Post-reading tasks:

Task 1. Answer the following questions.

1. What did Aristotle concluded twenty three hundred years ago?

2. What are the initial substances of photosynthesis?

3. What is photosynthesis?

4. How does carbon dioxide enter the leaf?

5. What are the final substances of photosynthesis?

6. What is sugar transformed to?

7. What is the energy of photosynthesis?

8. What is visible spectrum?

9. Can any plants synthesize food at fool moon?

10. How may the degree of saturation of plant tissues modify the rate of photosynthesis?

Task 2. Say if the following statements are correct. If not, give the right variant.

1. Ch. Darwin concluded that green plants obtain food from the soil.

2. The initial substances used in photosynthesis are water and carbon dioxide and the final products are sugar and oxygen.

3. Carbon dioxide enters the leaf from the atmosphere below the soil.

4. Oxygen passes through the stomata into the inner atmosphere.

5. Sugar is transformed to other types of food.

6. Red, orange, yellow and white light is the most effective in photosynthesis.

7. Any artificial light that emits useful rays may start photosynthesis.

8. And only deep-sea algae can synthesize food at such low intensities.

9. In the morning photosynthesis attains a maximum rate.

10. When plants begin to wilt, photosynthesis is increased.

Task 3. Fill in the gaps with the appropriate words and word combinations.

1. A number of experiments were conducted by different … .

2. During the hours of darkness … occurred.

3. One of the … is water.

4. Water moves up from the soil through … into the veins of the leaf.

5. Under natural conditions the energy … is sunlight.

6. The degree of … of plant tissues may modify.

7. No … is made from … and water in green plants deprived of light.

8. Red, orange, yellow and blue light is the most effective in … .

9. The lowest … at which photosynthesis will occur is that of full moon.

10. Later in the day the rate of photosynthesis … .

Task 4. Match the terms with their definitions.

1. photosynthesis	a) the condition of being full
2. oxygen	b) the smallest structural unit of an organism
3. saturation	c) one of the minute pores in the epidermis of a leaf or stem through which gases and water vapor pass
4. carbon dioxide	d) radiant energy that we see as light
5. stomata	e) the process of making sugar in the green parts of plants
6. sunlight	f) one of the final products of photosynthesis which can be transformed to other types of food
7. visible spectrum	g) a clear, colorless, odorless, and tasteless liquid, essential for most plant and animal life
8. sugar	h) the element with atomic number 8 and represented by the symbol O
9. water	i) the energy of photosynthesis under natural conditions
10. cell	j) a colorless, odorless, incombustible gas, formed during respiration, combustion, and organic decomposition

Task 5. Translate the following words and word combinations given in brackets.

1. Earlier scientists thought that plants (получают пищу) from the soil.

2. Different investigators (проделали серию опытов) and came to the conclusion that plants (синтезируют собственную пищу).

3. Carbon dioxide (поступает в листья) from the surrounding atmosphere.

4. Water and carbon dioxide are (исходные вещества) taking part in the photosynthesis.

5. Some sugar (окисляется) in the plant.

6. Carbon dioxide (растворяется) in the water of cell.

7. (В естественных условиях) the energy of photosynthesis is sunlight.

8. (Лучистая энергия) penetrates the water to the depth of deep-sea (водорослей).

9. (Степень насыщения тканей растения) may modify the rate of photosynthesis.

10. In the morning the stomata are opened and photosynthesis (достигает максимальной скорости).

11. When plants (начинают вянуть) photosynthesis is decreased.

12. In the evening the rate of photosynthesis decreases (из-за потери воды) from the mesophyll cells.

TRANSLATION: Translate the sentences into English.

Фотосинтез образование живыми растительными клетками органических веществ, таких, как сахара и крахмал, из неорганических - из углекислого газа и воды - с помощью энергии света, поглощаемого пигментами растений. Это процесс производства пищи, от которого зависят все живые существа - растения, животные и человек. У всех наземных растений и у большей части водных в ходе фотосинтеза выделяется кислород. Некоторым организмам, однако, свойственны другие виды фотосинтеза, проходящие без выделения кислорода. Углекислый газ растения получают из атмосферного воздуха, в котором средняя его концентрация составляет 0,03%. Углекислый газ поступает в листья, а кислород выделяется из них через небольшие отверстия в эпидермисе, называемые устьицами. Устьица регулируют и испарение воды листьями. Водные растения добывают все необходимые им питательные вещества из воды, в которой живут.

SPEAKING: Imagine that you are a teacher of biology. Prepare the lecture about photosynthesis for elementary school.