IV. Choose the correct option. In some cases more than one answer is possible



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ЗНАЕТЕ ЛИ ВЫ?

IV. Choose the correct option. In some cases more than one answer is possible



1. Carbohydrates are substances which include:

a) carbon, nitrogen and water; c) carbon, oxygen and hydrogen;

b) oxygen, hydrogen and water; d) carbon, oxygen and water.

2. To the carbohydrate group belong such substances as

a) sugars, starch and glycogen; c) glycogen, cellulose and dextrin;

b) cellulose, enzymes and dextrin; d) oils, sugars and starch.

3. Different organisms can store energy in:

a) cellulose and lipids; c) glycogen and lipids;

b) starch and triglycerides; d) triglycerides and glycogen.

4. Lipids do not dissolve in:

a) ether; c) water;

b) organic solvents and water; d) alcohol and other organic solvents.

5. Lipids do not perform the following functions:

a) participate in the regulation of transport across the cell membrane;

b) catalyze important reactions taking place in the cell;

c) serve as important energy reserves;

d) form protective coatings for plant leaves.

6. Proteins are important because they:

a) serve as structural material for organisms;

b) provide protection from a wide range of infectious agents and toxic substances;

c) store hereditary information and pass it to next generations;

d) can be used as energy reserves.

7. Nucleic acids are believed to have been formed

a) at the time when the most primitive living forms appeared on the earth;

b) together with the first multicellular organisms;

c) 4,5 billion years ago;

d) in the primordial soup.

V. Think of possible questions for the following answers

1. They are produced by green plants and by bacteria in the process of photosynthesis.

2. The most important of them is glucose.

3. These are cellulose and hemicellulose.

4. Animals use glycogen for this purpose.

5. No, they can only dissolve in alcohol, ether and other organic solvents.

6. They were discovered in 1838.

7. 30,000.

8. This problem is still being researched.

9. It resembles a double helix.

VI. In the text “Macromolecules” find the words with the following meanings. Use these words in the sentences of your own

1 to unite into a chemical compound;

2 marked by extraordinarily great size, number, or degree;

3 any of various organic compounds characterized by an oxygen atom attached to two carbon atoms;

4 a usually liquid substance capable of dissolving or dispersing one or more other substances;

5 being most frequent or common; prevailing;

6 a tiny globe or ball especially of a liquid; a droplet;

7 the shortening and thickening of a functioning muscle or muscle fiber;

8 having a spiral form;

9 distinctive among other examples or cases of the same general category.

VII. Find the following words and expressions in the text “Macromolecules”. Explain the differences in their meanings and usage. Use these words and expressions to fill in the gaps in the sentences below

a) Constitute; make up.

b) Contain; include; be composed of; consist of.

1. Each cell typically _______ a central, usually spherical, nucleus and an outermore heterogeneous region, termed the cytoplasm.

2. Up to 70% of your total body weight is _______ of water.

3. Cigarettes which _______ less than 0.8 mg nicotine can be classified as "light".

4. Symptoms of the disease _______ tiredness and loss of memory.

5. Water is ________ hydrogen and oxygen.

6. Doctors are struggling to _______ the epidemic.

7. The environment of an organism also _______ the other organisms in its surroundings.

8. It is sometimes difficult to believe that the different groups living within our borders ________ a single society.

9. Hereditary information is carried by large molecules known as genes which are ________ nucleic acids.

10. The rise in crime ________ a threat to society.

11. Human cells are in many fundamental respects similar to those that ________ all the other animals and plants on the Earth.

GRAMMAR IN USE: WORD FORMATION 1

I. Look at the words below. They are all the derivatives of one word – solve. Explain the meaning of each word. What morphological means have been used to produce these words? What other means of word formation do you know?

Solvent; insoluble; dissolve; soluble.

II. Regard the suffixes enlisted below. What parts of speech are formed by means of these suffixes? Find the words containing such suffixes in the text. What do they mean?

