Any science tutor video can show you the basics of biochemistry. But I think it's more fun to actually do something hands-on. As you watch this video, think like a science tutor and try to answer the questions posed at the end.
(Spoiler alert! The rest of the text that follows after this science tutor video will give you the answers to the biology questions that are posted in the video.)
Did you get the secret behind anthocyanin? Anthocyanin is a pigment that you'll find in red cabbage. This pigment gives the cabbage its reddish purple color. But that's not all.
Anthocyanin is a natural indicator of the pH of a substance. When it comes in contact with something acidic, it turns red. When in contact with anything basic, anthocyanin turns blue.
I'll post a science tutor video about pH, acids, and bases next week.
Anyway, if you're wondering about the final question in the video, here's the simple answer. The plasma membrane does many things, but one of its functions is to create spaces or vessels where chemical reactions can take place without interference. Imagine the mess I would have made if I just mixed anthocyanin, baking soda, hot sauce, etc. into one container! They would take away my science tutor license and ban me from the lab for sure!
Instead, each chemical process had a separate cup. In a regular chemistry lab, you would probably use test tubes or beakers. Inside of a eukaryotic cell, you would have organelles, and folds of membrane inside the organelles, down to thylakoids or the many tunnels of the endoplasmic reticulum.
As a science tutor, I want you to always try to connect what you learn to something you already know about. In this case, you can think of many chemical reactions being assisted by the presence of membranes. (In the case of prokaryotic cells, the entire cell would be a container of sorts. Many chemical reactions, especially related to metabolism, take place attached to the inner side of the cell membrane.)
If you want to see a science tutor video that gives some detail about the cell membrane, try this one: