Dna what is it

What Is DNA And How Does It Work?

Deoxyribonucleic acid, or DNA, is a molecule containing instructions on how to make a living organism. Its structure and sequence instruct the cell on how to make proteins, which go on to carry out important functions of a cell. Many cells form tissues, many tissues form organs, and all the organs together form a living organism!

If there is one thing that both unites and separates all living organisms in the world, it is DNA.

Plants, animals and bacteria all contain the essential biological molecule known as DNA or deoxyribonucleic acid. DNA contains all the information required to build and maintain living organisms. You can think of it as nature’s very own top-secret instruction manual!

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What is the structure of DNA?

This manual is written in multiple combinations, but limited to just 4 letters : A, T, G and C. Each letter denotes a nitrogenous base: A for adenine, T for thymine, G for guanine and C for cytosine. Every living being has a huge supply of these 4 bases, each of which is attached to a pentose sugar and a phosphate molecule. Together, they are known as a nucleotide. These nucleotides are arranged in two long coiled strands like a hair braid. The bases on the two strands pair up with each other; A with T and G with C, forming base pairs.

Structure of DNA (Photo Credit : Zvitaliy/Shutterstock)

Thus, a DNA molecule is like a ladder that twists like a corkscrew, with the sugar and phosphate acting as the side rails and the base pairs acting as the rungs.

Where do we find DNA?

DNA is an extremely long molecule, so long that if all the DNA in a human was uncoiled and placed end to end, it would stretch 10 billion miles. That would be the same as a round trip to Pluto! However, it is also thousands of times thinner than a strand of hair. Locationally speaking, DNA is found inside the nucleus of each of the body’s cells, tightly packed into packages known as chromosomes.

Packaging of DNA into the cell nucleus (Photo Credit : Designua/Shutterstock)

What does DNA do?

However, to understand exactly how codons are decoded, we need to travel to the HQ.

DNA is stored in the cell ‘HQ’, the nucleus, where various ‘secret agents’ called enzymes get their hands on this important document (DNA). They need the information stored in the DNA to build important machines known as proteins.

Unfortunately, these agents face a difficult hurdle. The raw material (amino acids) and the factory (ribosome) required to build the machines (proteins) are both found outside the HQ (nucleus). That may not initially seem like a problem, as the DNA could simply be taken outside the nucleus, right? However, that’s the problem… since the DNA is such a valuable ‘document’, it cannot leave the HQ!

The differences between mRNA and DNA (Photo Credit : 3Dstock/Shutterstock)

Instead, bits of the information from the DNA are copied into smaller, single-stranded molecules known as messenger ribonucleic acid (mRNA). The mRNA travels out of the HQ and finds its way to the protein factory, which is the ribosome. In the ribosome, the instructions for amino acid attachment encoded on the mRNA are interpreted to form a protein. The amino acids are attached one after the other like beads in a necklace until the process is terminated, as determined by the instruction codes.

Summary of Protein Synthesis (Photo Credit : VectorMine/Shutterstock)

The newly built proteins, with a few changes along the way, go on to make up cells, which in turn form tissues, which then form organs. When combined, all these organs form a living being.

Now, the type of living being formed is entirely dependent upon the sequence and number of the aforementioned DNA bases. The complete instruction manual for human beings, for example, has 3 billion letters or bases. Around 99% of these bases are the same in all people. It is only the remaining 1% that makes each of us unique.

Where do we get our DNA?

We inherit our DNA from our parents, who got their DNA from their parents, who got it from their parents and on and on all the way back a few billion years ago when the very first life form appeared. This is why you may have blue eyes like your father or curly brown locks like your mother. Several diseases like sickle cell anemia, cystic fibrosis, hemophilia, and others can also be passed down to offspring through the DNA.

DNA inheritance (Photo Credit : HENADZI KlLENT/Shutterstock)

What is DNA? Everything You Need To Know

What is DNA?

Simply put, DNA (Deoxyribonucleic Acid) is a string of nitrogenous bases (Adenine, Thymine, Guanine, and Cytosine) repeated over and over, and arranged in a seemingly random fashion. Here the genetic code is contained. These bases are connected to each other through chemical bonds. Two complementary strands of DNA are bonded to each other, and are twisted in a helical structure. This extremely long double-stranded twisted string has parts that code for everything in all organisms. Different parts are under different selection pressures.

