How to memorize all 20 amino acids fast using the science of learning
(5 minute read)
Pre-med students often need to memorize all 20 amino acids. Here’s a faster way using science-backed methods:
Why free recall beats flashcards for amino acids
Upon looking at the image above, the first instinct for many is to make flashcards. And they usually work well enough.
But there are several problems with flashcards, and I propose that free recall—simply writing everything you can remember about every amino acid without any help—solves all of them and makes your life a lot easier.
Problem #1: weak associations make amino acids hard to remember
Traditional flashcards create weak, cue-dependent associations. For example:
Front: "Alanine side chain type"
Back: "nonpolar / hydrophobic"
Here, recall only occurs when the exact cue is presented, producing shallow, recognition-like memory that doesn’t transfer well to new contexts.
Free recall, by contrast, requires retrieving information without cues. Actively recalling all amino acids and their properties strengthens connections between concepts independently of prompts.
Cue-independent knowledge is more:
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Accessible: Information retrieved through free recall is more readily accessible when needed [1].
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Durable: Memories formed through free recall tend to be retained longer, requiring less frequent review [2].
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Transferable: Knowledge acquired via free recall is more easily applied across various contexts, such as curveball exam questions [3].
Problem #2: the "big picture" of amino acids is fragmented by flashcards
Actively retrieving topics naturally organizes related items [1], giving you the big picture, rather than a collection of fragile associations. With this organized schema, you essentially have multi-dimensional access to every possible angle of the same knowledge, further improving your ability to answer curveball questions.
This organization is evidenced by two additional benefits:
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Better learning of future knowledge: Structured schemas act as scaffolds, making related new knowledge easier to acquire [1,2].
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Strengthens existing knowledge: Organizing current knowledge reinforces connections, improving retention of previously learned material [2,3].
Problem #3: takes too long to learn all 20 amino acids with flashcards
With free recall, you simply write or draw everything you know about all 20 amino acids, review what you missed, and repeat until you can recall it all. You can start immediately and finish quickly.
Flashcards, by contrast, require you to:
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Look up each amino acid,
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Create individual cards, and
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Recall only one simple, weak association at a time.
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Revisit the flashcards frequently because the associations aren't durable
Free recall accomplishes everything flashcards do—but more efficiently:
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You recall at a much faster rate.
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You retrieve both the cue and the response, not just the response to a single prompt.
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You form strong, cue-independent associations.
These three advantages compound, making free recall significantly faster and more effective than traditional flashcards.
Downsides of studying amino acids with free recall
Of course: there's always a catch!
#1: Free recall can reinforce incorrect knowledge
Free recall is astoundingly effective, but only if you can recall the knowledge in the first place. So you'll need to review carefully to see what you missed following the free recall.
Fortunately, review is much more effective after free recall. Effortful retrieval puts your brain in “edit mode,” making the relevant neural pathways more plastic and ready to be strengthened [1,2].
If you're hardcore, you can brute force recall and review until you know everything using the free recall gauntlet.
#2: Free recall is hard (to start).
It's not hard while you're doing it: you get into a flow state pretty quickly since it's so cognitively engaging. But it is always a daunting task to start since you're diving into the deep end without any help.
But it's not harder than failing a biochem exam because you didn't know the amino acids as well as you thought.
It's difficulty is exactly the reason free recall is often underestimated: it doesn't feel good so it must not be good. These metacognitive predictions couldn't be further from the truth!
Actual Performance
Metacognitive Predictions
Adapted from Karpicke, J. D., & Blunt, J. R. (2011). Retrieval practice produces more learning than elaborative studying with concept mapping. Science, 331(6018), 772–775. https://doi.org/10.1126/science.1199327
vs.
Free recall vs flashcards: why free recall wins
To summarize, here's everything that free recall does better than cued recall tasks, like flashcards:
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Makes knowledge more accessible in more situations (Carpenter, 2012)
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Makes knowledge more transferable to new tasks (Butler, 2010)
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Makes knowledge more durable, taking longer to forget (Roediger & Karpicke, 2006)
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Strengthens related, unrecalled knowledge (Chan, 2009)
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Strengthens related knowledge to be learned in the future (Storm et al., 2014)
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Makes knowledge plastic, making re-study more effective (Karpicke & Roediger, 2007)
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Prevents suppression of related knowledge through RIF, if done correctly (Anderson et al., 1994; Storm et al., 2008)
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More details surfaced per minute (Tulving & Pearlstone, 1966)
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No setup time (e.g., making flashcards)
That's all to say: it saves you a lot of trouble to just do the work now.
