- •Texts: origin of life. Properties of chemical reactions pre-reading and reading tasks.
- •Origin of life
- •Notes to the text: Aristotle ["xrIs'tq(V)tl]
- •John Tyndall [dZPn tIndl]
- •Comprehension check
- •3. Point out the topic sentence in each paragraph. Language focus Form the derivatives of the words given in the chart below (where possible):
- •Follow-up activities
- •Additional text
- •I. Read and translate the text. Be ready to fulfil the tasks that follow. Properties of chemical reactions
- •Post-reading tasks
- •Grammar exercises
- •Texts: the cell. Cells pre-reading and reading tasks.
- •1. Study the meaning and pronunciation of the following words:
- •2. Make sure you know the following words and word combinations:
- •3. Comment on the headline of the text before reading it. What do you know about the cell? Read the text and point out what information is new for you. The cell
- •Notes to the text:
- •Comprehension check
- •Language focus
- •1. Say it in another way (give synonyms):
- •Follow-up activities
- •Additional text
- •Post-reading tasks
- •Grammar exercises
- •Texts: how the body works. The skin. Seeing. Taste and smell. Hearing. Pre-reading and reading tasks
- •How the body works
- •Comprehension check
- •1. Agree or disagree with the following:
- •2. Answer the questions:
- •Language focus
- •Follow-up activities
- •Additional texts
- •The skin
- •Taste and smell
- •Hearing
- •Imagine that you are making a speech on one of these topics:
- •Grammar exercises
- •Texts: the brain. Pre-reading and reading tasks.
- •1. Practise the pronunciation and study the meaning of the words:
- •The brain
- •Comprehension check
- •1. Express your agreement or disagreement with the following:
- •Language focus.
- •3. Translate the following sentences from Russian into English:
- •Follow-up activities
- •Additional text
- •The brain
- •Post-reading tasks
- •Grammar exercises
- •Texts: the nerves. The nervous system. Pre-reading and reading tasks
- •The nerves
- •Comprehension check
- •Language focus
- •3). Translate the sentences into English using the vocabulary of the unit:
- •Follow-up activities
- •Additional text
- •The nervous system
- •Post-reading tasks
- •Grammar exercises
- •Texts: the skeleton and muscles. Bones and muscles. Pre-reading and reading tasks
- •The skeleton and muscles
- •Comprehension check
- •Language focus
- •Follow-up activities
- •Additional text
- •Bones and muscles
- •Post-reading tasks
- •Grammar exercises
- •Texts: the blood system. Blood. Pre-reading and reading tasks
- •2. Try to guess the meaning of the following words and word combinations:
- •3. Read the text carefully to fulfil the tasks that follow. The blood system
- •Comprehension check
- •Language focus
- •In each box below match the words which are: a) similar or b) opposite in meaning:
- •Follow-up activities
- •Additional text
- •Post-reading tasks
- •Grammar exercises
- •Texts: the digestive system. Nutrition. Pre-reading and reading tasks
- •2. Make sure you know the meaning of these words and word combinations:
- •3. Read the text carefully to fulfil the tasks that follow. The digestive system
- •Comprehension check
- •Language focus
- •Follow-up activities
- •Additional text
- •Nutrition
- •Post-reading tasks
- •Imagine that you are making a speech on the topic “Nutrition”. Grammar exercises
- •Pre-reading and reading tasks
- •Viruses and subviruses
- •Viruses
- •Subviruses
- •Comrehension check
- •Viruses contain
- •Viruses do not
- •Viruses that attack only bacteria are known as … .
- •It is possible that viruses may be moving genetic material from
- •Viruses may prove, in some cases, to be the simplest of
- •3. Think of 5-7 statements that would contradict the contents of the text. Language focus
- •3. Define the following terms:
- •4. Match the first half of a sentence in column a with the appropriate second half in column b:
- •5. Put the parts of the sentences in the right order:
- •Unit 10
- •Text: monera pre-reading and reading tasks
- •1. Make sure you know the following words:
- •2. Read and translate the text. Monera
- •Comprehension check
- •Follow-up activities
- •1. Prepare a dialogue with your partner discussing:
- •Grammar exercises
- •Unit 11
- •Text: protista. Pre-reading and reading tasks
- •1. Make sure you know the following words:
- •2. Read and translate the text. Protista
- •Comprehension check
- •1. Choose the right variant for the multiple-choice statements.
- •1. All protists
- •2. Ask questions revealing the main points of the text.
