"The Essence of Plant Photosynthesis" PPT Courseware

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"The Essence of Plant Photosynthesis" PPT Courseware

Part One: Introduction of New Course

As the saying goes: People are like iron, and rice is like steel. If you don't eat one meal, you will be hungry.

Green plants require certain nutrients every day. They can not only supply themselves with food, but also produce food for other creatures on the earth and feed us.

Guess: What are the main ingredients in these foods?

Starch turns blue with iodine

Where does starch come from?

green plants

The organic matter (such as starch, etc.) produced by green plants feeds almost all living things on the earth.

The essence of plant photosynthesis PPT, part 2: photosynthesis produces starch

Explore how green leaves make starch under light

Purpose: To illustrate that green leaves can produce starch under light.

How to verify that green leaves are producing starch?

Does the process of making starch in green leaves require sunlight? how to prove?

Design comparison:

Can you design a comparison between plants with and without light to prove that photosynthesis requires light?

Find loopholes:

Xiao Ming directly picked a leaf from the tree, used alcohol to remove the green color, added iodine solution dropwise, and found that the leaf turned blue. Xiao Ming said: This shows that the leaves produce starch under light.

Discussion and Thoughts:

1. Based on the phenomena observed in the experiment, what is the experimental conclusion you draw?

Answer: When the leaves of green plants perform photosynthesis under light, they can produce starch.

1 Starch is an organic substance that stores a large amount of energy.

2 The seeds of plants such as corn, wheat and rice contain large amounts of starch.

Class exercises:

1. In the experiment of "exploring the relationship between sunlight and organic matter" using vegetables, the correct order of experiments is ＿＿＿＿＿＿

(1) Add iodine solution dropwise to the leaves

(2) Shade part of the leaves

(3) Rinse with clean water

(4) Observe color reaction

(5) Decolorize with alcohol

(6) Dark treatment for one day and night

2. Flowers and plants grown at home will die if left in a dark place for a long time. Can you tell me why?

Light is the condition for green plants to produce organic matter. If the plant does not receive light for a long time, it will not be able to synthesize the organic matter necessary for its own life activities, so it will die.

3. Take a piece of silver-edged geranium leaf that has been illuminated and remove the leaves.

After staining with iodine solution, the edges did not turn blue, and the other

The part turns blue, and this experiment proves ().

A. Photosynthesis requires light

B. Photosynthesis releases oxygen

C. Photosynthesis requires chloroplasts

D.Photosynthesis requires carbon dioxide.

The essence of plant photosynthesis PPT, the third part: photosynthesis produces oxygen

Explore how green leaves produce oxygen when exposed to light

Purpose: Explain that green leaves can produce oxygen when exposed to light

Materials and tools:

Glass funnel, beaker, test tube, hornwort, matches, water

Methods and steps:

1. Take the hornwort and put it in a beaker filled with water, and then turn the glass funnel back. Fasten a test tube filled with water to the neck of the funnel.

2. Place the device under sunlight, and the hornwort will continuously release small bubbles.

3. After the water in the test tube drops to a certain height, remove and invert the test tube so that the mouth of the test tube faces upward.

4. Use a matchstick with sparks to quickly insert into the test tube and observe what happens.

A matchstick with a spark can re-ignite. produced oxygen

The essence of plant photosynthesis PPT, Part 4: Photosynthesis requires carbon dioxide

Explore how green leaves absorb carbon dioxide under light

Purpose: Explain that green leaves can absorb carbon dioxide under light

Experimental guidance

1 Use recommended textbooks to form two sets of experimental devices

2 Add sodium bicarbonate solution to beaker a

Record the same amount of tap water in beaker B

3 Put the two sets of devices under the light

4 Observe the changes that occur in the funnel and test tube. Think about it, what substances are produced? How to prove it?

The essence of plant photosynthesis PPT, Part 5: Answers to questions

Why should geraniums be kept in the dark for 1 day and night?

Answer: The purpose of placing potted geraniums in a dark place before the experiment is to allow the geraniums to transport and consume all the starch in the leaves in the dark. In this way, the starch tested with iodine solution in the experiment can only be produced by the leaves during the experiment. It is impossible that the leaves were stored before the experiment.

Why cover part of the leaves with black paper?

Answer: It is for a control experiment to see if starch can be produced in both parts that are illuminated and parts that are not illuminated.

Why put the leaves in alcohol and heat them over water? What's the purpose of this?

Answer: Because not only does alcohol evaporate too quickly, causing waste, but the effect of dissolving chlorophyll is not very good, and it is especially dangerous to ignite alcohol. This step is to dissolve the chlorophyll in the leaves in alcohol to decolorize it, making it easier to identify and observe the color of starch.

Keywords: Jiangsu Education Edition seventh grade biology PPT courseware free download, PPT download, .PPT format;

For more information about the PPT courseware "Photosynthesis and Respiration of Green Plants and the Essence of Plant Photosynthesis", please click the "Photosynthesis and Respiration of Green Plants ppt Essence of Plant Photosynthesis ppt" tag.

"The Essence of Plant Photosynthesis" PPT:

"The Essence of Plant Photosynthesis" PPT Part One Content: Situation Introduction Green plants are giant natural factories that produce organic matter. They can use carbon dioxide and water as raw materials to produce huge amounts of organic matter under light conditions, feeding almost all the things on the earth. .

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Update Time: 2024-09-08

This template belongs to biology courseware Jiangsu Education Edition Seventh Grade Biology Volume 1 industry PPT template

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