Thank you for reading all the way to the end! I applaud you for taking your future seriously.
I love applying science to learning—and it's thanks to students like you that I continue to do it. If you found it helpful, feel free to check out SAM.
Here's the catch—SAM is hard. If regular studying is yoga, SAM is powerlifting.
Anyone selling you an easy fix isn’t being honest. A core theme in the science of learning is desirable difficulty: your future life only gets easier if you put in the effort now.
For many of us "studying" can be a day-long cycle of half-assing and self-loathing. If you're like me, you'd rather sweat for an hour, feel good about it, and relax the rest of the day.
Why SAM?
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Get 10+ hours back every week. Add a day to your weekend.
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Two-hour read. Lifetime return.
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100% evidence-backed. Practical. Little-known. Perfected over years of testing.
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Zero guesswork. Zero decision fatigue. Know exactly what to do, step-by-step, for any course.
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No more catching up, just stay ahead by default
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Unlock career paths that demand top scores: medicine, law, dentistry, etc.
Whether or not it's your cup of tea, I hope you enjoyed the article.
Happy studying,
-Sam
References:
[1] Roediger, H. L., & Butler, A. C. (2011). The critical role of retrieval practice in long-term retention. Trends in Cognitive Sciences, 15(1), 20–27. https://doi.org/10.1016/j.tics.2010.09.003 [2] Karpicke, J. D., & Roediger, H. L. (2008). The critical importance of retrieval for learning. Science, 319(5865), 966–968. ]https://doi.org/10.1126/science.1152408 [3] Butler, A. C. (2010). Repeated testing produces superior transfer of learning relative to repeated study. Journal of Experimental Psychology: Learning, Memory, and Cognition, 36(5), 1118–1133. https://doi.org/10.1037/a0019902 [4] Carpenter, S. K. (2012). Testing enhances the transfer of learning. Current Directions in Psychological Science, 21(5), 279–283. https://doi.org/10.1177/0963721412452728 [5] Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255. https://doi.org/10.1111/j.1467-9280.2006.01693.x [6] Chan, J. C. K. (2009). Retrieval-induced facilitation: Initially nontested material can benefit from prior testing. Journal of Experimental Psychology: Learning, Memory, and Cognition, 35(5), 1442–1457. https://doi.org/10.1037/a0017067 [7] Storm, B. C., Bjork, R. A., & Bjork, E. L. (2014). The retrieval-induced facilitation effect: Strengthening of related memories through retrieval. Journal of Experimental Psychology: Learning, Memory, and Cognition, 40(3), 857–871. https://doi.org/10.1037/a0035567 [8] Karpicke, J. D., & Roediger, H. L. (2007). Expanding retrieval practice promotes short-term retention, but equally spaced retrieval enhances long-term retention. Journal of Experimental Psychology: Learning, Memory, and Cognition, 33(4), 704–719. https://doi.org/10.1037/0278-7393.33.4.704 [9] Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). Remembering can cause forgetting: Retrieval dynamics in long-term memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20(5), 1063–1087. https://doi.org/10.1037/0278-7393.20.5.1063 [10] Storm, B. C., Bjork, R. A., & Bjork, E. L. (2008). Accelerating the rate of forgetting with retrieval: Retrieval-induced forgetting as a metacognitive tool. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34(2), 449–458. https://doi.org/10.1037/0278-7393.34.2.449 [11] Tulving, E., & Pearlstone, Z. (1966). Availability versus accessibility of information in memory for words. Journal of Verbal Learning and Verbal Behavior, 5(4), 381–391. https://doi.org/10.1016/S0022-5371(66)80048-8 Karpicke, J. D., & Blunt, J. R. (2011). Retrieval practice produces more learning than elaborative studying with concept mapping. Science, 331(6018), 772–775. https://doi.org/10.1126/science.1199327