Praktikum Fotosintesis - Uji Sachs

Summary

This video demonstrates a photosynthesis experiment aimed at proving that photosynthesis produces starch and requires light. The process involves using a leaf exposed to sunlight, covering some parts with aluminum foil to block sunlight, and then treating the leaf with alcohol to remove chlorophyll. After adding iodine, the leaf turns blue where photosynthesis occurred, indicating starch production. The section covered by foil remains colorless, proving no starch was produced there due to lack of light. This experiment effectively demonstrates the key concepts of photosynthesis, making it a valuable learning tool.

Takeaways

• 😀 Photosynthesis is the process by which plants make food using carbon dioxide, water, and sunlight, producing carbohydrates and oxygen.
• 😀 The aim of the experiment is to prove that photosynthesis produces starch and that it requires light.
• 😀 A set of heating tools is required for the experiment, including a Bunsen burner, asbestos gauze, test tubes, and a beaker.
• 😀 Materials needed for the experiment include a plant leaf, mud solution, 70% alcohol, and aluminum foil or grenjeng paper.
• 😀 The leaf should be covered with aluminum foil or grenjeng paper for a few days before the experiment to block sunlight from reaching certain areas.
• 😀 The leaf is heated in hot water to kill the leaf cells, which helps prepare it for the next steps in the experiment.
• 😀 The leaf is then placed in a beaker with 70% alcohol and heated until the chlorophyll is dissolved, turning the leaf colorless.
• 😀 Afterward, the leaf is dripped with Lugol solution or iodine, which turns the part exposed to sunlight blackish blue, indicating the presence of starch.
• 😀 The part of the leaf covered by aluminum foil does not show starch and turns pale white, proving no photosynthesis occurred there due to the lack of sunlight.
• 😀 The experiment demonstrates that photosynthesis not only produces starch but also requires light, as seen from the contrasting results between the covered and uncovered leaf parts.

Q & A

What is photosynthesis?

Photosynthesis is the process by which plants make food using carbon dioxide, water, and sunlight energy, producing carbohydrates and oxygen.

What are the two main aims of this photosynthesis experiment?

The two main aims are to prove that photosynthesis produces starch and to prove that photosynthesis requires light.

What tools are needed for the photosynthesis experiment?

The tools needed include a bunsen lamp, three-legged stand, asbestos gauze, dropper, test tube, beaker, petri dish, and tweezers.

What materials are required for the photosynthesis experiment?

The materials required are a plant leaf, mud solution, spirits, 70% alcohol, and aluminum foil or grenjeng paper.

Why is aluminum foil or grenjeng paper used in this experiment?

Aluminum foil or grenjeng paper is used to cover some parts of the leaf, blocking sunlight, to demonstrate that light is necessary for photosynthesis.

What is the purpose of heating the leaf in hot water during the experiment?

Heating the leaf in hot water wilts it, which helps kill the leaf cells before proceeding to the next steps of the experiment.

Why is the leaf submerged in 70% alcohol after being wilted?

The leaf is placed in 70% alcohol to dissolve the chlorophyll, which is necessary for observing the changes in starch content during the experiment.

What is the role of Lugol's solution in this experiment?

Lugol's solution, or iodine, is used to detect the presence of starch in the leaf. The areas that have undergone photosynthesis turn blue-black when iodine is applied.

What happens when iodine is applied to the leaf after the experiment?

After applying iodine, the part of the leaf exposed to light turns blue-black, indicating the presence of starch. The part covered by aluminum foil remains pale, showing no starch, proving that sunlight is required for photosynthesis.

What does the experiment prove about the relationship between light and photosynthesis?

The experiment proves that photosynthesis requires light, as only the part of the leaf exposed to light produces starch, while the covered part does not.