98th Percentile Scorer Analyzes an MCAT Biochem Passage

[@i123456987654]

I love this video because the questions aren’t blurry and I can actually see and read the questions...thank you for zooming in!

[@ae3730]

I love this, very helpful & love the logic line you followed! More of these type of videos please.

[@Shemmassian]

Stay tuned! We've got more coming :)

[@lalahollyland]

One thing I've notices about these videos and all MCAT videos on youtube is there are a lot of ways you can go about solving science questions. But this is by far the best method. Instead of freaking out and trying to understand the entire passage I was able to easily and efficiently solve this passage and was able to understand the process and what it was asking as well. I will def be trying this on my upcoming practice exams. Thank you for the tip!

[@Shemmassian]

You're welcome! Glad you're finding these strategies valuable.

[@johnnyace1300]

you were so proud of yourself when you thought of motif and I must say a very apt usage of the word indeed. keeping track IS so difficult because I just find that it rarely comes up that your blatantly asked to remember but rather to extrapolate from that.

[@claram5894]

These are such awesome videos!! Please keep posting these!

[@Shemmassian]

Thank you! Will do!

[@felixantwi-mensah5197]

incredibly helpful, thank you brother

[@Shemmassian]

You're welcome!

[@janeishab7883]

This is so helpful!! I've really been struggling with how to breakdown the passage to answer the question. I feel like I never know what the question is trying to ask.

[@Shemmassian]

Glad it's helping you approach passages more effectively!

[@MrDanonduty]

This video is a lifesaver! Thank you so much, the logic you provided for interpreting the passage and answer choices is amazing! Would you recommend applying the same method to all other mcat sections?

[@Shemmassian]

You're welcome! And yes, many of the strategies apply across sections.

[@omidmoneeb]

Really useful thank you.

[@Shemmassian]

You're welcome, Omid!

[@financefitness6041]

Do you guys provide a service where passages like this can be accessed online and the passage can be underlined/highlighted by the student practicing? If so, I would be happy to purchase this service because I would love to get closer to mimicking the real exam

[@techas2025]

For question 5, I'm confused on why B is correct. The sec59-1Δ cell line was not transformed with YEP352, and it has (statistically) significantly more PE and PI than its transformed counterpart. Shouldn't surviving sec59-1Δ cells (i.e. sec59-1Δ +YEP352-SEC59 cells) have less PE and PI than its not-transformed counterpart, thus making choice B incorrect? Also, for choice D, doesn't it take some amount of time, however brief, for the effect of a gene in a plasmid to take effect in a bacterium? (due to the short amount of time needed to transcribe the gene, etc.)

[@Shemmassian]

This is an excellent set of questions! Regarding your first comment: This question and its answer choices make no mention of knocking out the sec59 gene (i.e. the sec59-1∆ cell line). It is thus much more reasonable to assume that the untransformed cells of answer choices A and B are WT. So, the question is actually asking for a comparison between the WT + YEP352 line (i.e. cells that already have a functional sec59 gene + the YEP352 vector, which encodes another copy of the sec 59 gene + ampicillin resistance) and the WT line. Figure 4 shows that there is no significant difference between WT and WT + YEP352 cells (two leftmost bars of each four bar set) for expression of any of the various phospholipids. But yes, sec59-1Δ +YEP352-SEC59 cells definitely should have less PE and PI than non-transformed counterparts according to the results of Figure 4 like you suggest (comparing the two rightmost bars for each phospholipid in Figure 4). This just wasn't what the question was asking. It seems like you’ve got the right intuition for finding ways to support and rule out answer choices, though! When you're looking for answers based on figures, the two most common correct answers are either an answer supported by statistical significance OR an answer that says two samples being compared are not different when there is no statistically significant difference between the two aforementioned samples. Regarding your second comment: Yes, it absolutely takes some time for the gene(s) in a plasmid to take effect in a bacterium due to the time needed to transcribe and translate (+ etc.) the gene. The question saying “YEP-352 transformed bacterial colony” implies that the bacteria have already taken up the plasmid and are expressing the plasmid genes. So, cells should already have resistance once the colony has been successfully transformed. This is a tricky answer to rule out for sure, but in order to select this as a correct answer, I would have needed something in the question like, “Researchers add the YEP-352 vector to several bacterial colonies and then add ampicillin to separate colonies at t = 0, 5, 20 ... mins. What should they expect to observe?” I would expect that in this case, resistance would be very low in the 0 min treated colony and then increase as colonies are given more time for transformation to occur. If you have any more questions about bacterial transformation, here is a great in-depth resource we offer: www.shemmassianconsulting.com/blog/biochemistry-techniques-mcat (see Part 6!). I hope this helps!

[@FiggitClips]

blud looks like he is being held at gunpoint

[@i123456987654]

Will we be allowed the periodic table of elements for the MCAT?

[@moncler5691]

Absolutely

[@iminaemokpae3334]

For question 5: Would A be correct if there was a significant difference shown between WT and WT+YEP352 in figure 4?

[@gabe3882]

Did you worship the whale to get a great score?