Below we will outline the history, structure of DNA, the differences and similarities between DNA and RNA. After this, we will then dive into why DNA is so important. Given how important this structure is, we will also talk about how it is replicated (DNA replication), packaged, and how these can be exploited or used for DNA fingerprinting.

History of DNA

The discovery of the structure of DNA opened many avenues in the field of biology. In 1962, Watson, Crick, and Wilkins obtained a Nobel Peace Prize for describing it. However, its existence was known of before that. In 1866, Gregor Mendel first hypothesized the existence of inherited entities, now known as genes. Later on (1869), Friedrich Miescher noted an acidic substance in the cell’s nuclei; this substance was referred to as nuclein (we now know this as DNA). Rosalind Franklin captured the famous X-Ray imagery clearly showing its double helical nature. It is her work together with that of the above-mentioned Nobel Laureates that gave us the gold mine (DNA) that has led to advances in all fields of biology; most notably, medicine.

This part of the DNA story is a lot more complex than this, but we will end here for the purpose of this lesson.

DNA Structure

DNA is a nucleic acid, hinted at in the name. Nucleic acids are the building blocks of all living organisms. Nucleotides simply refer to nitrogenous bases, pentose sugar together with the phosphate backbone. Nucleotides are adjacently strung together through a phosphate backbone and are held together with their complements through hydrogen bonds. The number of bonds holding nucleotides from the complementary strands depends on the type of nitrogenous base the nucleotide contains.

Figure 1: The chemical assembly of the three parts of the nucleotide (in this case adenine), the phosphate (blue box), nitrogenous base (red box) and the pentose sugar. Image Source: Wikimedia Commons

A nitrogenous base is a molecule with nitrogen that possesses the chemical properties of a base. These are crucial to the DNA as they define the genetic code (they are the code!). The pentose sugar connects the nitrogenous base to the phosphate backbone. There are four kinds of nitrogenous bases; namely, thymine (T), cytosine (C), adenine (A) and guanine (G). Guanine and adenine are purines while thymine and cytosine are pyrimidines. Purines have two rings (see adenine on figure 2) while pyrimidines have one ring. For the structure of the DNA to be able to twist and be packaged accordingly without bulging and the opposite bases to be able to pair up, a purine has to fit in a pyrimidine. To this end, the purine guanine pairs with the pyrimidine cytosine and the purine adenine pairs with the pyrimidine thymine.

Figure 2: The chemical structure of nucleotides and how they bond with their complements. Image Source: Wikimedia Commons

Differences and Similarities between DNA and RNA

Both molecules are nucleic acids made up of nucleotides, supported by a phosphate backbone. They are both major players in the central dogma. RNA is transcribed from the DNA to make proteins. DNA carries all the information needed for DNA replication and transfer new information to new cells.

They are involved in the maintenance, replication, and expression of hereditary information. DNA holds the key to heredity. RNA helps DNA unlock this code and show us what this code is capable of achieving. Together these molecules ensure that the DNA is replicated, the code is translated, expressed and that things go where they should go.

DNA and RNA work hand in hand in biology. It is rare that one can speak of the one without bringing up the other. Simply put, they are connected by the central dogma. The central dogma is the process of DNA transcription and translation for the purpose of protein synthesis which then perform a multitude of tasks in organisms. Different types of proteins guide the gene expression. Therefore, even though the DNA is the same throughout- different things happen at different part of the body. In addition to this, it also tells stem cells what to differentiate to. This is due to strict regulatory mechanisms in place to control gene expression.

Both DNA and RNA have a negative backbone (because of the phosphate group). They both have four nucleotides each, three of which they share (Guanine, Cytosine, and Adenine); with one significant difference, DNA has Thymine while RNA has Uracil. DNA is double-stranded while RNA is single-stranded. Last but not least, DNA is found in the nucleus while RNA resides both in the nucleus and the cytoplasm. DNA is long-lived while RNA is regenerated with each reaction.

They are both central to cell function.

DNA Packaging

How does DNA fit into the cell? Consider this; each and every one of your cells contains approximately 6 billion base pairs of DNA, with each base pair being 0.34 nanometers long. This works out to about 2 meters of DNA per diploid cell! If the DNA sequence is so long how does the nucleus manage to house the DNA and many other components necessary for the functioning of the cell? The answer is very simple, through condensing and packaging.

DNA is packaged with the help of histone proteins. Histones are small proteins with basic, positively charged amino acids; namely, arginine and lysine. They bind and neutralize the negatively charged DNA (because of the negatively charged phosphate backbone). It takes five types of histones to package DNA; H1, H2A, H2B, H3, and H4. Core histones (H2A, H2B, H3, and H4) with DNA coiled around them are referred to as nucleosomes. It takes two of each of the core histones to make up a nucleosome. Per nucleosome an H1 histone sits outside the coil holding the nucleosome intact. The nucleosome together with histone H1 are collectively referred to as chromatosome. The nucleosomes are condensed to fibers called chromatin. Bigger loops of tightly packed chromatin then make chromosomes.

Figure 3: Each of the steps involved in DNA packaging from the ladder phase through to the super coiled stage of hi stone complexes arranged into chromosomes. Image Source: Wikimedia Commons

Keeping DNA in a coiled and inaccessible state ensures DNA safety. As you can imagine, with this much coiling, twisting and packing the DNA is not accessible for transcription and/ or replication. This becomes redundant if the DNA cannot perform its functions. For DNA to perform its functions it needs to be unpacked and made accessible again. It is in this state that DNA can be replicated in order to, amongst other things; accommodate organism’s growth and maturity through cell division facilitated by DNA replication to ensure there is sufficient DNA in every cell.

DNA Replication

To understand DNA replication you will need to keep the following in mind:

– Replication duplicates the genetic information; this means you end up with a collection of identical DNA strands.

– The rules of DNA replication (A to T; G to C) govern replication.

– Each of the two strands DNA serves as a template of the new strand.

-DNA replication is essential for cell division.

Figure 4: The addition of nucleotides to the exposed hydroxyl group. Image Source: Wikimedia Commons

DNA replication takes place in 5’®3’ direction. This means that bases will be added from left to right direction. The template strand will guide this process by telling the new strand which base comes next, this will go on until the new strand is complete and the DNA will once again be double-stranded. Both strands of the old DNA will serve as templates of two new strands. This means that at the end there will be two double-stranded DNAs, identical to each other. This way once cell division occurs, the new cells will contain identical information as the rest of the body. A slew of proteins oversee the whole process make sure things happen at the right time and in the right way.

Figure 5: DNA replication from both the leading and the lagging strand. Image Source: Wikimedia Commons

Due to the complementary nature of DNA, one strand is in the 5’®3’ direction while the other is in the 3’®5’ direction. The fore is referred to as the lagging strand while the latter is called the leading strand.

In preparation for DNA replication, the double-strand unwinds and separate to form replication forks. Each template strand attracts the complements to the now exposed bases; this happens in a stepwise fashion. The back-bone solidifies and the DNA rewinds. This is a very simplified version of the process. What follows is the detailed version with the enzymes involved to guide the process.

An enzyme called helicase unwinds the template strands. The single strand binding proteins then stabilize the template strands in preparation for the replication, it holds it open until the end of the replication process. DNA polymerase III synthesizes nucleotides onto the leading end in the 5’®3′ direction.

The replication directed by the lagging strand, however, is a little more complicated. Helicase can only synthesize in the 5’®3′ direction, this poses a problem where the only available direction is 3’®5’. To get around this, Okazaki fragments are synthesized. Primase, as the name suggests, primes the synthesis of the new strand through synthesizing RNA primers to direct the addition of Okazaki fragments. Okazaki fragments are added onto the lagging strand by DNA ligase bonding the 3’ end to the 5’ of the previous fragment. The primers that prime the addition of the Okazaki fragments are then removed by DNA polymerase I and replaced by DNA bases. At the end of the process after the removal of the last primer there is an exposed 3’ end. DNA polymerase III completes the synthesis of the new strand, by adding DNA nucleotides at the end of the new strand. Nuclease provides proofreading services, correcting mistakes made during replication. As you can imagine, there will be a very tight coil at the end of the replication fork. Topoisomerase fixes this problem by making a small nick that releases the tension build up.

