What is the structure of DNA 4

DNA / DNA structure and structure

In this article we deal with the structure and structure of DNA. We look at what DNA is there for and how it is structured. Corresponding technical terms relating to the topic are also explained. And at the end there are examples of how they can appear in the exam. This article belongs to our field of biology.

First a quick note: DNA and DNA are biologically identical. DNA is simply the English spelling and DNS is the German spelling. The "A" at the end stands for acid, which in German is translated as acid "S". If you need this in more detail, just have a look at the article DNA + DNA difference.

What is the DNA / DNA?

There is DNA in every human being. It contains the genetic information, so in principle it is our blueprint. What hair color we have, our eye color, body size, how (well) our immune system works, what talents (music, math, etc.) we have and much more is determined or at least influenced by DNA. However, if you have bad grades in mathematics, you should not just blame it on your own DNA, but perhaps also question your own laziness. Nevertheless: Our DNA has a certain influence on whether some things are easier or harder for us.

The DNA or DNS is a Macromolecule. Macro stands for large, while molecules are, in a broad sense, two or more atomic particles that are held together by chemical bonds. The building blocks for the macromolecules - i.e. the DNA - are:

  • phosphoric acid (Phosphate residue)
  • sugar Deoxyribose
  • organic Bases

The combination of a base, a phosphate residue and a sugar molecule is known as Nucleotide.


DNA / DNA structure and structure

What is the structure or structure of DNA (deoxyribonucleic acid) or DNA (deoxyribonucleic acid)? To do this, you should first know that there are four different bases:

  • Adenine (A)
  • Thymine (T)
  • Guanine (G)
  • Cytosine (C)

With DNA it is now the case that each Adenine (A) and Thymine (T) as well as Cytosine (C) and Guanine (G) face. Adenine and thymine are always present equally often in DNA. Cytosine and guanine are also present equally often. DNA has two sides, this is known as a double strand. So if you now know, for example, that I have adenine on one side, then it is immediately clear that only one thymine can "dock" on the opposite side. These are connected by Hydrogen bonds. On the respective side, in turn, the "connections" are made by the sugar (deoxyribose) and phosphoric acid residues. All of this as a graphic:

Have you ever climbed a rope ladder in the playground or in the sports hall? Imagine, if someone climbs on it, it would twist itself. Then you end up with the typical idea of ​​DNA. One speaks here of the Watson-Crick model, named after the two discoverers J. Watson and F. Crick, who developed the model for describing DNA as a double helix, which was created in 1953.


Examples of structure / composition of DNA

Let's look at a few more examples that deal with the structure or the structure of DNA and that can also appear in exams / exams.

example 1: When examining a DNA, it was found that 17 percent of adenine is present. How strong are the cytosine, guanine and thymine?

Solution: Adenine and thymine are the same. So if the proportion of adenine is 17 percent, then thymine must also be 17 percent. Together this is 34 percent. That leaves 100 percent - 34 percent = 66 percent left for guanine and cytosine. Since these also occur in the same amount, it is half - 33 percent - for guanine and 33 percent for cytosine.

  • Adenine at 17 percent
  • Thymine with 17 percent
  • 33 percent cytosine
  • 33 percent guanine
  • That makes 100 percent in total.

Example 2: A line is structured as follows: AATTCGGC. What does the strand look like on the other side?

Solution: Adenine and thymine as well as cytosine and guanine face each other. So A and T opposite and C and G opposite.


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