How is DNA structured? What are bases? What is a sequence?

Curious about DNA? You're in the right place. In this beginner friendly video, we break down what DNA is, how it's structured, and what it actually does in your body. You'll learn what a DNA sequence is, why it's so important, and how errors, called mutations, can occur during DNA replication. Whether you're a patient, care partner, student, or just curious about genetics, this is your guide to understanding the code of life. Made simple.

We will start by learning what deoxyribonucleic acid, commonly called DNA is and what it does. What is DNA? So DNA is what makes us. It's almost like the recipe, of, in a cookbook. The instructions. It contains all of the information that makes our body function that forms ourselves. So in our body, every cell has DNA that has all of the information on how to make protein, how to function, how to activate, and deactivate things. That is what keeps us alive. And we acquire the DNA, half of it from our mom and half away from our dad, or male or female. And then that's what makes us unique. It has all of the information of how we're going to function.

The DNA is the same in every cell, in one person's body. DNA codes everything that we find in every cell, depending on which organ, depending on which cell in the body. Some regions of the DNA will be active and others will be inactive or closed, and the machinery of the cell knows which portions of the DNA to what we call transcribe, to basically decode and then convert or translate into the rest of the structures of the cell in the body.

Where is DNA located? So the DNA is found in ourselves and our chromosomes. So we have chromosomes in our body and the chromosomes are concentrated DNA. It's very, very concentrated. And then the body has this ability to be able to know how to untangle the DNA whenever it needs to be read and transcribed or read the information or this recipe of what they need to do. And then it gets tangled again so that it can all be concentrated within a cell. DNA is the genetic information that's passed down from parents to their offspring, and it is found in every cell. And it's, found specifically in a compartment of the cell called the nucleus. And how it's arranged is in what we call chromosomes. Because if you were to stretch out DNA, I think it would go on for like miles and miles and miles. So it has to be tightly compacted into the structures we call chromosomes, which each person has 23 pairs of them. And so the DNA is tightly wound around these proteins called histones and arranged in these packages called chromosomes.

DNA bases are the building blocks of DNA, and they make up the genetic code. Let's learn more about these building blocks. So the DNA bases, there’re four different nucleic acids. These are chemical compounds normally found in the body coding information for the cell and for and found in the DNA. So we've got adenine, cytosine, guanine, and thymine. So A, C, G, T and they're arranged in different orders to make a whole bunch of different combinations and a whole bunch of different genes. So two strands of DNA that are arranged in what we call the double helix and one strand has a complementary or matching pair on the other strand. So the A is going to line up with the T. G is going to line up with C on the on the strand as they kind of, follow each other in the helix formation.

What is the structure of DNA? DNA is what we call a double helix, like a double helix ladder. And basically the DNA has certain bases, what we call bases that could be different A, T, G, C. And these four bases have a counterpart. And when they're together, they form this almost like a ladder which we call a double helix. And then that is entwined or twisted If you remember, in the olden days when we had telephones and they had the cord and it would all get tangled, that's exactly what the DNA tends to do. It tangles all up so that it can actually concentrate more in a place.

What is a DNA sequence? A sequence is the order of or arrangement of the different bases. So the four bases, as I mentioned, different combinations, and the sequence is just the arrangement, in that order. And so you can have the sequence of a gene. So one region of the DNA that is responsible for coding a specific protein. Or you can have the entire genomic sequence. So that is every single gene laid out in a specific order Because it's a ladder you might have like A, A, A, A or A, A, T, T or A, T, C, C, depending on what the sequences of those four bases is. What you call a sequence in that sequence is what's going to give us, meaning to or, an order or an indication or an instruction as to what to do or what that information is, When we read a DNA sequence, we usually read just one strand from five prime to three prime. The direction of the strand. The other strand is called the complementary strand and isn't read directly. It's implied because of base pairing.

what is DNA replication and why is it necessary? Every cell has DNA in it, and every cell of what we call eukaryotic organisms are cells having DNA in them exhibit a certain genetic trait. Now DNA, the basic function of a cell, is one to survive and two to reproduce. You know, it's completely programed in them. The cell has a basic intrinsic necessity built in and then to exist and to reproduce. So how does that happen? That often happens, which we may have heard of in our biology class says cell division. When a cell division happens, what really happens is that the DNA or the genetic material which is contained within each cell, it tries to create an exact replica of itself. And then the remaining portion of the cell or the cytoplasm sort of splits and then creates another new cell.

How do mutations occur during DNA replications? So while this happens when the DNA, the existing genetic material, the cell tries to create a self copy of itself, it usually does a very good job. And you know, 100% of that is completely translated. But when that happens there are always some checks and balances intrinsically built within the body that looks for any kind of errors across the DNA material. To give you a visual, the DNA is something like what we call a double helix structure, which means that it has twists and turns and many spokes and builds. But to simplify it, think of a ladder that are two longitudinal verticals, and they're connected by many bonds. And that's exactly how a DNA looks like. So if you want to replicate that ladder into one, there are many proteins that are involved in creating a new ladder. However, you can imagine the ladder is very, very long and you might miss a book or two when during the assembly of the new ladder or the new DNA, if one spoke, goes into, let's say, even one position different, then the message below is completely wrong. And that is what is called as a mutation.

Chromosomes will be the topic of the next lesson in this health tree. University course on basic genetics in cancer tumor biology. If you found this HealthTree University lesson helpful, give us a like and subscribe to our channel. You can also watch the other lessons in this course on our YouTube playlist or on the HealthTree University website.