DNA Comparison and DNA Fingerprinting

DNA information has been used in comparative studies in order to understand not just where we stand as a species in the animal kingdom but where other species fit and how their genetic make-up influences their way of living. DNA fingerprinting, also called DNA profiling, refers to a technique of using a collection of individual specific regions of their genome. This is based on the idea that different combinations of various regions of the genome are very unlikely to be shared across individual. So, for example even though some of these sections can be shared between family members it is highly unlikely that they would all be identical between family members.

Different parts of the DNA code are under stricter selection pressures. This fact is one of the most exploited properties of the genome when studying organisms at different levels (e.g. population level, species level, genus level, etc.). Gene regions such as those coding for the internal transcriber region of the ribosome are under somewhat strict controls, and these evolve relatively slow. These, can, therefore, be used to study variations at the species level (species level marker). Other markers are under very little to no selection (neutral selection) and therefore evolve more freely, for example, simple sequence repeats such as micro satellites. These are more informative and can be used to study population dynamics. Some areas evolve so fast that they can be used to identify and different between individuals in a population to differentiating between individuals born of the same parents.

Figure 6: Chromatograph of a partial ITS DNA profile of an Ophiostomasplendens (Protea-associated fungus)

Using regions in the nuclear DNA to identify individuals, species or higher taxa is what we refer to as DNA bar coding. To study population dynamics markers such micro-satellites prove useful as their polymorphic profile can tell us a lot about how often intra and inter-breeding occur within and across populations. It can also give clues to infer modes of dispersal. To study evolutionary processes and phylogenetic relationships slow evolving markers such as mitochondrial DNA can be used. These can tell us where species sit in the bigger picture.

There are a large variety of fields in biology that exist because of the ability to study and manipulate the DNA code. These include fields such as genetic engineering; this is how you can enjoy summer fruits in winter. Other fields include gene therapy; here biologists use the knowledge of the genome to manipulate specific parts of the genome to remove lethal variants of some genes. The availability of techniques such as DNA fingerprinting also helps to better understand genetic diseases, and with the help of research such as that into CRISPR-CAS9, hopefully, enable us to cure diseases such as cancer.

Is DNA Important?

The simple answer is, yes, very much so. We hope at this point you agree with this answer. Just think of all the things DNA code for (pretty much everything). Now imagine life without them. What is left? Is any of it biotic?

DNA is what makes you special, alive and functional. Without DNA you would not exist. Everything you have, the thing you consider your best feature would not exist without DNA. DNA directs cell function. If there was no DNA, cell division would not happen—therefore no differentiation, this means you would not exist neither would your pet. Even though DNA is not solely responsible for life as we know it is still arguably the most important factor. Other factors include the environment and experience.
DNA is important for many reasons—so many in fact that we cannot list them all. To name a few it is important in the fields of genealogy, forensic science, agriculture, and virology.

Conclusion

In conclusion, DNA forms the basis for life. The discovery of the DNA structure has led to major strides in research, medicine, agriculture and many other fields. Given how important this structure is to our existence, it only makes sense that its description has affected so many areas of our lives. We hope at this point you have as much appreciation as we do for what DNA is and can do, how is differs from RNA, how many lives it has revolutionized and DNA fingerprinting. At this point, you should also have an appreciation for what DNA is in biology and what it means for this field.

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What Is DNA?

Elizabeth Yuko, PhD, is a bioethicist and journalist, as well as an adjunct professor of ethics at Dublin City University. She has written for publications including The New York Times, The Washington Post, The Atlantic, Rolling Stone, and more.

Chris Vincent, MD, is a licensed physician, surgeon, and board-certified doctor of family medicine.

Deoxyribonucleic acid—or DNA— is a molecule that serves as the hereditary material containing biological instructions that make every human and other organism unique. During reproduction, adult organisms pass their DNA and its set of instructions along to their offspring.

