Biology as a science Unit I. Seven levels of life organization

B

iology covers a wide field of information over a considerable size range. On the one hand it involves the movements of electrons in photosynthesis and on the other the migrations of individuals around the earth. Within this range it is possible to recognize seven levels of organization, each of which forms the basis of the next. The most fundamental unit is the atom; atoms group to form molecules, which in turn may be organized into cells. Cells are grouped into tissues which collectively form organs, which form organisms. A group of organisms of a single species may form a population.

Unit 1. Atomic organization

Did you know?

The most common element

by number of atoms in the

human body is hydrogen,

63%; Next is oxygen, 25,5%

Essential Vocabulary

Amount to absorb abundant

atom to contain available

calcium to cover considerable

cause to detect charged

cell to destroy deoxyribonucleic (acid)

damage to detect equal

electron to emit neutral

hydrogen to exceed rapidly

ion to except selectively

isomer to exist similar

isotope to gain

loss to involve

matter to maintain

molecule to pass

neutron to promote

nitrogen to release

nucleus to remain

oxygen to spin

particle to trace

property to vaporize

range

sample

species

synthesis

tissue

variety

1. Назовите прилагательные, образованные от существительных:

Cell, hydrogen, ion, molecule, nucleus, synthesis, vein.

2. Дополните соответствия по образцу: cause – to cause;

? --- to absorb;

cover --- ?

? --- to contain;

charge --- ?

? --- to contribute;

existence --- ?

? --- to heat;

synthesis --- ?

? --- to transform.

Аналитическое чтение.

Atoms are the smallest units of a chemical element that can exist independently. They comprise a nucleus which contains positively charged particles called protons, the number of which is referred to as the atomic number. For each proton there is a particle of equal negative charge called an electron, so the atom has no overall charge. The electrons are not within the nucleus, but orbit in fixed quantum shells around it. There is a fixed limit to the number of electrons in any one shell. There may be up to seven such shells each with its own energy level; electrons in the shells nearest to the nucleus have the least energy. The addition of energy, e.g. in the form of heat or light, may promote an electron to a higher energy level within a shell. Such an electron almost immediately returns to its original level, releasing its newly absorbed energy. This electron movement is important biologically in processes such as photosynthesis.

The nucleus of the atom also contains particles called neutrons which have no charge. Protons and neutrons contribute to the mass of an atom, but electrons have such a comparatively small mass that their contribution is negligible. However, the number of electrons determines the chemical properties of an atom.

Grammar 1. Глаголы to be, to have: функции и спряжение во временах Indefinite.

2. Артикли имен существительных.

3. Оборот there + be

4. Времена группы Indefinite Active

1. Найдите в тексте примеры употребления глаголов to be и to have. Определите их функцию в предложении и грамматическое время.

2. Прокомментируйте употребление артиклей в предложениях 1, 3, 6.

3. Найдите в тексте оборот there + be. Определите его грамматическое время, переведите предложения.

4. Измените следующие предложения во временах Indefinite. Составьте вопросительную и отрицательную форму.

a) Atoms comprise a nucleus which contains positively charged particles.

b) An electron immediately returns to its original level.

c) Protons and neutrons contribute to the mass of an atom.

d) The number of electrons determines the chemical properties of an atom.

Summary

Прочтите тексты, пользуясь словарем, найдите наиболее важные в смысловом отношении предложения (фрагменты). Кратко изложите содержание текстов на английском языке (не более 4-5 предложений по каждому тексту).