DNA microarray

A DNA microarray (also commonly known as gene chip, DNA chip, or biochip) is a collection of microscopic DNA spots attached to a solid surface.Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome.
A DNA microarray is a multiplex technology used in molecular biology and in Medicine. It consists of an arrayed series of thousands of microscopic spots of DNA oligonucleotides, called features, each containing picomoles (10⁻¹² moles) of a specific DNA sequence, known as probes (or reporters). This can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target. Since an array can contain tens of thousands of probes, a microarray experiment can accomplish many genetic tests in parallel. Therefore arrays have dramatically accelerated many types of investigation.

In standard microarrays, the probes are attached via surface engineering to a solid surface by a covalent bond to a chemical matrix (via epoxy-silane, amino-silane, lysine, polyacrylamide or others). The solid surface can be glass or a silicon chip, in which case they are colloquially known as an Affy chip when an Affymetrix chip is used. Other microarray platforms, such as Illumina, use microscopic beads, instead of the large solid support. DNA arrays are different from other types of microarray only in that they either measure DNA or use DNA as part of its detection system.

DNA microarrays can be used to measure changes in expression levels, to detect single nucleotide polymorphisms (SNPs) , to genotype or resequence mutant genomes.

Denaturation

Denaturation is a process in which proteins or nucleic acids lose their tertiary structure and secondary structure by application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent (e.g., alcohol or chloroform), or heat. If proteins in a living cell are denatured, this results in disruption of cell activity and possibly cell death. Denatured proteins can exhibit a wide range of characteristics, from loss of solubility to communal aggregation. Denaturization in this sense is not used in preparing the industrial chemical denatured alcohol.

Denaturation is the alteration of a protein shape through some form of external stress (for example, by applying heat, acid or alkali), in such a way that it will no longer be able to carry out its cellular function.

Denatured proteins can exhibit a wide range of characteristics, from loss of solubility to communal aggregation.

Proteins are very long strands of amino acids linked together in specific sequences.

A protein is created by ribosomes that "read" codons in the gene and assemble the requisite amino acid combination from the genetic instruction, in a process known as translation.

The newly created protein strand then undergoes post-translational modification in which additional atoms or molecules are added, for example copper, zinc, iron.

Once this post-translational modification process has been completed, the protein begins to fold (spontaneously, and sometimes with enzymatic assistance), curling up on itself so that hydrophobic elements of the protein are buried deep inside the structure and hydrophilic elements end up on the outside.

The final shape of a protein determines how it interacts with its environment.

Plasmid Isolation (Alkaline Lysis)

Bacterial plasmids, the non-genomic transferable DNA, can easily be purified from bacteria using numerous techniques. The purification of DNA is important for genetic research as it provides a source of transferable DNA and allows researchers to isolate large amounts of recombinant DNA. One common technique for plasmid purification is the alkaline lysis method, which breaks open bacteria with an alkaline solution, proteins are removed by precipitation and the plasmid DNA is recovered with alcohol precipitation.

Students purify bacterial plasmids from a liquid culture using this alkaline lysis method.

Protein Function

Proteins are very important molecules in our cells. They are involved in virtually all cell functions. Each protein within the body has a specific function. Some proteins are involved in structural support, while others are involved in bodily movement, or in defense against germs.

Proteins vary in structure as well as function. They are constructed from a set of 20 amino acids and have distinct three-dimensional shapes. Below is a list of several types of proteins and their functions.

Protein Functions

Antibodies - are specialized proteins involved in defending the body from antigens (foreign invaders). One way antibodies destroy antigens is by immobilizing them so that they can be destroyed by white blood cells.

Contractile Proteins - are responsible for movement. Examples include actin and myosin. These proteins are involved in muscle contraction and movement.

Enzymes - are proteins that facilitate biochemical reactions. They are often referred to as catalysts because they speed up chemical reactions. Examples include the enzymes lactase and pepsin. Lactase breaks down the sugar lactose found in milk. Pepsin is a digestive enzyme that works in the stomach to break down proteins in food.

Hormonal Proteins - are messenger proteins which help to coordinate certain bodily activities. Examples include insulin, oxytocin, and somatotropin. Insulin regulates glucose metabolism by controlling the blood-sugar concentration. Oxytocin stimulates contractions in females during childbirth. Somatotropin is a growth hormone that stimulates protein production in muscle cells.

Structural Proteins - are fibrous and stringy and provide support. Examples include keratin, collagen, and elastin. Keratins strengthen protective coverings such as hair, quills, feathers, horns, and beaks. Collagens and elastin provide support for connective tissues such as tendons and ligaments.

Storage Proteins - store amino acids. Examples include ovalbumin and casein. Ovalbumin is found in egg whites and casein is a milk-based protein.

Transport Proteins - are carrier proteins which move molecules from one place to another around the body. Examples include hemoglobin and cytochromes. Hemoglobin transports oxygen through the blood. Cytochromes operate in the electron transport chain as electron carrier proteins.

Polymers

A polymer is a substance with a high molecular mass that is composed of a large number of repeating units. These units, called monomers, are connected by covalent chemical bonds.

Some polymers are composed of a single type of monomer, while others may consist of two, three or more different monomers. Many biological macromolecules are examples of natural polymers. These include the carbohydrates, starch, cellulose and glycogen (branched chains of glucose monomers), and chitin (chains of N-acetyl-glucosamine). Examples of polymers consisting of mixtures of monomers are the nucleic acids, DNA and RNA, made from units of 4 different nucleotides, and proteins, which consist of a mixture of the 20 standard amino acids. Natural rubber, or latex, is a natural hydrocarbon polymer found in the sap of some plants. Natural, biological polymers have both structural roles and physiological functions, and are involved in the control of cellular operations such as growth, replication and metabolism.

Synthetic polymers can be produced commercially, and are traditionally derived from petroleum products. They have a wide variety of properties and uses. The most common synthetic polymers are plastics such as polyethylene and nylon. Synthetic polymers made out of glycolic and lactic acids, and other biodegradable materials, have become increasingly popular for use in biomedical applications. Man-made polymers that react to their surroundings are known as smart polymers, or stimulus-responsive polymers, and can be used for a variety of purposes in technology and biomedicine.

DNA Transcription

DNA transcription is a process that involves the transcribing of genetic information from DNA to RNA.

DNA is housed within the nucleus of our cells. It controls cellular activity by coding for the production of enzymes and proteins. The information in DNA is not directly converted into proteins, but must first be copied into RNA. This ensures that the information contained in the DNA does not become tainted.

DNA Transcription

DNA consists of four nucleotide bases [adenine (A), guanine (G), cytosine (C) and thymine (T)] that are paired together (A-T and C-G) to give DNA its double helical shape.

DNA is transcribed by an enzyme called RNA polymerase. Specific nucleotide sequences tell RNA polymerase where to begin and where to end. RNA polymerase attaches to the DNA at a specific area called the promoter region. The DNA strand opens and allows RNA polymerase to transcribe only a single strand of DNA into a single stranded RNA polymer called messenger RNA (mRNA).

Like DNA, RNA is composed of nucleotide bases. RNA however, contains the nucleotides adenine, guanine, cytosine and uricil (U). When RNA polymerase transcribes the DNA, guanine pairs with cytosine and adenine pairs with uricil. RNA polymerase moves along the DNA until it reaches a terminator sequence. At that point, RNA polymerase releases the mRNA polymer and detaches from the DNA.

Since proteins are constructed in the cytoplasm of the cell by a process called translation, mRNA must cross the nuclear membrane to reach the cytoplasm. Once in the cytoplasm, mRNA along with ribosomes and another RNA molecule called transfer RNA, work together to produce proteins. Proteins can be manufactured in large quantities because a single DNA sequence can be transcribed by many RNA polymerase molecules at once.

DNA and Neurological Disease

Neurological diseases are devastating for sufferers and can be some of the most difficult diseases to treat. They may impact a person's daily life, including their mobility. They can also progressively worsen, which is painful for friends and family members when they watch a loved one deteriorate each day. Research into the mechanism of DNA as a basis for neurological diseases, however, has suggested promise for improving our understanding of the diseases and hopefully developing successful treatments one day.

What are Neurological Diseases?

Neurological diseases are disorders that involve the spinal cord, brain and also nerves in your body. These three parts exert a great deal of control over how your body works, which includes speech, movement, swallowing, breathing or thinking. A person's ability to recall information and their moods can also be affected. Examples of neurological diseases include:

• Alzheimer's disease
• Bell's Palsy
• Huntington's disease
• Epilepsy
• Parkinson's disease
• Cerebrovascular disease

DNA and its Relationship to Neurological Diseases

Research over the last several years has found that long sequences of abnormal DNA can cause extremely debilitating and rare neurological diseases. Researchers are trying to understand how these abnormalities actually occur in the DNA. In one study, the focus was on a neurological disorder called Friedreich's ataxia, which is damaging to the nervous system and gradually worsens over time. Those with the disease suffer from weakened muscles and difficulties speaking as well as heart disease.

If you recall that DNA reads bases in sets of three, you may more easily understand that in Friedreich's ataxia, a DNA triplet repeats itself - a guanine and two adenine bases, which are denoted by the first letter of each base, resulting in GAA. Since DNA base pairing is very specific, the complementary strand is two thymines and one cytosine, denoted by TTC. It was initially found that forty repeats of the triplet could occur without symptoms showing but we know that if more than forty repeats occur, many problems begin to take root. Also concerning is that the DNA itself is inherited, which is not particularly worrying if the pattern is less than forty repeats but it does become a problem when it occurs in greater numbers. The reason for this phenomenon is that the increasing number of repeats makes the sequence unstable. It also means that the sequence increases in each new generation. Unfortunately, the longer sequence causes more devastating effects from the disease.

DNA and Disease Prediction

DNA has become an extremely useful tool for predicting disease. By allowing medical professionals to identify genes in DNA that are markers for disease, a person can make appropriate lifestyle or similar modifications to help lower the risk of disease. For those diseases that are inherited, identifying a parent who is a carrier but does not express the disease can also help parents make informed choices regarding a potential pregnancy.

Predicting Heart Disease

The incidence of heart disease continues to rise in the United Kingdom (UK) and many other parts of the world. Heart disease is a complex interplay of lifestyle factors and genetics. Recently, researchers in the UK found a method for identifying those individuals who have an elevated risk of heart disease. They found that telomeres - miniscule DNA strands that are found at the ends of chromosomes - could provide valuable information about a person's chances of having heart disease. It was found that shorter telomeres suggested a greater risk of developing heart disease in men aged forty-five to sixty-four years old.

The telomeres were measured in leukocytes, also known as white blood cells. Researchers believe that as telomere length decreases, a person's chromosomes are more likely to mutate. This relates to the protective effect of telomeres, which help to prevent damage to chromosome ends. The research can hopefully allow medical professionals to eventually predict someone's risk of heart disease, which will mean allowing us to find new ways to prevent heart attacks.

Predicting Brain Disorders

Brain disorders such as Parkinson's disease and amyotrophic lateral sclerosis (ALS) are progressive disorders that lead to destruction of brain cells and functioning. In ALS, muscle use and mobility are lost, leading to death. Parkinson's disease results in tremors and compromised movement. Like ALS, no cure exists for Parkinson's disease, which means that research is vital to help scientists find effective treatments or a cure. New research has, however, provided clues about predicting these diseases.

In a research study based in the United States, scientists looked at data from people with ALS and Parkinson's disease as well as those who did not have the diseases. They found differences in genes that allowed them to predict those individuals who had an increased risk for the diseases.

These differences were noted after researchers investigated the axon guidance pathway. This pathway involves a complicated group of chemically mediated messages that are important in the brain during foetal growth. They work to support and repair the 'wiring' of the brain during a person's entire life. There were numerous differences in the pathway genes that relate to these diseases. In addition, researchers also found pathway genes that identify people at a very high risk of ALS, several thousand times that of the general population.

For Parkinson's disease, they discovered pathway genes that suggested a very high risk of approximately four hundred times that of the general population. It is hoped that for individuals who have a higher risk of the diseases, scientists will be able to create drugs that can target these pathways.

Bioinformatics and DNA

Understanding Bioinformatics

Bioinformatics involves applying computer technology to the handling and sorting of biological information. As such, we can use computers to analyse and make sense of this biological information. In a sense, bioinformatics is a bridge between the biological sciences and computer sciences. With so much information, bioinformatics can let us detect valuable data contained within enormous volumes of biological information. Once uncovered, this information can be applied to technological applications in fields such as medicine, agriculture, environmental sciences and nutrition.

Importance of Bioinformatics

Bioinformatics is important to a virtually unlimited number of fields. However, one of its biggest challenges is to obtain clarity within the massive amount of information that results from projects involving the sequencing of the human genome. Initially, this type of sequencing was performed solely in the laboratory but with such an enormous level of data production, we now rely on computers to accomplish sequencing goals.

