The RNA origin of life
RNA may have been the origin of life on Earth. Go on a whirlwind tour of RNA’s evolving role through billions of years of evolutionary history. You can play the virtual RNA game at NOVA Labs. Created by NOVA.
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- @3:02it says to play the RNA game we have to go to pbs.org/Nova/labs. We have to leave the safety of the Khan Academy and adventure out into the wild world to participate? or is there a place on the academy where we can participate? An activity, or excercise, or a walk through on the computer science section maybe? I'd like to be able to do it without having to leave the Khan Academy I've already been through most of the Academy and approve of everything I've seen so far, but have not done the same for other educational websites like pbs for example. Is there already a place to play the game on the Academy? If so would someone share a link? Thanks, T.S.(13 votes)
- Wow! This is cool! I sure hope they bring something like this to the Academy! that would be cool.(6 votes)
- In the RNA world theory, did RNA exist before cells? The timeline thing at2:30appears to show that.(4 votes)
- In this theory, RNA came first. RNA can do everything it needs to do: selfreproduce, catalyze reactions, regulate - all of which it still does today to different degrees.
Since RNA is chemically relatively simple and doesn't have many different structural elements (only its 4 bases and its repeating backbone), it could be produced by natural chemical processes on some kind of matrix (which helps keeping the molecules in place so that they can get larger and larger till RNA happens). Metallic clay in shallow water is a great contender for that matrix.
This is pretty uncontroversial amongst proponents of Abiogenesis, but after that point scholars are divided on what happened next - did DNA come next as more stable storage medium of information (this is most likely since DNA and RNA are closely related chemically and we know for a fact that RNA can handle DNA) or did RNA develop the ability to make proteins (also not impossible since we know for a fact that amino acids can be made by chemical processes not involving life and RNA is today heavily involved in making proteins).
Once you have all three, no matter what comes first after RNA, the next threshold of complexity, the first cell, is a comparatively easy step.(3 votes)
- What came first, the DNA, or the cell?(3 votes)
- That is kind of like the question, the chicken come first or the egg? Some scientists think that the first organisms came from molecules that basically cloned themselves.(1 vote)
- Wouldn't playing the virtual RNA game be a security risk?
Since scientists can look at the RNA models you made?(2 votes)
- Scientists can use the RNA models you made to help them make scientific advancements. This is not a security risk at all.(2 votes)
- But, didn't that single self replicating molecule have to come from somewhere? Even science wouldn't say that "something came from nothing".(1 vote)
- It explains possible sources of the progenitor RNA in the video.
And, while the concept isn't really related to abiogenesis, science does occasionally posit that something can come from nothing.(2 votes)
- So, if RNA is the beginning of life, where did RNA come into existence? And how did it come into existence? What was there to create RNA?(1 vote)
- So, if RNA is the beginning of life, where did RNA come into existence? And how did it come into existence? What was there to create RNA(1 vote)
- The video touches on it briefly at the beginning. Also, this article also touches on it: https://www.khanacademy.org/science/ap-biology/natural-selection/origins-of-life-on-earth/a/rna-world(1 vote)
- Was the primordial soup, a water-based substance?(0 votes)
Where does life come from? This is one of the most important questions humanity has ever posed. And the scientific answer is: we don't entirely know. You might think that cracking DNA's genetic code should have explained life's origins. And it definitely helped----thanks to our understanding of DNA, we can map out the history of evolution all the way back to single celled life. But that's where we're stuck. The problem is, DNA is a great way to store information, but it doesn't do much else----cells rely on other molecules like proteins to replicate, grow, and survive. Proteins, on the other hand, work great as molecular machines to keep cells alive and healthy, but they can't store information or copy themselves----they need DNA for that. So we have a chicken and egg problem. DNA needs proteins to function, and proteins need DNA to exist. So which came first? Which molecule made life possible? Well, there's a third type of molecule that may hold the answer: RNA. Most scientists think that RNA came first, because RNA can do two jobs: store information and perform various functions that keep cells alive. This idea, that RNA came first, is called the RNA world hypothesis. RNA world suggests that billions of years ago, in some primordial soup of molecules, a self-replicating RNA formed. This may have happened in volcanic vents deep on the ocean floor, or perhaps clay clumps brought the necessary chemical building blocks together. Some scientists have even speculated that early RNAs formed on Mars and hitched a ride on an asteroid to our planet. One way or another, self-replicating RNAs emerged, multiplied, and evolved. Over millions of years they developed into a legion of molecular machines. These microscopic proto-life forms blossomed and competed. The best collections of code lived on, and the weaker ones died out. Survival of the fittest was the name of the game. This competition for survival eventually led RNAs to evolve the ability to build strong, stable proteins, which excelled at carrying out complex biological processes. And somewhere along the line, some critical RNAs mutated into the familiar double helix of DNA. DNA became a stable archive of genetic information that stored blueprints for the most successful RNA and protein molecules. Life became more complex over trillions of tiny steps and happy accidents. And all the while, the RNA lineup grew, alongside lengthening genomes of DNA and complex proteins. And it's all still happening----inside your body. RNAs have adapted to become the Swiss army knives of our cells. Today they can slice, dice, catalyze, build, destroy, code, replicate, and transform. A remarkable diversity from the simplest of beginnings: a single, self-replicating RNA molecule.