DNA Repair

in this video, we're going to begin our lesson on DNA repair. And so it turns out that DNA replication is not always a perfect process. And so most of the time, DNA replication works exactly as it's supposed to. But occasionally DNA replication will not work perfectly, and it will create errors, and so base pairing errors can occur during DNA replication. And so, for example, we know that Azour added means are normally supposed to be paired up with teas or thigh means. But if there's a base pairing error that occurs, then this a might be base paired with a C or cytosine instead of being based paired with the T timing like what it's supposed to be. And so these base pairing errors can occur, and these errors occur one out of every 100,000 base pairs, which at first glance might seem like a really low error rate on Lee. One error out of 100,000 base pairs. But it's actually a relatively high error rate, considering that there's a lot of DNA and the DNA replication needs to occur. Often now, unrepaired errors can actually result in permanent mutations, and these permanent mutations in the DNA can actually lead to diseases like cancer, for example, and so down below. In our image in our example image. We're showing you how these DNA errors can kind of resemble typos in a resume. And so in this cartoon that we're showing you down below, this guy over here is coming in for an interview for a job position, and he hands his resume over to the big boss over here. And the boss is reading through the resume. And he says, says here that you're a professional booger and this guy's trying to clear it up. He's like, Oh, I meant Blogger. And so that's a typo that's in the resume, and that is gonna greatly affect this guy's chances of landing this job position. And so mutations These unrepaired errors in the DNA kind of resemble typos and a resume, and so they can actually significantly change the end result off, um, the product that's supposed to be encoded by the DNA And so these unrepaired errors or mutations can lead to diseases like cancer. And so this year concludes our brief introduction to DNA repair, and we'll be able to talk a little bit mawr as we move forward in our course. So I'll see you in our next video

in this video, we're going to briefly introduce DNA proof reading and DNA repair enzymes. And so DNA prelim a race is actually have a proof reading ability. And so this proof reading ability is really just an ability that these DNA prelim races have to find and fix many of the errors or mistakes that might occur during DNA replication. And so the proof reading ability that these DNA prelim races have actually allows them to significantly reduce the error rate from one in 100,000 to just one in 10 billion base pairs, making mutations ah, lot less likely due to mistakes with DNA. Polymerase is, however, they are still possible because one in 10 billion is still possible. Now, other DNA repair enzymes on top of the DNA polymerase proof reading can actually also be involved with helping to correct errors that may not have been fixed by proof reading and so down below in our image. What we're showing you is a little cartoon of a DNA proliferates over here, proof reading the DNA sequence after replication. And so it says, hm. Looks like you made a typo here. And what this proof reading ability allows for is for fixing those errors and mistakes in the DNA. And so again, that will reduce the air rate till just one in 10 billion base pairs, which is significantly lower and makes mutations due to errors and DNA replication, much less likely. And so this year concludes our brief introduction to DNA proof, reading ability and repair enzymes that can also help reduce error rates. And we'll be able to get some practice applying these concepts as we move forward in our course, So I'll see you all in our next video.