To actually generate a DNA sequence and then store and analyse it, computers are responsible for much of the work. However, it is a challenge in bioinformatics to efficiently and successfully store such a large volume of data and to do so in such a way that a scientist can easily access the necessary information as needed. Data in itself is almost useless until it is analysed and correctly interpreted. To handle so much data, computers are important to fill this vital gap, which can aid scientists in the extraction of useful and important biological data.

Using Bioinformatics

Bioinformatics is used in many aspects of medicine and will likely continue to grow as we find new capabilities and applications. It has the potential to create custom medications, prevent or treat disease, benefit the environment or support agricultural technology.

In molecular medicine, we can obtain a higher number of drug targets through the use of bioinformatics. Another important area is that of gene therapy, which is a particularly strong focus of research at present. In agriculture, bioinformatics can allow us to enhance the nutrient quality of foods and develop crops that are able to handle poor soil growing conditions and bad weather. We can also develop our understanding of evolution through bioinformatics as well as broaden our understanding of environmental issues such as climate change. Clearly, bioinformatics is a significant area of science and it will continue to develop and support our research and understanding of DNA and the biology of organisms.

DNA Vaccines

Why Use DNA Vaccines?
There are numerous advantages of DNA vaccines over other vaccination methods. DNA vaccines are thought to trigger a broader range of immune responses, which means they would have more applications than traditional vaccines. Since traditional vaccines only cover certain diseases, the use of DNA vaccines to target a larger number of diseases could impact virtually everyone, given how easy it is to come into contact with one of the many diseases that exist.

Comparison of DNA Vaccines and Other Vaccines
To understand DNA vaccines it helps to have a sense of the differences between DNA vaccines and other vaccines used to protect from disease. First generation vaccines are those involving the entire organism, which may be live, 'damaged' or dead. Those vaccines that are live and attenuated trigger an antibody immune response as well as those entailing killer and helper T-cells. Still, there is a low chance that attenuated vaccines can still change to the toxic form, which means that in people with already weakened immune systems the vaccine could cause disease. Although vaccines that are killed do not have the same risk, they are not as effective in addressing a wide range of diseases.

Second generation vaccines were developed to address some of the concerns held regarding first generation vaccines. Second generation vaccines are subunit ones that are made up of mostly protein parts such as protein antigens or recombinant proteins although they do not trigger a killer T-cell response.

DNA vaccines constitute a third generation vaccine. These are comprised of a round, relatively small bit of bacterial DNA that has been modified to release one or more particular proteins - also known as antigens - from a microbe. After injection of the DNA vaccine, the recipient's cells translate the DNA into toxic proteins that are viewed as foreign invaders, which serves to begin an immune response.

Benefits of DNA Vaccines
DNA vaccines have many benefits in comparison with the more traditional types of vaccines. For instance, DNA vaccines are thought to provide a better immune response in patients with HIV. Patients with HIV suffer from poor immunity and increased susceptibility to disease. Since DNA vaccines afford the potential for treating chronic viral infections, they could be particularly beneficial for individuals with diseases such as HIV. DNA vaccines are considered cheaper to produce than traditional vaccines and thus provide an affordable way to provide large-scale vaccinations. Since DNA vaccines are also more stable with regards to temperature, they are easier to store and transport.

Limitations of DNA Vaccines
Thus far, the limitations of DNA vaccines mostly involve a lack of research, which will likely be remedied in the future when they become a more important area of interest. At present, there is a limitation in regards to microbial activity. While DNA is successful for providing an immune response when the target involves disease-causing proteins, there are some microbes that have an outer shell made of polysaccharides. Unfortunately, DNA vaccines are unsuccessful and instead, subunit vaccines that have a polysaccharide foundation are required.

Vaccines remain one of the most important developments of the twentieth century and they are responsible for saving millions of lives and even eliminating disease in some areas. Vaccines allow us to keep disease in controlled numbers and prevent the complications that arise when someone is afflicted with a disease.

DNA Mutations

How do DNA Mutations Occur?
Virtually every single person will have some sort of change to their DNA during their life. Changes can result from a multitude of mistakes, such as an error when DNA is replicated or through damage to DNA occurring from environmental or lifestyle factors. These include smoking, radiation and many others. Fortunately, your cells have special ways to handle these mistakes before they can cause damage. For some people, however, their body's repair systems can become overwhelmed if repeatedly exposed to a specific stimulus. For all of us as well, our DNA repair systems just do not operate nearly as successfully as we age. The end result for both of these scenarios is that changes in DNA will occur.

