Protein : Pengendapan oleh Logam, Uji Biuret, dan Uji PbS

Summary

In this video, the host introduces a practical science experiment focused on protein analysis. The session covers various tests including protein precipitation using different metal salts like AgNO3, HgCl2, and Pb acetate, followed by tests with albumin, casein, and gelatin. The experiment involves adding reagents, observing color changes, and heating samples to analyze the reactions. Viewers are encouraged to engage by guessing the reasons behind the observed changes. The video concludes with a reminder to like and share, offering an insightful and interactive experience for those interested in practical laboratory experiments and science.

Takeaways

• 😀 The video introduces a science laboratory practical session focused on protein testing.
• 😀 Viewers are reminded to subscribe and turn on notifications to stay updated with more educational content.
• 😀 The first experiment involves testing protein precipitation using different metal solutions, including AgNO3, HgCl2, and Pb acetate.
• 😀 For the protein test, albumin is used, with 5 drops of each metal solution added to separate test tubes.
• 😀 The reaction is observed after shaking the test tubes, where precipitation forms, showing the interaction between proteins and metals.
• 😀 The second experiment tests three proteins—albumin, casein, and gelatin—by adding NaOH and CuSO4 to each.
• 😀 A color change occurs after mixing NaOH and CuSO4 with the protein samples, prompting a discussion on why this happens.
• 😀 If no visible reaction occurs, up to 10 additional drops of NaOH are added to encourage further changes.
• 😀 The third experiment involves heating protein samples in a water bath after adding NaOH and Pb acetate, at a temperature of 70°C.
• 😀 The video ends with a question about the cause of the color change in albumin after heating, inviting viewers to share their thoughts in the comments.

Q & A

What is the focus of the practical experiment discussed in the video?

The practical experiment focuses on testing the precipitation of proteins using various chemical reagents.

Which chemicals were used in the first part of the experiment for protein precipitation?

The chemicals used in the first part of the experiment for protein precipitation were silver nitrate (AgNO3), mercury chloride (HgCl2), and lead acetate (Pb(CH3COO)2).

What is the first step in the experiment for protein precipitation?

The first step is to measure 3 milliliters of albumin (egg white) and place it into a test tube.

How do the researchers test for protein precipitation in the first experiment?

The researchers add five drops of each reagent (AgNO3, HgCl2, and Pb(CH3COO)2) to separate test tubes containing albumin and then shake them to observe any precipitation.

What did the researchers observe after adding the reagents to the albumin?

They observed precipitation occurring in the test tubes, indicating that the proteins reacted with the metal reagents.

What proteins were tested in the second part of the experiment?

In the second part of the experiment, the proteins tested were albumin, casein, and gelatin.

What was added to the protein solutions in the second experiment?

In the second experiment, NaOH (sodium hydroxide) and CuSO4 (copper sulfate) were added to the protein solutions.

What was the purpose of adding NaOH and CuSO4 in the second part of the experiment?

The purpose of adding NaOH and CuSO4 was to test for changes in the protein solutions and observe any color changes or reactions.

What was the result after adding NaOH and CuSO4 to the protein solutions?

After adding NaOH and CuSO4, the protein solutions changed color, which the researchers noted and asked viewers to comment on the reason for the color change.

What was the purpose of heating the samples in the third part of the experiment?

The purpose of heating the samples in the third part of the experiment was to observe any changes in the proteins, especially albumin, when exposed to heat at 70°C.

What was observed in the third experiment after heating the samples?

After heating the samples, it was observed that albumin turned darker, indicating a chemical change possibly due to protein denaturation.

How did the video encourage engagement from the viewers?

The video encouraged engagement by asking viewers to comment on the reasons behind the observed color changes and to share the video with others.