The DNA Quiz has published a few days ago, and now it’s time to see the correct answers. But if you haven’t participated yet, please click on the blue letters and put your basic knowledge of biochemistry to the test. Thank you!
What does DNA stand for?
• Deoxyribonucleic acid
Where is most of the DNA located?
• Cell nucleus and mitochondria
What is DNA made of?
• Building blocks called nucleotides
How do DNA bases pair up with each other?
• A with T and C with G
What type of bonds hold two strands of DNA together?
• Hydrogen bond
What is the most important property of DNA?
• It can make copies of itself
What does DNA look like?
• A ladder twisted into a spiral
Results: Half of the participants have answered all questions correctly, which is quite amazing! 44 percent got just one incorrect answer, and that’s still great. Only 6 percent missclicked twice, but it’s not so bad after all.
Take a quick look at the chart below, and we are ready to move on!
Now I can’t possibly cover the whole subject in one post, but I will put out some basics and add something interesting and important for you to know about DNA.
What is DNA?
DNA is short for deoxyribonucleic acid, which is a polymer molecule that can be stretched up to 2 meters. Polymers are large molecules that are built up by repeatedly linking together smaller molecules, called monomers. In this case, monomers are nucleotides (adenosine, thymidine, guanosine, and cytidine).
Every nucleotide can be divided into three independent molecules:
- nucleobase (adenine (A), guanine (G), cytosine (C), and thymine (T))
- sugar (deoxyribose)
DNA is the hereditary material in almost every living organism. Nearly every cell in the human body has exactly the same DNA. Most of the DNA is located in the cell nucleus, but a small amount can also be found in the mitochondria, where it is called mitochondrial DNA. The sum total of a single organism’s DNA represents a genome.
The information in DNA is stored as a code made up of the four nucleobases we just mentioned above. Human DNA consists of about 3 billion bases, and more than 98 percent of those are ordered in the same way in all people. The order of these bases is called sequence, and it represents the manual necessary for building and maintaining an organism. It’s similar to the way that letters of the alphabet appear in a certain order to form words and sentences. That’s why some people call it ‘the language of life’.
All the bases are paired up with its complementary partner with the certain help of their fellows – hydrogen atoms – forming hydrogen bonds. Adenine forms two hydrogen bonds with thymine, while guanine forms three with cytosine.
Besides the hydrogen-bond type relationships, nucleobases are also connected to sugar molecules via N-glycosidic bonds, making nucleotides. Furthermore, phosphodiester bonds in DNA polymers connect the 5’ carbon of one nucleotide to the 3’ carbon of another nucleotide forming a chain. When you put two complementary chains together and connect it with a bunch of hydrogen bonds, you get one DNA molecule.
You are probably wondering by now, why isn’t there an -OH group attached to the 2nd carbon in (deoxy)ribose in DNA, just like there is one in RNA?
The answer is quite simple. DNA is such an important molecule so it must be protected from further reactions and decomposition. When the 2′ hydroxyl is absent in deoxyribose, the sugar molecule is less likely to get involved in chemical reactions, so DNA avoids being broken down.
The main abilities of DNA are replication, repair, and recombination.
- DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules. Replication is an essential process because, whenever a cell divides, the two new daughter cells must contain the same DNA as the parent cell. (The image down below)
- DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules, better known as mutations.
- DNA recombination is the exchange of DNA strands to produce new nucleotide sequence arrangements. Recombination occurs typically, though not exclusively, between regions of a similar sequence by breaking and rejoining DNA segments, and is essential for generating genetic diversity and for maintaining genome integrity.
I hope you enjoyed this text, because if you did you’re gonna enjoy the next few as well. I will try to dive deep into DNA science, so you can expect more content related to genetics, proteins, etc… But don’t worry! It will be both fun and educational, as always.
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