"Photosynthesis absorbs carbon dioxide and releases oxygen" Carbon-oxygen balance in green plants and biosphere PPT courseware 2

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"Photosynthesis absorbs carbon dioxide and releases oxygen" Carbon-oxygen balance in green plants and biosphere PPT courseware 2

Review: Green plants make organic matter through photosynthesis

Green leaves create organic matter under light

1. Dark treatment: transport away and exhaust the starch in the leaves

2. Select leaves to shade: Set up a controlled experiment, the part exposed to light is the experimental group, and the part shielded from light is the control group.

3. Alcohol decolorization

4. Iodine solution dyeing: Starch turns blue when exposed to iodine, the part exposed to light turns blue, and the light-shielded part does not change color (yellow-white)

Photosynthesis: place--chloroplast, condition--light, product--starch.

The role of organic matter

1.Construct plant body

2. Nurturing other organisms in the biosphere (through food chains and food webs)

Helmont's explanation:

1. Willow trees absorb a small amount of inorganic salts in the soil

2. Willow trees also absorb a lot of water

Helmont's conclusion: water is the raw material for the synthesis of organic matter in willow trees

1. Photosynthesis uses carbon dioxide as raw material

Conclusion of Priestley's experiment: Plants can renew air that has become turbid due to burning candles and breathing of mice

1. Put a lit candle, a living mouse and a living plant into a sealed container respectively. Why does the candle go out? Why do mice and plants die?

Why can candles continue to burn and mice continue to survive after adding plants?

Plant photosynthesis releases oxygen and absorbs carbon dioxide

group discussion:

1. What should be chosen as the variable for this experiment?

2. In addition to this variable, what should be the other conditions?

3. How to design a control group? Tip: Sodium hydroxide solution can absorb carbon dioxide in the air. (You can use a little 25% sodium hydroxide solution to absorb the carbon dioxide in the air)

2. Photosynthesis can also produce oxygen

Discussion and exchange

1. Please describe the production of gas by black algae immersed in water under light conditions.

Bubbles appear in the water

2. What kind of experimental phenomenon occurs when a sanitary incense with sparks is inserted into a test tube?

Hygiene incense revives

3. Analyzing the experimental results, what is the experimental conclusion obtained?

Black algae produce oxygen in the presence of light

In addition to organic matter, the products of photosynthesis of green plants also include oxygen.

The meaning of photosynthesis:

1. Meet their own growth, development and reproduction needs.

2. Oxygen and food sources.

3. Maintain the carbon-oxygen balance of the biosphere.

3. Application of photosynthesis in agricultural production

Reasonable dense planting: make full use of light and increase yields

skill training

1. The closer the plant is to the light source, the more bubbles will be generated.

Because bubbles are produced by plants during photosynthesis. The more bubbles, the stronger the photosynthesis. Therefore, it can be concluded that the stronger the light, the stronger the photosynthesis.

2. No bubbles appear.

extracurricular extension

The method of applying carbon dioxide to crops in fields and greenhouses to increase crop yields is called air fertilizer, and carbon dioxide is called "aerial fertilizer."

Specific operation method

⑴ Apply more organic fertilizer;

⑵ Directly spray carbon dioxide stored in cylinders;

(3) Light the briquette stove.

practice

1. When performing photosynthesis, the external conditions that plants do not need are ( )

A． carbon dioxide b. water c. High temperature D. Light

2. The essence of plant photosynthesis is ( )

A． Synthesize organic matter to release energy

B． Synthesize organic matter and store energy

C. Decompose organic matter and store energy

D. Decompose organic matter and release energy

3. To ensure that urban residents can get fresh oxygen every day, measures that can be taken are ( )

A． Build more high-rise buildings and live in high-rise buildings B. beautify environment

C. Expand the living area D. Plant more lawns and more trees

4. Which of the following is not the meaning of photosynthesis ( )

A. Provide nutrients and food sources for animals, plants and people

B. Provide energy sources for animals, plants and people

C. Provide oxygen sources for animals, plants and people to breathe

D. Provide a source of carbon dioxide for animals, plants and people to breathe.

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For more information about the PPT courseware "Carbon-Oxygen Balance in Green Plants and the Biosphere, Photosynthesis Absorbs Carbon Dioxide and Releases Oxygen", please click the Carbon-Oxygen Balance in Green Plants and the Biosphere ppt Photosynthesis Absorbs Carbon Dioxide and Releases Oxygen ppt tag.

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Update Time: 2024-09-22

This template belongs to biology courseware People's Education Edition seventh grade biology volume 1 industry PPT template

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