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Verywell / Jessica Olah

The Structure and Makeup of DNA

DNA is made up of nucleotides, which are essentially chemical building blocks. Nucleotides join together in chains to form a strand of DNA, and contain three parts: a phosphate group, a sugar group, and one of four types of chemical bases:

These chemical bases come together to create the information found in DNA, and stores it in a code, based on their sequence. A human genome—or the full set of instructions from DNA—contains about 3 billion bases and about 20,000 genes on 23 pairs of chromosomes.

Where DNA Is Found

DNA is found in nearly every cell of the human body. It is primarily located in the nucleus (where it is also referred to as «nuclear DNA»), though there is also a small amount in the mitochondria as well. Mitochondria are another part of human cells and are in charge of converting energy from food into a form that can power the cells.   Collectively, all the nuclear DNA in an organism is known as its «genome.»

How DNA Works

The purpose of DNA is to instruct organisms—including humans—on how to develop, survive, and reproduce. In order for this to happen, DNA sequences—known as «genes»—are converted into proteins, which are complex molecules responsible for carrying out most of the work in human bodies. While genes vary in size—ranging from about 1,000 bases to 1 million bases in humans—they only make up approximately 1% of the DNA sequence. The rest of the DNA sequences regulate when, how, and how much of a protein is made.  

It takes two separate steps to make proteins using instructions from DNA. The first is when enzymes read the information delivered in a DNA molecule and then transcribe it to a separate molecule called messenger ribonucleic acid, or mRNA. Once that happens, the information sent by the mRNA molecule is then translated into a language that amino acids—also known as the building blocks of proteins—can understand. The cell applies those instructions in order to link the correct amino acids together to create a specific type of protein. Given that there are 20 types of amino acids that can be put together in many possible orders and combinations, it gives DNA the opportunity to form a wide range of proteins.  

The Double Helix

To understand how DNA works, it’s important to go back to the four chemical bases mentioned earlier: A, G, C, and T. They each pair up with another base in order to create units called «base pairs.» Then, each base also attaches to a sugar molecule and a phosphate molecule, forming a nucleotide. When arranged in two long strands, nucleotides form what looks like a twisted ladder or spiral staircase known as a «double helix.» Using the example of a ladder, the base pairs are the rungs, while the sugar and phosphate molecules form the vertical sides of the ladder, holding it all together.  

The shape of the double helix is what gives DNA the capability to pass along biological instructions with great accuracy. This is the case because the spiral shape is the reason DNA is able to replicate itself during cell division. When it comes time for a cell to divide, the double helix separates down the middle to become two single strands. From there, the single strands function as templates to form new double helix DNA molecules, which—once the bases are partnered and added to the structure—turns out as a replica of the original DNA molecule.  

What does DNA stand for? Learn more about this important molecule!

Table of contents

DNA stands for “deoxyribonucleic acid,” and it is one of the most fascinating things you ever saw. Perhaps you remember it from school, but do you remember everything there is to it? This hard-to-pronounce name comes from its structure, a sugar (deoxyribose) and phosphate backbone (acid) with units called bases sticking out from it located in the cell’s nucleus.

DNA is the chemical molecule that carries genetic information in all living things. It is passed on from one generation to the next and holds the key to our survival on the planet. Almost every single one of the cells in the body contains an exact copy of DNA. This is due to a characteristic that sets it apart from any other molecule: the ability to copy itself.

In 1869, Friedrich Miescher was the first scientist to isolate nucleic acid. By 1952, it was confirmed that DNA is the molecule responsible for the passing of genetic information. Since then, scientists have engaged in an authentic race into knowing more about it. This has led to remarkable discoveries and so many practical uses, especially in the medical field. You have probably heard stuff about cloning or the production of insulin in a lab. All of that and so much more stem from our understanding of this structure.

What does DNA look like?

But what does it look like?

As you have seen in many images, including the one above, DNA looks like a twisted ladder. The “rungs” of a DNA molecule stand for small chemical bases: adenine (A), thymine (T), cytosine (C), and guanine (G). The “side rails” are composed of units called nucleotides, which are made of two substances: a phosphate group and a sugar.

