Course: Cell Biology Part 4: Cell-Cell Interactions
Length: 7 weeks, 4-6 hrs/wk
Instructor: Profs. Rebecca Lamason and Sebastian Lourido
This is the final cell biology course in a four-part series…. How do we know what we know about cells at a molecular level and how can we use that knowledge to design experiments to test hypotheses in cell biology? How do you go from a single cell to trillions of cells working together? And what happens when this amazing collective is confronted with pathogens?
Short version: This was a great way to end the Cell Bio series. While proteins, receptors, and the like are still important, the context is more familiar than inner-cell machinations: the structure of tissues, growth and development of various organs, reactions to pathogens and cancerous changes.
A few years ago, I came across an article by a Bio grad student who was discovering that academic biology wasn’t what he’d become enchanted with via Carl Sagan, Isaac Asimov, and Steven J. Gould. He felt kind of screwed: “[W]hat do you do next when there is nothing you have been trained to do well enough except inspect a single protein or a single gene every day for six years[?]”
Sometimes, deep into some of these biology moocs, I have a glimmer of what he means. When you’re tracing down the result of inhibiting one protein in a pathway of inhibitors and activators, when I’m trying to remember which receptor goes with which ligand, or, at my basic level, whether it’s kinase or phosphatase that removes a phosphate, or, as in the prior course in this series, why actin matters at all, it’s hard to remember how fascinating cells and organisms are, how impossible it seems that bacteria, let alone people, live at all given the complexity necessary to sustain life.
This mooc reminded me. I don’t mean to sounds hyperdramatic, but it was exciting to see bits and pieces from other moocs – anatomy, physiology, pathology, immunology – show up (I love that “Hey, I remember this!” feeling) and to in most cases take a deeper look into how topics within those fields actually work.
The first week was all about tissues. No, not the things you blow your nose into, but bodily tissues. How many kinds of tissues are there, and what’s the difference? What holds our tissues together, how are some anchored to a basement membrane, while others move around? I remember learning about the tight junctions of the blood-brain barrier, and here I not only found out how those junctions are tightened, but where else they exist and why. And I finally found out what’s so interesting about actin and microfilaments.
Week two got into how tissues and even organs replenish themselves over time, and the importance of stem cells in doing so. One of the many mysteries of biology for me has always been, how do we start as one cell, a fertilized egg, and then turn into people with livers and kidneys and brains and skin? I’ve always found embryology mysterious, so it was interesting to get some idea of how cells differentiate. I was surprised at how interesting the intestinal epithelium can be, given how those cells regenerate so often.
Then it was on to death. Apoptosis – programmed cell death – comes up in a lot of bio courses, so it was great to see some of the mechanisms that initiate the process, and those that prevent it from starting in error. Week Four introduced salmonella and listeria, how they differ – and how they don’t – as infective agents.
Week Five introduced the immune system, a timely topic and one pretty familiar to me since I’ve previously done Rice’s three-part immunology series – not to mention the variety of explanations of immunity and how vaccines work dispersed via Twitter and TikTok over the past year, from the professional classroom versions to the goofy-but-accurate metaphors (Seize the Forks!).
The final week gave us a look at cancer at the cellular level. The bit of information that sticks with me is that cancer cells still have features specific to the types of cells from which they developed. This turns out to be useful in figuring out how to treat different cancers. We also saw an overview of what types of changes cells undergo that allow them to not only over-replicate, but move around the body and seed themselves outside the tissue of origin. I’m not particularly interested in cancer, but this really grabbed my attention and made me wonder what else I’ve been missing.
The material followed the typical structure: each week consists of a lecture broken up into several video segments, each followed by a “Test Yourself” quiz that’s graded but allows unlimited tries. A weekly quiz follows five of the lectures. Four of these quizzes are available to auditors; to take all five, and keep access to the course material requires a $99 verification fee.
These quizzes take the form of lab scenarios: you want to test a hypothesis about a protein so what qualities and functions of the protein do you need to keep in mind, and how might you test your hypothesis; or you predict what to expect from an experiment, and explain why something different happened. Often there are graphs representing results and interpretation is required. It’s the best part of MIT’s bio courses: these are not information retrieval questions, you can’t just look up the answers, you have to understand what’s going on. More teachers should pay attention to this, because it’s extremely effective, and a lot more fun than memorizing pathways. And I’m guessing it better represents the experience of a bio major and/or grad student.
As with the other parts of this series, students could submit Mudslips, that is, comments and questions about the parts of the lecture that seemed muddy or unclear. Staff also answered questions on the discussion forums; students often chimed in as well.
There were some signs that COVID had interfered with production. Most MIT Bio moocs use lectures taped in live classroom settings. Here the professors were speaking directly to camera, which has a slightly less connected sense. Prof. Lamason worked in an empty classroom using those amazing movable chalkboards; Prof. Lourido worked from what looked like a narrow office, appearing in a mini-window tucked in the corner of the screen to leave room for notes and diagrams. It seemed like there were fewer animations and diagrams, and more drawings, and the animations that were used weren’t as smoothly incorporated as usual, though that’s just an impression. None of this was disruptive or problematic; it just wasn’t peak MIT presentation. Considering the circumstances, I’m impressed they were able to put together anything at all.
I’d highly recommend this for bionerds. I remember feeling a bit disenchanted after the third part of this series, covering actin and the cytoskeleton. This course perked me back up. It made a very nice finale to an excellent series. I’ve heard they’ll be condensing the first two courses, Transport and Signaling, into one, so next year it will be a three-part series. I’m planning to take it again, this time entering material into Cerego so I have a better chance of remembering it! What can I say, I grow old, and I like it when questions pop up a year after the course has ended. Gives me another “Hey, I remember that!” moment.