A DNA mutation can also be inherited. A germline mutation is one that can result in a disease that is clustered within one family. Some mutations can be quite specific, such as those that occur following excessive exposure to sunlight, which can cause changes in skin cells. Still other mutations may occur in the area of DNA related to sperm and egg production, which is also considered a germline mutation and is inheritable. If your child were to inherit a germline mutation from you, each cell in your child's body would carry this faulty DNA.

Differnet Types of Mutations
To understand the different types of mutations that can occur, it is important to know how a gene is constructed. Your DNA is full of genes, which are similar to words that make up a sentence. The four bases are known as adenine (A), thymine (T), guanine (G), and cytosine (C), each denoted by their first letter. Different sequences of these bases code for different proteins. If the sequence is modified, the entire meaning of the gene then changes and the instructions for producing the protein changes as well.

Point mutations are those that involve a basic change in a single base for the sequence. If we removed just a single letter from in a word or sentence, this would be akin to a point mutation. In contrast, a frameshift mutation involves the addition or removal of nucleotides. At the same time, if you think about the fact that DNA reads in sequences of three bases or 'letters,' the addition or removal of one or more letters alters every word that follows as the letters are all shifted. Therefore, the entire meaning of the sentence is changed.

Another type of mutation is a deletion mutation. Any mutation where DNA is ultimately missing a piece is called a deletion mutation. The mutation may be quite small and could involve deletion of only a single base or it could be larger and will impact numerous genes. A deletion mutation can even result in a frameshift mutation, where an entire 'word' is deleted. Conversely, a mutation that involves an additional piece of DNA is called an insertion mutation. In fact, these types of mutations can also result in frameshift mutations. Regardless of whether it is a deletion or insertion, a frameshift mutation usually translates into a protein that does not function properly.

Other mutations include inversion and expression mutations. In the latter, a whole section of a person's DNA is actually reversed while in an expression mutation, it is not just the protein that may be changed but the location where it is made or the amount of the protein produced. So basically, if you had this mutation, your body could be making a protein in a skin cell, for example, when it should be making it in a nerve cell.

There are obviously many different types of mutations but keep in mind that even if DNA repair is unsuccessful, the end result is not necessarily anything major or noticeably detrimental to your health. While the functions of DNA are important, many mutations happen that fortunately do not have dire consequences such as disease.

DNA Viruses

Most people encounter viruses at some point throughout their lifetime, which can leave them feeling miserable. We probably don't give a lot of thought to the molecular aspects of viruses and instead, just focus on getting rid of the painful symptoms when a virus strikes and compromises our health. If you stop for a minute and think about it, however, a lot is happening in our bodies when a virus invades. All of the symptoms you feel result from the collective effects of a virus as it inflicts your body's cells.

How Do Viruses Work?

A virus essentially inserts its own genetic material into a host cell and causes changes in the function of the host cell through the virus' genes. The host cell may lose many different abilities, such as control over its growth, its ability to divide and it may also show chromosomal abnormalities.

Like humans, viruses are composed of genetic material. In the case of a DNA virus, this genetic material is DNA. A DNA virus uses a copying mechanism, which relies on an enzyme called DNA polymerase - an important enzyme in DNA replication. DNA viruses are grouped according to the Baltimore classification system and there are more than twenty virus families and nearly a hundred genera. The viruses themselves include an enormous range, from more basic ones to highly complex viruses.

Different Kinds of DNA Viruses

There are numerous different groups of DNA viruses, with varying structures and effects. One group is herpes viruses, which are somewhat complex and have over one hundred genes. One of the herpes family of viruses is the Epstein Barr virus, which has been associated with a rare form of cancer. Epstein Barr virus is also the virus responsible for glandular fever - formally known as infectious mononucleosis, which is commonly seen in adolescents and college-aged adults. Pox viruses have several hundred genes and are effective at replicating once in a host. Papilloma viruses are those that cause warts and they are also associated with cancer. You have also likely heard of the Hepatitis B virus, which is actually a DNA tumour virus. There are many more DNA viruses but they all share a common link, which is that their genetic material is comprised of DNA.

