Match a title to the paragraph.

How they move
Where they're found
What they eat
What they look like
Classification
Early origins
Bacteria

 

Answer the questions to Text 1.

1. What place do Bacteria have in taxonomy?

2. Tell a few words about evolution and early life of Bacteria.

3. What shapes do they have?

4. Where do they live?

5. How do they move?

 

Read the texts using your dictionary.

Retell one of the texts.

Text 2

Bacteria electrifying modern life

Batteries made with microbes could help generate power by cleaning up organic waste at the same time.

Sewage is loaded with energy-rich sugars that researchers have struggled for years to convert into useful power. To do so, investigators have experimented with nature's experts on breaking down waste — bacteria.

Scientists have experimented with a variety of bacteria, but there is one kind that looks very promising and which is naturally found in many soils and sediments. Geobacter grows by breaking down organic materials and transferring electrons pretty much onto anything that looks like iron. When attacking environmental pollutants such as aromatic hydrocarbons, Geobacter can break down some 90 percent. All in all, systems incorporating Geobacter can recover up to nearly all the electrons within sewage.

Still, all the energy that bacteria could generate from wastewater could help power the considerable needs of wastewater treatment. For instances, in the United States, roughly 33 billion gallons of wastewater are treated daily for an annual cost of more than $25 billion, and some 1.5 percent of the electricity produced every year goes into wastewater treatment alone.

Aside from wastewater, another potentially vast source of energy that bacteria could exploit are the organic chemicals in ocean mud. Although humanity already taps into some of this fuel in the form of petroleum, most of this energy reservoir remains beyond reach because it is not nearly as easy to extract and use as oil.

Organic matter keeps on raining down onto marine sediments as organisms die, so the idea is that marine sediments could basically be a perpetual system for powering electronic devices.

In terms of advancing these microbial systems further, scientists have experimented with bacteria in terms of genetic engineering. So far they have managed to double power output.

 

Text 3

How bacteria become drug resistant

Once in every several hundred million cell divisions a mutation makes a bacterium immune to an antibiotic drug. The mutation alters the bacterium's genetic code and thus its ability to use certain chemicals for its life activities. Mutations can be caused by the radiations from outer space that stream into the Earth's atmosphere, as well as by some atmospheric chemicals. As a result of the mutation, all bacteria that stem from the immune germ will be resistant to the drug unless any of them undergoes a mutation that makes the strain susceptible again. Hence, whenever a new antibiotic is developed, there will be a chance that bacteria will develop an immunity against it. But because mutations are fairly rare, doctors have a good chance of fighting a bacterial disease with the new drug before future strains become resistant.

Some members of a bacterial strain are resistant to certain drugs naturally. In the course of time they can eventually become selected through evolutionary forces to become the dominant drug-resistant forms of a pathogenic strain.

More importantly, some bacteria can pass on their drug resistance to bacteria of another strain by “infection.” Since the passing of resistance factors does not depend upon the lengthy process of mutation, it poses a much greater problem of drug immunity. As a consequence, doctors often must prescribe more than one antibiotic to fight certain diseases in the hope that this will slow bacterial resistance.

 

The text for translation into English.

Text 4

Бактерии

Бакте́ рии—группа (царство) прокариотных (безъядерных) микроорганизмов, чаще всего одноклеточных. К настоящему времени описано около десяти тысяч видов бактерий и предполагается, что их существует свыше миллиона.

Впервые бактерий увидел в оптический микроскоп и описал голландский натуралист Антони ван Левенгук в 1676 году. Как и всех микроскопических существ он назвал их «анималькули». Название «бактерии» ввёл в употребление Христиан Эренберг в 1828.

Луи Пастер в 1850-е положил начало изучению физиологии и метаболизма бактерий, а также открыл их болезнетворные свойства. Дальнейшее развитие медицинская микробиология получила в трудах Роберта Коха, которым были сформулированы общие принципы определения возбудителя болезни.

Подавляющее большинство бактерий одноклеточны. По форме клеток они могут быть шаровидными (кокки), палочковидными (бациллы), извитыми (вибрионы) и т.д. Формой определяются такие способности бактерий, как прикрепление к поверхности, подвижность, поглощение питательных веществ.

Из обязательных клеточных структур выделяют три: нуклеоид, рибосомы, цитоплазматическая мембрана (ЦПМ).

