Protein-rich brain food

In this week’s lecture there was a lot of talk about the quizzes. We thought that the quiz itself was fine as we had read the relevant chapters mindfully. However, this caused boredom during the lecture, as we were already well acquainted with the topics of the first part.

Something that we covered during the lecture that was the structure of membrane proteins. During our reading, we were reminded of the fact that ion channels have quaternary structure. This means that they consist of multiple subunits, despite ion channels acting as just one unit.

Especially interesting function of ion channels was the closing mechanisms of the sodium channel. We did not expect a “blob” to be hanging on the protein, which would work as a literal plug. This is also despite another closing mechanism, which takes over as the resting membrane potential is reestablished.

Before this lecture we thought that the proteins would levitate on the membrane the same way that single phospholipids do. However, during this lecture we learned that they are woven into the membrane with the polypeptide chain going back and forth through the membrane. Fully understanding what was going on with the diagram required some further reading and pondering though.

In the past we have often encountered -70 mV as the resting membrane potential. Thereby, we wonder if the -65 mV stated on the course material is a more precise value, or this difference is due to different experimental results?

Lastly, the picture of measuring action potential with an oscilloscope reminded us of this video of pioneering research on giant squid axons:  https://www.youtube.com/watch?v=CXCGqwdtJ78