Erwin Chargoff discovered in 1949 that even though different organisms have different amounts of DNA, the amount of adenine was always the same as thymine, and the amount of cytosine was always the same as guanine. This led to the conclusion that the ladder is composed of only A-T and C-G runs, called complementary bases, positioned in specific sequences that codify for particular characteristics.

But let’s take a closer look at this fascinating and unique molecule to understand why it is so fundamental to the perpetuation of life.

What is DNA made of?

This molecule’s chemical composition can be split into three major structural parts: a phosphate group, a deoxyribose sugar, and a nitrogenous base.

DNA is a polymer made of units called nucleotides. These nucleotides are joined together in rows through the chemical bond between the phosphate group of one and the deoxyribose sugar of the next and so on.

The two “railways” or “backbones” are joined together through weak hydrogen bonds between the nitrogenous bases (adenine and thymine; cytosine and guanine).

DNA stands for deoxyribose and acid: The “backbone” of DNA

This is like the “boring” part of DNA since it is a repetitive sequence, one after the other. Here we find the acidic phosphate group of one nucleotide bonded to the deoxyribose sugar of the next to form a long line of nucleotides.

DNA stands for nucleotides: The four bases of DNA

You can think of these as the exciting part of DNA. The nitrogen or nitrogenous bases make up the “letters” of your genome. The adenine from one strand bonds with the thymine of the other and the cytosine with guanine, creating an A-T and C-G order particular to each organism. Together with a deoxyribose and phosphate of the backbone, a nitrogenous base pair forms a nucleotide – the monomer of the large nucleic acid polymer.

Now that you know that DNA stands for deoxyribonucleic acid, have you ever wondered why it is classified as an acid? That’s because it is!

Does the word phosphate remind you of phosphoric acid? The acidity of DNA comes from this phosphate group.
An acid is defined as a substance that releases protons. Phosphoric acid (H₃PO₄), for instance, releases three protons. The only difference between phosphoric acid and the phosphate group is the replacement of two protons with protons from the sugar molecule of the nucleotide. The remaining proton is what makes the entire molecule acidic.

Where is DNA found in a cell?

Typically, genetic material is found in the cell’s nucleus, where it never leaves. However, a small amount of DNA can also be found in the mitochondria (mitochondrial DNA).

This DNA is cut in segments tightly coiled in the nucleus into structures called chromosomes. In humans, DNA is stored in 23 pairs of chromosomes (46 in total). This means that all the cells in your body contain this number of chromosomes packed inside the nucleus. This number varies among organisms. Corn, for example, has 20 chromosomes total in each cell, while dogs have 78.

Defining what DNA stands for: the Double helix

In its physical composition, DNA has the shape of a ladder that naturally coils into the famous double helix shape due to its weight and structure.

The Merriam-Webster dictionary defines a double helix as “a helix or spiral consisting of two strands in the surface of a cylinder that coil around its axis.” This definition applies especially to the structural arrangement of DNA.

The term was popularized by the 1968 book by James Watson (one of the discoverers of the DNA structure) titled The Double Helix: A Personal Account of the Discovery of the Structure of DNA.

James Watson and Francis Crick discovered this model of DNA in 1953, upon the grounds of the work of Rosalind Franklin, an X-ray crystallographer who took an X-ray diffraction photo of a DNA molecule. Then, aided by the work of other remarkable scientists, Watson and Crick were able to construct what we now know as the nucleic acid double helix.

Do all living things have DNA?

Fortunately for us, all living things have DNA since they all need instructions on building their anatomies, configure their physiology, and pass on these instructions to their offspring. Even microscopic organisms such as some viruses have DNA.

All living organisms store their hereditary information in the form of DNA. This information includes all the instructions for every genetic trait, from skin color to blood type; it is stored in DNA segments. These segments are what we call genes.

So, what is the difference between your DNA and the DNA found in a carrot, for example? The difference is the sequence of DNA base pairs A, T, C, and G. Think of it as the English alphabet letters. You can create two different stories with the same 26 letters.

The order or sequence of base pairs (A-T and C-G) varies from one organism to another. This sequence determines the instructions to produce insulin in humans and chlorophyll in plants, for example. A human’s DNA does not have the sequence that instructs chlorophyll production, and a plant’s DNA lacks the instructions for insulin.