- •3. Think of 5-7 statements that would contradict the contents of the text. Language focus
- •Follow-up activities
- •1. Prepare dialogues discussing: a) general information about the kingdom Protista; b) primitive protists; c) true algae; d) unicellular algae.
- •2. Prepare a report on the topic under discussion. Grammar exercises
- •Unit 12
- •Text: fungi pre-reading and reading tasks
- •1. Make sure you know the following words and word combinations:
- •Comprehension check
- •7. Many true fungi have mycelia that grow in a close, intimate manner with plant roots, where the plants benefit by receiving … and … while the fungus benefits by receiving nutritious … .
- •8. Lichens involve the close association of a … and a … .
- •9. When the hyphae of a fungus grow around, sometimes in between, and even within living plant root cells, the association is … .
- •2. Questions to think about.
- •3. Think of 5-7 statements that would contradict the contents of the text. Language focus
- •1. Match the words that are: a) similar and b) opposite in meaning:
- •1. Name and describe: a) the major groups of fungi; b) the ways of fungal nutrition.
- •2. Prepare a report on the topic under discussion. Grammar exercises
- •Unit 13
- •Text: plant kingdom: plantae. Pre-reading and reading tasks.
- •Plant kingdom: plantae
- •Comprehension check
- •Language focus
- •Follow-up activities
- •1. Explain the terms: Chlorophyta, Phaeophyta, Rhodophyta.
- •Grammar exercises
- •Unit 14
- •Texts: coniferophyta: conifers. Anthophyta / angiosperms: flowering plants. Pre-reading and reading tasks
- •2. Read and translate the text. Coniferophyta: conifers
- •Anthophyta / angiosperms: flowering plants
- •Comprehension check
- •2. Ask questions revealing the main points of the text.
- •3. Think of 5-7 statements that would contradict the contents of the text. Language focus
- •1. Match the words that are: a) similar and b) opposite in meaning:
- •Follow-up activities
Unit 10
GRAMMAR: MODAL VERBS.
Text: monera pre-reading and reading tasks
1. Make sure you know the following words:
trail |
[treIl] |
след |
to decompose |
["di:kqm'pqVz] |
разлагаться, гнить |
corpse |
[kO:ps] |
труп |
to procure |
[prq'kjVq] |
добывать |
to thrive (throve,thriven) |
[TraIv] |
пышно расти, разрастаться |
to coil |
[kOIl] |
закручивать(ся) |
to loop |
[lu:p] |
перекручиваться, образовывать петли |
versatility |
["vE:sq'tIlItI] |
многосторонность |
tuft |
[tAft] |
пучок |
conjugation |
["kPndZV'geIS(q)n] |
соединение |
dormant |
['dO:mqnt] |
находящийся в состоянии покоя |
desiccation |
["desI'keIS(q)n] |
высушивание, сушка |
2. Read and translate the text. Monera
Unlike viruses and subviruses, which are not cellular, the members of the kingdom Monera, including bacteria and blue-green bacteria (sometimes called cyanobacteria, or blue-green algae), are composed of true cells. Monerans are all prokaryotic; that is, their cells lack most organelles, they do not have a membrane-bound nucleus, and most occur as single-celled organisms.
Of the other 15,000 described species, many exist as a series of cells occurring in long filaments or as more complex colonies. Scientists are discovering bacteria that form complex communities, hunt prey in groups, and secrete chemical trails for the directed movement of thousands of individual bacterial cells.
In comparison to most single-celled eukaryotes, individual bacterial cells are smaller and far more abundant, representing a remarkably important component of nearly all ecosystems. Without bacteria, life on earth could not exist as we know it. Bacteria represent some of the most important groups of decomposers; without them, dead organisms would not decay properly. Many nutrients would remain locked up in corpses forever. Geochemical recycling of the earth’s nitrogen, carbon, and sulfur, which are critical to life, would not occur without bacteria. Chemicals such as nitrates, which certain plants use for protein synthesis, are produced by some species of bacteria. Certain bacteria are heterotrophic; that is, they procure their food by feeding on organic material formed by other organisms. Other species of bacteria are photosynthetic, capable of synthesizing their organic molecules from inorganic components, using the energy from the sun. One group of bacteria, the mycoplasmas, are the smallest known cells that grow and reproduce without needing a living host. Their diameters range from 0.12 to 0.25 micrometers.
Probably because of the small size of most types of bacteria, their rapid rate of cell division, remarkable metabolic versatility, and ability to live practically anywhere, they are the most numerous organisms on earth. Under optimal conditions, a population can double in size every 20 or 30 minutes. Species of bacteria are found thriving on icebergs, in hot springs, at the bottom of the oceans, in freshwater, on land, in the soil, and even in aviation fuel.
