Biology Answers: How do enzymes work?

Post your biology questions and biology answers here. That's what this site is for.

Someone asked me how it is possible specifically for enzymes to lower the activation energy of a chemical reaction. It came up with digestive enzymes that split proteins.

I heard a good analogy a few years ago, so I decided to share it in this week's biology answer video. I hope this is useful for you:

The key ring analogy is a good way to explain what happens when an enzyme helps to break up a chemical bond. Normally it would take a prohibitive amount of energy to remove the key. Essentially you'd need an acetylene torch or some other device to blast open the ring.

However, when the key ring is gripped by your fingers, it is like it has formed a temporary hydrogen bond with the enzyme (your fingers). This bond causes the enzyme to change shape, as your fingers move to open the ring.

Then it is easy to remove the key. After this, the key ring snaps shut as enzyme, molecule, and every other part of the system return to their stable, "ready" state.

Biology answers to most questions can be found by looking for an analogy for something. You often hear biology tutors talking about the cell as a city. The nucleus is city hall, the ribosomes are construction workers, and so on.

The "cell as city" analogy is especially useful for biology answers, because it encompasses a lot of possibilities, all of which are closely tied in with the notions of the cell, its organelles, their structures and their functions.

Lately I have not been able to post as often as I would like to, but I'll keep on posting  biology answers as long as my readers are asking biology questions.

Study hard. You're almost done for the year.

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