Creating a DNA Virus

In some interesting research, scientists in the United States actually created a DNA virus with a new method that appears to be promising. The development of the virus could potentially lead to technologies for the production of cleaner forms of energy or even novel ways to buffer the effects of pollution. To create the virus, researchers put together and selectively cut segments of DNA. The process itself took approximately two weeks, which is not particularly long given the potential of the development. One exciting aspect of the research is that scientists believe that their ability to rapidly make longer pieces of DNA can allow them to improve understanding of specific genes. Their understanding could then be a turning point for the ability to eventually modify more complicated organisms.

While DNA viruses have many different effects in the body, our knowledge of their structure and mechanisms of infection can help us to learn more about treating diseases caused by DNA viruses. Better still, research has suggested that the creation of synthetic viruses can provide possibilities for addressing concerns such as pollution and the quest for better forms of energy provision.

Cancer and DNA

With hundreds of thousands of Britons receiving a cancer diagnosis each year and millions around the world being diagnosed, the aim to successfully treat cancer is an important one for researchers. Our knowledge of cancer thus far has shown it to be a complex disease that involves numerous factors such as genetics, lifestyle and environmental factors. The area of genetics is a particularly vital one because it is suggested that our genes are the starting point for disease susceptibility and in some cases, genetics are the determining factor while in other cases, this predisposition to cancer can be triggered by lifestyle and the environment.

DNA Damage and Cancer

DNA damage is not an unusual or isolated event. Rather, we all suffer from DNA damage within cells during our lives. When DNA is copied, many mistakes can and do occur - the process is not a perfectly efficient one. As such, mistakes will occur and these may be rapidly repaired by DNA repair systems or they may accumulate, particularly due to ageing or if the body is repeatedly exposed to a harmful stimulus over time. Add to this the fact that by-products from normal metabolism and other required reactions in our bodies may trigger damage to DNA, and you can see how damage to our DNA can actually occur quite easily.

If you think about other aspects of life, such as your environment, consider things like smoke, radiation from the sun and other toxins. All of these parts of our day-to-day environment can cause repeated damage to DNA in cells. The consequences can mean a constant barrage of damage throughout the day, all of which each of your cells must withstand. Yet, not everyone ends up developing cancer, so clearly the combination of the body's repair systems, biochemistry, familial history, lifestyle and likely many still unknown factors come together to protect the body from cancer. In most cases as well, a cell can repair damage to DNA quite well and the body has some resilience to mistakes in DNA copying. In fact, even major DNA damage can be addressed through signals for cell apoptosis, which is the way a cell is programmed to die where appropriate.

When DNA Repair is Unsuccessful

Even with your body's systems of repair and resilience to damage, the body can still become overwhelmed with damage and cancer can occur. Also perhaps surprising is that cancer can be caused by malfunctions and mutations in the genes that govern the cell repair itself. This means that mutations may initially occur, followed by mutations in the mechanisms for repairing these initial problems. Thus far, genes have fortunately been identified with regards to mutations linked to cancer.

You may have even heard the terms already in the media. The first are tumour suppressor genes, which work to fix DNA errors, direct apoptosis and also affect the rate of cell division. If damaged, tumour suppressor genes can lead to cancer. The second are oncogenes, which are mutated forms of normal genes known as proto-oncogenes. Oncogenes carry DNA sequences known to lead to cancer. There are, of course, other genes that can mutate and may also improve a cancer's ability to persevere in a person's body. Such genes may facilitate 'better' delivery of the cancer to other areas of the body or may work to shield injured cells from apoptosis.

Differences between DNA and RNA

DNA and RNA are two molecules that are found in the cells of every organism. DNA stands for Deoxyribonucleic acid while RNA is short for Ribonucleic acid. Both have specific functions related to the growth and replication of the organism through cell division and protein synthesis. However, DNA and RNA have differences in both structure and use.

The main difference between DNA and RNA molecules is the type of sugar that is present in them. DNA is composed of deoxyribose sugar while RNA is made up of ribose sugar. The main difference between the two sugars is that deoxyribose has more OH.

Another difference between DNA and RNA is their predominant structure. DNA is a double-stranded molecule with a long chain of nucleotides while RNA is a single-stranded molecule having shorter chains of nucleotides. Both DNA and RNA are polymers however; each molecule has its own set of bases. The difference in DNA and RNA bases is that RNA has the base uracil, and DNA has a base of thymine.

The difference in roles each of these molecules has in cell biology is: DNA serves as the storage of genetic information of an organism, while RNA acts as a messenger that relays the genetic information from the nucleus to the ribosome.

