The Humal Cell

The cell is the basic structural, functional and biological unit of all known living organisms, and is often called the "building blocks of life". The study of cells is called cell biology. Some organisms, such as bacteria, are unicellular, consisting of a single cell. Other organisms, such as humans, are multicellular. There are two types of cells, eukaryotes, which contain a nucleus, and prokaryotes, which do not. Human cell is eukaryotsic cell. They vary in size, but all are quite small and have different lifespan.

Structurally each of the human cells is divided into two main parts, the nucleus and the cytoplasm. The nucleus is a large, spherical structure, surrounded by cytoplasm. It is a most important structure because it contains the cell’s genetic material and the structures that control cell division and reproduction. The nucleus is present in all mammalian cells except red blood cells and keratinized cells. Very frequently nuclei serve as the basis for diagnosing a pathologic process. Aside from their staining characteristics, which make them useful to histologists, nuclei are important biologically.

A double membrane, the nuclear membrane, separates the nucleus from the cytoplasm. The cytoplasm is a fluid material which contains many well-organized structures, called organelles and inclusions. Inclusions are stored nutrients, secretory products, and pigment granules.

The cell membrane is the thin membrane which surrounds the cytoplasm. The cellular membrane contains lipid and protein molecules. The membrane also contains tiny holes, called pores. The cellular membrane prevents leakage of the inner cellular structures into the surrounding environment. Serving as a highly selective barrier, the membrane keeps certain unwanted substances from entering the cell but admits other substances that are necessary for maintaining cellular life.

The body is composed of many different types of cells, each with its own structure and function. Some, such as white blood cells, move freely, unattached to other cells. Others, such as muscle cells, are firmly attached one to another. Some cells, such as skin cells, divide and reproduce quickly. Some cells, especially glandular cells, have as their primary function the production of complex substances, such as a hormone or an enzyme.

Exercise 6. Answer the following questions:

1. What is a cell?

2. How is each cell divided?

3. What is the role of the nucleus?

4. What separates the nucleus from the cytoplasm?

5. What does the cellular membrane contain?

6. How does the membrane serve?

7. Do all cells in the body have the same function?

8. What is the study of the cell called?

Exercise 7. Find English equivalents of the following word combinations in the text:

Біологічна одиниця, живий організм, види клітин, основна функція, складні речовини, сферична структура,запобігати витіканню, крихітний отвір, варіюватися у розмірі, генетичний матеріал, тривалість життя, переміщуватися вільно, патогенні процеси, характеристика фарбування, підтримувати життя клітини, містить ліпідні і білкові молекули, служити як бар’єр.

Exercise 8. Match the terms with their definitions:

cytoplasm membrane nucleus pore eukaryote organelle prokaryotes cell

a) unicellular organism having cells lacking membrane-bound nuclei; b) tiny hole admitting passage of a liquid (fluid or gas); c) the basic structural and functional unit of all organisms; d) a part of the cell containing DNA and RNA and responsible for growth and reproduction; e) one small part of a cell; f) the protoplasm of a cell contained within the cell membrane but excluding the nucleus: contains organelles and other inclusions; g) a thin, flexible layer of tissue that covers, lines, separates, or connects cells or parts of an organism; h) an organism with cells characteristic of all life forms except primitive microorganisms such as bacteria; i.e. an organism with `good' or membrane-bound nuclei in its cells.

Exercise 9. Complete the sentences and translate them:

1. The inclusions contain food and secretory and... .

2. Structurally, each of the cells is divided into two parts,... .

3. Very frequently nuclei serve as the basis for diagnosing ... .

4. A double membrane separates the nucleus from ... .

5. The cellular membrane contains lipid and ... .

6. The membrane keeps certain unwanted substances… .

7. The body is composed of many different types of cells... .

8. The glandular cells have primary function as the production of … .

Exercise 10. Agree or contradict the following statements:

1. Human cell is eukaryotsic cell.

2. The nuclear membrane separates the nucleus from the cell.

3. The cell is often called the "building blocks of life".

4. The cellular membrane contains lipid and organelles.

5. Inclusions contain the cell’s genetic material.

6. All cells in the body produce insulin.

7. Human cells are divided into three main parts.

8. The membrane keeps certain unwanted substances from entering the cell.

Exercise 11. Translate the sentences into English:

1. Структурно кожна клітина ділиться на дві основні частини.

2. Ядро - це велика сферична структура, оточена цитоплазмою.

3. Дуже часто ядро є основою для діагностики патологічного процесу.

4. Ядерна оболонка відокремлює ядро від цитоплазми.

5. Клітинна оболонка - це тонка оболонка, що оточує цитоплазму.

6. Клітинна оболонка запобігає витоку внутрішніх клітинних структур в навколишнє середовище.

7. Клітини розрізняються за розміром та мають різну тривалість життя.

8. Ядро містить генетичний матеріал клітини і структури, які контролюють розподіл і відтворення клітин.

Exercise 12. Put questions to the underlined words:

1. The cell membrane is the thin membrane which surrounds the cytoplasm.

2. Nuclei are important histological and biologically.

3. The nuclei are present in all mammalian cells except red blood cells and keratinized cells.

4. Very frequently nuclei serve as the basis for diagnosing a pathologic process.

5. The nuclear membrane separates the nucleus from the cytoplasm.

6. The inclusions contain food and secretory and pigment granules.

7. The cellular membrane prevents leakage of the inner cellular structures into the surrounding environment.

8. Muscle cells are firmly attached one to another.

Exercise 13. Choose the correct verb and translate the sentences:

1. Ann have/has studied very much this term.

2. The patient have/has sustained a trauma.

3. These affected tissues hasn’t/haven’t recovered for a long time.

4. He hasn't/haven’t wiped the skin around the burn with alcohol yet.

5. The sanitary transport have/has just delivered an injured person from the spot of accident.

6. I have/has been his patient since 2009.

7. They have/has just seen the nurse in the hall.

8. I have/has broken the thermometer.

Exercise 14. Open the brackets using the verbs in the Present Perfect and translate into Ukrainian:

1. The nurse just (to give) analgesics to the patient suffering from the muscle pain.

2. Nelly never (to visit) a dentist.

3. Viruses grow when they (to invade) living cells.

4. When the tumor (not to spread) beyond the lymph nodes, surgery may be effective.

5. Some oncogenic viruses already (to be investigated).

6. Experiments (to show) that certain viruses can cause cancer.

7. We already (to learn) a lot of English words.

8. He just (to do) something for us.

Exercise 15. Put the sentences into the correct order to explain the term “cell”:

___Structurally each of the human cells is divided into two main parts, the nucleus and the cytoplasm.

___The body is composed of many different types of cells, each with its own structure and function.

___The study of cells is called cell biology.

___The cell is the basic structural, functional and biological unit of all known living organisms.

___The nuclear membrane separates the nucleus from the cytoplasm.