Learning requires that we hang new knowledge on old facts that are already thoroughly filed, sorted, and understood. Sometimes there just isn’t enough. Hooks, boxes, and shelf space, that is. Sometimes we get a flood of new information, with seemingly no place to stuff it. The sock drawers are full, the coat rack is jammed, and there’s stuff all over the floor.
Do a da Vinci. Use the metaphor as a learning tool.
Da Vinci, it’s been said, would look at a problem, and try to make comparisons to something completely different, in an effort to try to understand it. How is a frog like a helicopter? (Mind you, he probably didn’t have the helicopter thing…OH, he DID invent that, didn’t he?) How is a bunch of bananas like a computer? It really knocks down walls, and makes one think in different directions.
A metaphor can be used also to remember something, something that you really have little base knowledge of. I was recently helping my son with his genetics homework, a huge leap in university from a sparse high school exposure.
Let’s do an example. How is genetic material like human nature? How is human behaviour like genetic expression?
Every cell in the human body has a complete library of the body’s genetic information. Different tissue types evolve by only expressing some of that DNA. Mother cells teach daughter cells which parts of the genome to hide.
Gene expression means different proteins are produced. When different genes are expressed, different cells are seen. What you see are the proteins. All the genetic stuff is hidden in the nuclei. You see a strand of hair, it’s hair because of the proteins produced.
Stem cells are called stem cells because all of their genome is naked, hanging out there and can produce anything. They are all identical. One stem cell can specialize (ie stop being a stem cell, and get all plugged up like all the other cells), and produce neuron, blood cell or teeth… (and the reason why stem cell research is the hottest thing…)
chromatin: DNA plus proteins. There’s more protein (basically histones) than DNA in each chromosome.
The nucleosome is the fundamental subunit of chromatin. DNA + Histones. Each
nucleosome is composed of a little less than two turns of DNA ( 50 base pairs…PHOSPHATES ARE NEGATIVELY CHARGED) wrapped around a set of eight proteins called histones, which are known as a histone octamer (HAS A POSITIVE CHARGE). Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4.
“Chromatin remodelling,” is unwinding, and rewinding of the DNA. This occurs with Transcription Factors, activator proteins, and enhancer sites.
To unwind DNA, one needs to weaken the positive charge on the histones. You do this by acetylating the lysine AA’s. HAT (histone acetyl transferase) is the enzyme that does this.
Other techniques to weaken the positive charge are methylation of lysine, arginine, and phosphorylation of serine and theonine AAs.
Histone DE acetylase increases the positive charge again and winds the chromatin back up. (by taking the acetyl groups off).
There are core promoters, that transcription factors bind to, enhancer regions upstream from the promoter, as well as “silencer” regions, binding transcriptional repressors.
Eukaryotic genes are in a default, “off” position. Even if unbound, even if transcription factors are bound on the promoter, methylation can inhibit transcription.
So let’s walk through this metaphor as a learning tool idea:
Every human being is born full of potential behaviours. Almost a, “stem cell.”
As one grows up in the world, and engages with the environment, certain core beliefs are made. If the baby cries, and mom comes with milk, something is learned. Something is learned about crying, about hunger pains, about mom, about milk. Very early on, baby learns (hopefully), that mom is there. That mom protects, that mom comforts. The world, although full of bright lights and new sounds, becomes a safe place.
When engaging the world, when baby bumps into the big outside, when little Johnny gets his milk money taken away by the big bruiser, core beliefs bump into new clashing information. Thoughts roll off these core beliefs, evoke emotions, which then produce behaviours.
DNA/ core beliefs> Chromatin remodelling/ thoughts> Transcription/ emotions> Proteins/ behaviours.
The thing you see on planet Earth is behaviour. You don’t see anything else, core beliefs through emotions. In DNA expression, all you really see are the proteins produced, the cellular structures. Examining the proteins lets you infer things about the genetics. Examining behaviour lets you infer things about core beliefs.
In every little Johnny’s life, there are factors that affect his course along the way: Transcription factors, activator proteins, enhancer sites. What would correlate? There are core promoters that transcription factors bind to, enhancer regions upstream from the promoter, as well as “silencer” regions, binding transcriptional repressors.
How about eukaryotes are in the default, “Off” position? What correlates with that? Histones…are your behaviours bound up properly… or inappropriately?
Maybe a clunky example… but you get me?
The metaphor as a learning tool. Everything can be broken down to its most essential components, and compared to something else!