But, if all cells in the human body have an exact copy of DNA, what is the difference between a bone cell and a skin cell, for example? That has to do with gene expression. Both cells activate the genes required for basic living processes, but only skin cells express the genes for skin proteins. So bone (and other) genes are silenced in this case.

You just saw how DNA has the same letters for all organisms. What is even more impressive is that the language of DNA is the same for all forms of life. Thus, a gene from an organism can be copied, transferred, and translated by any other living organism to produce the same protein.

Insulin is now created by a microbe that has been engineered with instructions from human DNA to produce human insulin. In other words, a copy of human genes for insulin production is copied and transferred to these microbes. These organisms have no blood or blood sugar, but they will produce insulin as they read the recipe to do so, even if they have no use for it.

What exactly does DNA do?

Remember, DNA stands for deoxyribose nucleic acid and is the repository of all bacteria, plant, and animal hereditary information. In any organism, every cell has the same base sequence as every other cell in that living organism.

Three distinct processes encompass DNA’s job to all organisms. These are replication, transcription, and translation.

It makes a copy of itself

Every cell in your body will divide through a process called mitosis. During this cell division, DNA copies itself via the process of replication.

So, how does DNA make a copy of itself?

Through a complex process involving enzymes, DNA uncoils into two single strands. Free nucleotides in the nucleus are bonded to each strand, complementing them and creating two exact copies.

DNA is the only molecule known to do this.

It sends blueprints to the cell to manufacture proteins

We mentioned earlier that DNA never exits the nucleus. So, what tells your cells what to do? This is where the process of transcription comes in. Through this process, DNA will create a blueprint that does exit the cell. This copy is known as RNA.

Transcription is an essential process to life as it sends the information out for cells to carry out their operations and manufacture large molecules called proteins, the building blocks of organisms. The process involves the uncoiling of DNA through specialized enzymes. Free nucleotides complement one of the strands, creating a unique strand (RNA) that acts as a blueprint that will exit the nucleus.

Many transcribed genes contain instructions for manufacturing proteins. This RNA will be read through the process of translation.

The genetic code

If you put together the words r, e, a, and d, you will get a grapheme that is “translated” into a sound; in this case, the word read. Similarly, a set of three consecutive nitrogenous bases are translated into a particular unit called an amino acid. Many amino acids put together form a protein.

This set of rules that determines what a gene in a DNA section stands for what amino acid is known as the genetic code. Simply put, the genetic code is used by living cells to translate encoded genetic information into proteins.

Just like in school you played games where you had to discover a secret message using a code, living cells will use this code to translate a “message” into actionable proteins.

Interesting facts about DNA and what it stands for

FAQ for What does DNA stand for?

How long is a DNA strand?

If you could uncoil the DNA in your chromosomes and stretch it out, it would be about 2 m (6 ft) long. Considering an estimated 37.2 trillion cells in your body, if you could put together every strand, the distance would be the equivalent of 96,000 round trips to the moon.

What are genes?

Genes are sections of DNA that codify for a protein. There are 20,000 of them in human DNA, which accounts for only 1.2%. The rest is noncoding DNA which scientists are only recently discovering has certain functions, like helping organize DNA in the nucleus and turning on and off gene expression.

Do all cells have the same DNA?

Yes, all living organisms have the same DNA but with different instructions among species.

What does DNA look like under a microscope?

You probably saw a project at a science fair called “DNA extraction.” In this case, DNA cells looked like strands of white noodles. But under a microscope, you can see the double-helix structure.

What is the difference between DNA and genes?

DNA is the molecule, and genes are sections of DNA. Take a look at the illustration below.

What is the difference between DNA and chromosome?

Chromosomes are packed bundles of DNA inside the nucleus. Every species has a distinct number of chromosomes in its cells.

What is the relationship between DNA bases and traits?

Traits in an organism are determined by the sequence of DNA bases.

Do all humans have the same DNA?

Yes, we do. In fact, we share about 99.8% of our DNA sequence.

Can a DNA test reveal if I have European ancestry?