Вся необходимая для жизнедеятельности бактерий генетическая информация содержится в одной ДНК (бактериальная хромосома). Она в одной точке прикреплена к ЦПМ и помещается в структуре обособленной, но не отделённой мембраной от цитоплазмы, и называемой нуклеоид. ДНК в развёрнутом состоянии имеет длину более 1 мм.

Размеры бактерий в среднем составляют 0, 5-5 мкм. В то же время к бактериям относятся самые мелкие из имеющих клеточное строение организмов. Mycoplasma mycoides имеет размеры 0, 1-0, 25 мкм, что соответствует размеру крупных вирусов, например, табачной мозаики или гриппа.

Многие бактерии подвижны. Имеется несколько принципиально различных типов движения бактерий. Наиболее распространено движение при помощи жгутиков. Другим типом движения является скольжение бактерий, не имеющих жгутиков, по поверхности твёрдых сред. Наконец, бактерии могут всплывать и погружаться в жидкости, меняя свою плотность, наполняя газами или опустошая аэросомы.

Часть из них может синтезировать все необходимые им органические молекулы из неорганических соединений (автотрофы), другие же требуют готовых органических соединений, которые они способны лишь трансформировать (гетеротрофы).

 

 

Speaking and writing

12.Make a report about any bacterium you find interesting and unusual. Write a plan first and do not forget to mention the bacterium`s

appearance

habitat

feeding habits

way of reproduction.

 

Choose any of the following ideas (or propose your own), find information and write an essay (150-250 words).

The origin of bacteria.

Harmful bacteria.

Useful bacteria.

Extraordinary abilities of bacteria.

 

 

 

Unit 3

Тема урока Amphibia текст 1Class Amphibia текст 2 A few facts about amphibian behaviour текст 3TheRed-eyed tree frog текст 4Красноглазые квакши текст 5 Класс Амфибии

 

Words

1.	dweller	n. a person or animal that lives in a particular place
2.	gland	n. an organ in the human or animal body which secretes particular chemical substances for use in the body or for discharge into the surroundings
3.	distinction	n. a clear difference or separation between two similar things
4.	drought	n. a long period of dry weather when there is not enough water for plants and animals to live
5.	ailment	n. an illness that is not very serious
6.	exceed	v. to be greater in number or size than a quantity, number, or other measurable thing
7.	existence	n. the fact or state of living or having objective reality
8.	wart	n. a small hard raised part on someone's skin
9.	exploit	n. a brave and exciting adventure that someone has had v. to use something fully and effectively
10.	extant	adj. still existing in spite of being very old
11.	hatch	v. if an egg hatches, or if it is hatched, it breaks, letting the young bird, insect etc come out
12.	horny	adj. something that is horny is hard, strong, and made of horn or of a hard substance like horn.
13.	irritate	v. to make someone feel annoyed or impatient, especially by doing something many times or for a long period of time
14.	avoid	v. to stay away from someone or something, or not use something
15.	limb	n.an arm or leg of a person or a four-legged animal or a bird`s wing
16.	newt	n. a small slender-bodied amphibian with lungs and a well-developed tail, typically spending its adult life on land and returning to water to breed
17.	poison	n. poison is a substance that harms or kills people or animals if they swallow it or absorb it v. to make land, rivers, air etc dirty and dangerous, especially by the use of harmful chemicals
18.	prey	n. an animal, bird etc that is hunted and eaten by another animal, predator
19.	distinguish	v. to recognize and understand the difference between two or more things or people, differentiate
20.	require	v. to need for a particular purpose; depend on for success or survival
21.	rough	adj. having an uneven or irregular surface; not smooth or level
22.	tail	n. the part that sticks out at the back of an animal's body, and that it can move
23.	burrow	v. (of an animal) make a hole or tunnel, esp. to use as a dwelling
24.	eject	v. to force or throw something out, typically in a violent or sudden way
25.	leap	v. to jump high into the air or to jump in order to land in a different place
26.	thaw	v. if ice or snow thaws, or if the sun thaws it, it turns into water
27.	toad	n. a tailless amphibian with a short stout body and short legs, typically having dry warty skin that can exude poison
28.	tadpole	n. a small creature that has a long tail, lives in water, and grows into a frog or toad
29.	spawn	v. if a fish or frog spawns, it produces eggs in large quantities at the same time
30.	venom	n. poisonous fluid secreted by animals such as snakes and scorpions and typically injected into prey or aggressors by biting or stinging

 

 

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