-Ance/-ence; -ity; -ness; -ment; -ion/-sion/-tion; -age; -sys; -y; -ty; -ly; -(a)ble; -ive; -en; -ful;-er/-or; -ish; -less.

III. Fill in the following table as in the model

verb noun adjective adverb
dissolve solute; solution soluble; insoluble ---
contract      
function      
reproduce      
store      
maintain      
diversify      
connect      
recognize      
compose      
generate      

IV. Fill in the spaces in the following text using a suitable form of the word given at the end of the lines. The first is given as an example

Any of the organic compounds required by the body in small amounts for (0) metabolism, to protect health, and for proper (1)______ are referred to as vitamins. Vitamins also assist in the (2)______ of hormones, blood cells, nervous-system chemicals, and (3)______ material. The various vitamins are not (4)______ related, and most differ in their (5)______ actions. They generally act as (6)______, combining with proteins to create metabolically (7)______ enzymes that in turn produce hundreds of (8)______ chemical reactions throughout the body. Without vitamins, many of these (9)______ would slow down or cease. The intricate ways in which vitamins act on the body, however, are still far from clear. metabolic (0) grow (1) form (2) gene (3) chemical (4) physiology (5) catalize (6) act (7) importance (8) react (9)

 

LISTENING COMPREHENSION

I. Listen to a fragment of a lecture about DNA structure. Say whether the following statements are true or false according to the text on the tape. Before listening discuss the meaning of the words in the box below with your classmates or teacher

nucleotides nitrogen base complementary base pairing thriving deoxyribose double helix junk

k) Nucleotides are the constituent parts of DNA molecules.

l) Each nucleotide is made up of two main components.

m) There are four types of bases in the DNA structure: cytosine, guanine, thymosine, and adenine.

n) The DNA molecule resembles a double helix or a “ladder” in which the “sides” are made up of bases and the “rumps” consist of phosphate and sugar molecules.

o) The bases in the DNA combine randomly with each other.

p) The mode of base pairing is very important for DNA replication and storage of genetic information.

q) An average human gene includes 100 bases.

r) 98% of a DNA molecule is considered “junk” and useless.

II. Listen to the following piece of information about cellulose. Fill in the missing words or phrases

Cellulose is the (1)____________ of the cell wall of all plant cells. In plants, cellulose is normally combined (2)____________ or gummy substances. With some exceptions among insects, true cellulose is not found (3)____________. Microorganisms in the digestive tracts of (4)____________ break down the cellulose into products that can then be absorbed. Cellulose is insoluble in (5)____________ and may be readily separated from the other (6)____________. Depending on its concentration, sulphuric acid acts on cellulose (7)____________, soluble starch, or amyloid; the last is a form of starch (8)____________ of parchment paper. When cellulose is (9)____________ and then exposed to the fumes of carbon disulfide, the solution (10)____________. Rayon and cellophane are cellulose regenerated from such solutions. (11)____________ are spun into fine filaments for the manufacture of some fabrics and are also used for (12)____________, as a substitute for glass, for the manufacture of safety glass, and as (13)____________. Cellulose ethers are used in paper sizings, adhesives, (14)____________, and (15)____________.

WRITING AND SPEAKING

Write a summary of the text “Macromolecules” in 200 words using the vocabulary of Lesson 1. Get ready to present it in class


Lesson 2

CELL AS A BASIC UNIT OF LIFE

PRE-READING TASKS

I. Answer the following questions

· What meanings of the word “cell” do you know?

· Why do you think the basic unit of life was called the cell?

· What do you know about cells as units of life?

II. Listen to the following words and practice their pronunciation

Virus; totipotent; subcellular; micrometer; algae; neuron; prokaryotic; eukaryotic; Monera; nucleus; nuclei; nucleoid; fungus; fungi; plasma membrane; cytoplasm; minute.

READING COMPREHENSION AND VOCABULARY DEVELOPMENT



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