Yes, a DNA test can reveal if you are more British than your brother, for example, by observing your DNA variations and comparing them to certain populations.

Get a reading of your DNA today!

DNA stands for deoxyribosenucleaic acid. There is a lot to DNA that we have been able to understand through the years. Your genome can reveal the genetic composition of your potential children or if your gene instructions make you more susceptible to a certain type of cancer. Through DNA, you can even find those ancestors you thought were lost.

In Nebula Genomics, we decrypt your entire DNA to provide you with the most comprehensive information of your genome. Imagine the whole new world that will unfold before your eyes! Our 30x Whole Genome Sequencing guarantees complete information on your genetic composition. Order your DNA test today!

Edited by Christina Swords, PhD

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Deoxyribonucleic acid (DNA) is an organic chemical that contains genetic information and instructions for protein synthesis. It is found in most cells of every organism. DNA is a key part of reproduction in which genetic heredity occurs through the passing down of DNA from parent or parents to offspring.

DNA is made of nucleotides. A nucleotide has two components: a backbone, made from the sugar deoxyribose and phosphate groups, and nitrogenous bases, known as cytosine, thymine, adenine, and guanine. Genetic code is formed through different arrangements of the bases.

The discovery of DNA’s double-helix structure is credited to the researchers James Watson and Francis Crick, who, with fellow researcher Maurice Wilkins, received a Nobel Prize in 1962 for their work. Many believe that Rosalind Franklin should also be given credit, since she made the revolutionary photo of DNA’s double-helix structure, which was used as evidence without her permission.

Gene editing today is mostly done through a technique called Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), adopted from a bacterial mechanism that can cut out specific sections in DNA. One use of CRISPR is the creation of genetically modified organism (GMO) crops.

DNA computing is a proposed computer architecture that would use the self-binding nature of DNA to perform calculations. Unlike classical computing, DNA computing would allow multiple parallel processes and calculations to occur at the same time.

DNA, abbreviation of deoxyribonucleic acid, organic chemical of complex molecular structure that is found in all prokaryotic and eukaryotic cells and in many viruses. DNA codes genetic information for the transmission of inherited traits.

A brief treatment of DNA follows. For full treatment, see genetics: DNA and the genetic code.

The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick, aided by the work of biophysicists Rosalind Franklin and Maurice Wilkins, determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other. The breakthrough led to significant advances in scientists’ understanding of DNA replication and hereditary control of cellular activities.

Each strand of a DNA molecule is composed of a long chain of monomer nucleotides. The nucleotides of DNA consist of a deoxyribose sugar molecule to which is attached a phosphate group and one of four nitrogenous bases: two purines ( adenine and guanine) and two pyrimidines ( cytosine and thymine). The nucleotides are joined together by covalent bonds between the phosphate of one nucleotide and the sugar of the next, forming a phosphate-sugar backbone from which the nitrogenous bases protrude. One strand is held to another by hydrogen bonds between the bases; the sequencing of this bonding is specific—i.e., adenine bonds only with thymine, and cytosine only with guanine.

The configuration of the DNA molecule is highly stable, allowing it to act as a template for the replication of new DNA molecules, as well as for the production (transcription) of the related RNA (ribonucleic acid) molecule. A segment of DNA that codes for the cell’s synthesis of a specific protein is called a gene.

DNA replicates by separating into two single strands, each of which serves as a template for a new strand. The new strands are copied by the same principle of hydrogen-bond pairing between bases that exists in the double helix. Two new double-stranded molecules of DNA are produced, each containing one of the original strands and one new strand. This “semiconservative” replication is the key to the stable inheritance of genetic traits.

Within a cell, DNA is organized into dense protein-DNA complexes called chromosomes. In eukaryotes, the chromosomes are located in the nucleus, although DNA also is found in mitochondria and chloroplasts. In prokaryotes, which do not have a membrane-bound nucleus, the DNA is found as a single circular chromosome in the cytoplasm. Some prokaryotes, such as bacteria, and a few eukaryotes have extrachromosomal DNA known as plasmids, which are autonomous, self-replicating genetic material. Plasmids have been used extensively in recombinant DNA technology to study gene expression.