Although most bacteria use oxygen in their metabolic processes, there are many species that use alternative pathways, surviving perfectly well without any oxygen. Some species have the ability to form spores, which are inactive, thick-walled forms that survive for long periods without water or nutrients in what otherwise would be unfavorable conditions.
Bacteria were first discovered in 1676, but it was not possible to learn very much about them. In the nineteenth century, Louis Pasteur went as far as was possible without the aid of the subsequently developed electron microscope or advanced biochemical techniques, which enabled later researchers to study these small organisms in considerably more detail.
Being prokaryotes, bacteria have cells that differ from eukaryotes in the following ways.
1. Cell walls. Prokaryotic cell walls are composed of a polymer of glucose derivatives attached to amino acids. This substance is termed a mucocomplex. Some bacteria have an additional outer layer of a polymer composed of lipid and sugar monomers, which is termed lipopolysaccharide. Many bacteria can secrete polysaccharides that allow them to stick to things. Cell walls of cyanobacteria (blue-green bacteria) tend to be covered with gelatinous material.
2. Plasma membrane. Inside the cell wall of some bacteria is a plasma membrane that coils and loops, creating a unique structure known as the mesosome, which may be important in cell division.
3. Other internal membranous structures. Some prokaryotes have internal membranous structures containing photosynthetic pigments and related enzymes. Of the aerobic bacteria, those that use molecular oxygen for cellular respiration, some have internal membrane systems containing respiratory enzymes.
4. Ribosomes. The only organelles that consistently occur in prokaryotes are ribosomes, on which messenger RNA (mRNA) is found. The mRNA carries instructions from the genes to the ribosomes, where protein synthesis occurs. Prokaryotic ribosomes are smaller than those found in eukaryotic cells.
5. Flagella. Some bacteria are flagellated, meaning, they have whiplike appendages, extending singly or in tufts, that propel the cells. The flagella of higher organisms consist of a hollow cylinder containing nine pairs of fibrils surrounding two central fibrils. A bacterial flagellum consists of a single fibril of contractile protein.
Prokaryotic DNA (deoxyribonucleic acid) differs from eukaryotic DNA in that it is associated with different proteins. It also differs from eukaryotic DNA in that it is not paired, but is circular. Circular DNA molecules consist of only about one thousandth the DNA found in eukaryotic cells.
Most bacterial cells reproduce by the simple cell division, binary fission. Neither mitosis nor meiosis ever occurs in prokaryotic cells; however, some prokaryotes have a sexual process that transfers material between cells. Occasionally these bacterial cells will transfer DNA to another cell, after which some of the new DNA will replace the recipient's DNA. To date, nothing analogous to a sexual system has been observed in any of the cyanobacteria.
There are three methods by which genetic material may be transferred between bacteria.
1. Transformation. One bacterial cell breaks; its DNA can be taken up by another bacterial cell.
2. Conjugation. Two bacterial cells come together and are joined by a protein bridge, a pilus, through which DNA fragments pass from cell to cell.
3. Transduction. A bacteria-attacking virus, known as a bacterial virus, or bacteriophage, carries bacterial DNA from one bacterial cell to another.
Each of the three methods can result in the transfer of DNA fragments from one bacterial cell to another. During the transfer, sometimes homologous DNA fragments, those containing the same type of genetic information, are substituted in the recipient's circular DNA without a net increase or decrease in the total amount of circular DNA.
It is not certain how important genetic recombination is for prokaryotic evolution. However, despite the fact that mutations (inheritable changes in the organism's genetic material) occur infrequently, prokaryotes do have a high degree of genetic variability and therefore evolve quickly. When it exists, their rapid rate of evolution is usually attributed to their great numbers, and their incredible reproductive rate, as well as mutations and genetic recombinations. Knowledge of such DNA recombination led to research using viruses that transmit DNA fragments to other types of organisms. This research is expected to lead to human gene therapy.
Many prokaryotes are also capable of producing a dormant stage known as a spore. Unlike the spores of other organisms, this is not a reproductive unit. Rather, bacterial spores function wholly as units that contain stored food and are highly resistant to desiccation, as well as to extremely hot and cold temperatures. Bacterial spores have been shown to survive temperatures as cold as -252°C, and some may be able to live for thousands of years. When conditions become favorable, the bacterial spore germinates into a new cell.