Download вариант 2

Прочтите текст и выполните задания после текста.
Пояснения к тексту:
1.
2.
3.
4.
5.
6.
cell – клетка;
nucleus –ядро;
gene – ген;
dye – краска; красящее вещество;
apiece – зд. каждая (клетка);
virus – вирус.
ENZYMES AND GENES
1. The nucleus of the cell is in charge of cell division. Unfortunately, most of
the details of the process are as yet unknown. Still we can describe some of them.
Inside the nucleus are small patches that can react with certain dyes to become
strongly coloured. Biologists noticed them for that reason and called the material in
the patches chromatin from the Greek word for “colour”.
2. In the process of cell division, the chromatin collects into little rods of
varying size. The rods are called chromosomes. In the nuclei of human cells are
forty-six such chromosomes, existing in pairs. There are twenty-three pairs of
chromosomes, in other words. Each kind of creature has its own fixed number of
chromosomes. А rat has thirty-eight chromosomes, а grass-hopper has twenty-four,
and а housefly has only twelve. А crayfish on the other hand, has over two hundred
chromosomes.
3. Before а cell divides, every chromosome lines up in the centre of the cell
and splits in two. The two halves of each chromosome move apart and when the
cell divides, each new cell has а duplicate of all the original chromosomes. It is
these chromosomes that control а cell’s characteristics. A cell’s nature is
determined by the kind of chromosomes it has. Every chromosome is actually а
chain of protein molecules which are called genes. Genes are strung along а
chromosome as beads are in a necklace. The genes have a certain chemical
resemblance to viruses.
4. Each gene is thought to control a single characteristic of an organism.
Every human being has thousands of different genes scattered through its various
chromosomes. Whenever a chromosome splits in two, during cell division, each
gene duplicates itself exactly and both daughter cells get one apiece.
Ex. 1 Определите соответствуют ли данные предложения тексту или нет
(True / False):
1. The nucleus of a cell plays an important role in cell division.
2. The nucleus of a human cell has forty-six pairs of chromosomes.
3. The nature of a cell is determined by the number of chromosomes it has.
4. Genes are thought to control an organism’s characteristics.
Ex. 2 Выберите правильный вариант ответа на следующие
вопросы в соответствии с текстом:
1. What part of a cell is in charge of cell division?
A. The membrane of a cell is in charge of cell division.
B. The nucleus of a cell is responsible for cell division.
C. The cytoplasm of a cell plays a vital role in cell division.
2. How many chromosomes does each kind of creature have?
A. Each kind of creature has as many chromosomes as it needs.
B. All creatures have the same number of chromosomes.
C. Each kind of creature has its own fixed number of chromosomes.
3. What is the nature of a cell determined by?
A. The nature of a cell depends on the kind of chromosomes it contains.
B. The nature of a cell is determined by the number of chromosomes it has.
C. The nature of a cell is characterized by its size.
4. What happens when a chromosome splits in two during cell division?
A. During cell division genes are strung along а chromosome as beads are
in a necklace.
B. During cell division each gene duplicates itself and both daughter cells
get one apiece.
C. During cell division chromatin collects into little rods of varying size.
Ex. 3 Выберите правильный вариант перевода следующих
предложений:
1. In the process of cell division, the chromatin collects into little rods of
varying size.
A. В процессе клеточного деления хроматин собирается в крупные
единицы правильной формы.
B. В процессе клеточного деления хроматин накапливается
маленькими структурами определенной формы.
C. В процессе клеточного деления хроматин образует небольшие
структуры различной формы.
2. When the cell divides, each new cell has а duplicate of all the original
chromosomes.
A. При делении клетки все новые клетки получают удвоенное
количество исходных хромосом.
B. При делении клетки каждая новая клетка приобретает часть
исходных хромосом.
C. При делении клетки каждая новая клетка получает идентичный
набор всех исходных хромосом.
3. Genes are thought to have a certain resemblance to viruses.
A. Гены, как известно, имеют некоторое сходство с вирусами.
B. Полагали, что гены имеют абсолютное сходство с вирусами.
C. Полагают, что гены имеют определенное сходство с вирусами.
Ex. 4 Вставьте в предложения лексические единицы
в
соответствии с текстом:
1. In the nuclei of human cells chromosomes exist in _____.
A. Haves.
B. Units.
C. Pairs.
2. Before cell ______, every chromosome lines up in the centre of the cell and
splits in two.
A. Reproduction.
B. Division.
C. Development.
3. Each chromosome is а chain of protein _____ which are called genes.
A. Cells.
B. Molecules.
C. Rods.
4. Every human being has thousands of different _____ scattered through its
various chromosomes.
A. Genes.
B. Cells.
C. Bases.