@Parker Our litmus test for additions to cards is “will this additional info be necessary for me to get a question right?”; while this added information is correct, for the purposes of the MCAT, it’s beyond what testers would need. So, for the sake of keeping things concise, we’ll keep it to the more generalized concept “Vesicles move in retrograde motion.” I will close out this suggestion but feel free to re-submit or message me with any concerns!
The general statement that “vesicles move in retrograde motion” is grossly incorrect. How do any vesicles undergo exocytosis if they only move in a retrograde (toward the “middle” of the cell) direction? How do the trans-golgi vesicles with transmembrane bound proteins get to the cell membrane? How do neurotransmitters in vesicles get exocytosed into the synaptic cleft? Vesicles must have anterograde transport. What direction the vesicle moves is mediated by what proteins coat the vesicle, as described originally.
If the COP and clathrin proteins are too in depth for this card, that’s ok to leave out. But simply saying vesicles move only in a retrograde direction is wrong and should also be taken out.
Though it does seem like the COP proteins are testable. https://www.reddit.com/r/Mcat/comments/btupvr/aamc_sample_bb_4/
Looking at the passage, COP proteins are defined & their relation to Arf1 was explained. It’s one of those concepts that is associated with expected MCAT knowledge, which is why it turns up in a passage, but will itself be explained in passages. The only external concept needed for the question you hyperlinked would be where retrograde transport starts & ends.
It looks like " Vesicles move in retrograde motion" was mentioned in reference to the retrograde COPI vesicles seen in the left image in Extra. Although, to fit in context with the other text in Extra, I’ve edited this to “Vesicles move in anterograde motion for exocytosis” & accepted this change via another suggestion. If you have any other thoughts to add, feel free to reply & we can discuss them
That works great! My main concern was only mentioning that vesicles move retrograde without the anterograde.