DNA and RNA

DNA

DNA, short for Deoxyribose nucleic acid, is the chemical that is found inside the nucleus of the cells of all organisms. It carries the vital genetic codes that dictate how an organism will grow and shape. Each DNA molecule consists of two long strands that are wrapped around each other. Because of this, the DNA structure resembles a double spiral "staircase" or a helix. An actual microscope photo of a DNA stand is shown in the below figure:

Each rung of the DNA ladder is composed of two substances, known as bases, which lock together. All in all, there are four different types of bases, and together they create four different kinds of rungs. The exact DNA sequencing of these rungs makes up a cell’s chemical information. This DNA information is vital since it shapes the cell’s development and regulates every single detail of how a cell should work. DNA contains chemical information known as genes. These genes are individual instructions in the code that tells the body’s cells how to produce new proteins.

DNA replicates before cell division so that a full set of DNA information is given to each new cell. During cell division, DNA molecules tighten up to form chromosomes. These chromosomes undergo a series of events and eventually replicate so that each new cell will have the same genetic information found in the originals, and the newly-formed cells will function the same way as those of the parent cells.

RNA
In order to better understand what Ribonucleic Acid (RNA) is, it is first important to know what is happening inside an organism’s cell.

Inside every living cell, the actual process of creating new proteins undergoes several different steps and the instructions for these steps are contained in the nucleus of the cells. However, the proteins themselves are synthesized outside the nucleus, in an area known as the cytoplasm. This means that the cells must have a way to relay the information contained in the nucleus towards the cytoplasm. As it turns out, cells utilize a special molecule known as the messenger RNA to transcribe the genetic code found inside the nucleus.

RNA is very similar to DNA, Deoxyribonucleic acid, which contains the vital genetic information of the cell. RNA, when compared to DNA, has only a single strand and has a ribose sugar instead of the deoxyribose sugar. Furthermore, the base of the RNA is Uracil instead of Thymine which is found in DNA. RNA is produced by the RNA polymerase enzyme. This enzyme is responsible for RNA synthesis.

Whenever new proteins are needed by the cell, it sends a chemical signal to the nucleus which causes a gene for that protein to be 'switched on'. When this happens, the DNA codes are copied to the messenger RNA in the process known as genetic transcription. After the codes have been copied, the messenger RNA carries the information to the ribosome which is responsible for the protein synthesis. The messenger RNA then releases the codes to the transfer RNA which eventually translates the codes in the right order inside the ribosome.

Once the code is being translated in the ribosome and the required protein is synthesized, a mechanism known as RNA interference takes place, turning off the gene so it doesn't send more messenger RNA to the ribosome.

DNA and RNA

DNA and RNA are two different nucleic acids found in the cells of every living organism. Both have significant roles to play in cell biology. DNA and RNA structure are similar because they both consist of long chains of nucleotide units. However, there are a few structural details that distinguish them from each other, and if you are to compare DNA and RNA, these would be the results:

(1) RNA is single-stranded while DNA is a double-stranded helix.

(2) RNA also has uracil as its base while the DNA base is thymine. However, even with the differences in their structures, DNA and RNA have cooperating roles in the field of Cell Biology.

DNA contains the genetic information of an organism, and this information dictates how the body’s cells would construct new proteins according to the genetic code of the organism. Within the cell structure, DNA is organized into structures called chromosomes, which are duplicated during cell division.

These chromosomes would then release the genetic codes that will be transcribed and carried by the RNA (specifically the messenger RNA) to the ribosome. The ribosome will then synthesize new proteins that will help the body grow. This is the how the DNA and RNA work together in the body.

DNA-RNA-Protein Introduction

DNA carries the genetic information of a cell and consists of thousands of genes. Each gene serves as a recipe on how to build a protein molecule. Proteins perform important tasks for the cell functions or serve as building blocks. The flow of information from the genes determines the protein composition and thereby the functions of the cell.

The DNA is situated in the nucleus, organized into chromosomes. Every cell must contain the genetic information and the DNA is therefore duplicated before a cell divides (replication). When proteins are needed, the corresponding genes are transcribed into RNA (transcription). The RNA is first processed so that non-coding parts are removed (processing) and is then transported out of the nucleus (transport). Outside the nucleus, the proteins are built based upon the code in the RNA (translation).

The document has two levels, basic and advanced. This page is an introduction to both levels. You start at the basic level, then you can advance if you want more and deeper information.