000 000 cells.

4. Microorganisms are made up of single cells, they are unicellular organisms.

5. Tissues consist of groups of cells of similar shape, size and function.

Exercise 10. Give Ukrainian equivalents to the following expressions. Find them in the text and make up your own sentences with these expressions.

1. yeast _______________________________________

2. sticking out ________________________________________

3. average man _________________________________________

4. the latter _________________________________________

5. to be in charge of seeing _________________________________

6. throughout life ______________________________________

7. by dividing __________________________________________

8. for instance __________________________________________

9. to be made up of _______________________________________

C – GROUP

Exercise 11. Translate into Ukrainian paying attention to degrees of comparison.

1. Nucleus is denser and thicker than the rest of the cell.

2. Groups of cells, taken all together, are more advanced than single cells.

3. Single cell are more independent than groups of cells taken together.

4. The human being is more complex and advanced than a bacterium.

Exercise 12. Change subordinate clouses to Participle constructions.

1. While he was walking in the street he met his friend.

2. When I rest after my work I read a newspaper.

3. The books were returned to the library when they had been read by students.

4. The instruments will be spoiled if they are left in the open air.

5. After the student had been examined he went home.

D – GROUP

Exercise 13. Answer the following questions.

1. What are the living things composed of?

2. What are unicellular organisms?

3. Which organisms are called multicellular?

4. How many cells does a drop of blood contain?

5. Can human cells live independently?

6. Why have they lost that ability?

7. What does a cell consist of?

8. What are the main functions of a cell?

9. What shapes do different cells of the body have and why?

10. Why cannot red blood cells grow and divide?

11. Which human cells have lost the ability to multiply?

Exercise 14. Describe different kinds of cells completing the sentences by words from the text.

1. Red blood cells are …

2. Muscle cells are …

3. Fat cells are tiny …

4. Nerve cells have …

Exercise 15. Translate the following text in writing paying attention to Participles.

Cells, Tissue, Organs and Systems

With few exceptions, protoplasm is organized into microscopically visible units called cells. Cells are the smallest living units (except for the viruses). They are variously shaped, have a considerable range of size, and are associated in different ways. They all have structural features in common.

In some instances single cells constitute entire organisms, each such cell carrying on all the life processes. Or small numbers of cells may be associated in colonies. In these colonial groups all cells appear similar and have the same function. In other aggregation of cells there is often division of labour, particular cells being more concerned with some life functions than with others.

This division of labour becomes increasingly important in the higher forms of life which have great structural complexity. In these higher plants and animals the cells are organized into tissues, or groups of cells with similar structure and functions. Combinations of tissues make up organs with more or less distinct functions. In the animals, which are functionally more complicated in systems, or groups of organs that are collectively responsible for certain functions.

Exercise 16. Translate the following texts into Ukrainian and then back into English. Compare your version with the original. Pay attention to Participles:

a) 1. He is doing research in the field of biology. 2. While doing research he suggested a new theory. 3. The leading scientists of the world doing research in this field came to the conference. 4. The technology applied improved the quality of the experiment. 5. The result obtained showed that I was right. 6. The invited delegates were told about the work of our institute. 7. The data collected helped me in my work. 8. He was invited to this conference. 9. When invited I always came. 10. Having been invited beforehand he had a lot of time to prepare his report. 11. Having come into the room the lecturer began his lesson. 12. Having used a new method scientists obtained good results. 13. Scientists must concentrate their efforts on the aspects of science having the greatest promise for the future. 14. The results being obtained at this laboratory are of great importance. 15. Being asked to give the material and some pictures for publication he did it with pleasure.

b) 1. The exercises having been written in pencil, we had to rewrite them. 2. The problem having been solved, we could carry on the necessary experiment. 3. Having returned from the expedition he began preparing a report about his work. 4. My friend having returned from the expedition, we shall see him in our laboratory in a few days. 5. He was asked a great many questions, some of them being very difficult to answer. 6. The first part of the work having been finished, the results were published in a scientific journal. 7. Having been shown the journal, he asked his friend if he could lend him the book for a few days. 8. Being well written, the article was short and clear. 9. The article being well written, he read it with pleasure. 10. Our work having been completed, he made a report at the scientific conference of the students. 11. The problem having been approached from different points of view, its practical significance was stressed again. 12. The report having aroused a great interest both among the students and the specialists, the latter took part in the discussion too.

Exercise 17. Are the following statements true or false? Correct the false statements. Use phrases given below.

on the contrary; I don't believe that;

to my mind; it is considered that; as is known

These tiny things never grow. – On the contrary, they eat and grow, travel and multiply.

1. Bodies of both plants and animals consist of cells.

2. The size and shape of plants are different, but their protoplasm are similar.

3. Plastids, the minute cell bodies are in the nucleus.

4. The nucleus is different from protoplasm in that its proteins are less complex.

5. Vacuoles appear only when the cell enlarges.

6. The cells of many flowers are coloured with pigments in the cell sap.

7. The cell wall is surrounded by a thin cellulose layer.

Exercise 18. Fill in the gaps with the following words. Translate the sentences.