DNA is the inherited genetic material that controls gene expression through protein synthesis. This is a fancy way of saying that DNA is a chemical form of a genetic blueprint. The genetic instructions contained in DNA are housed in genes.
Genes are smaller segments that, when strung together, comprise a DNA molecule. They are unique linear sequences of nucleotide monomers named for the nitrogenous base they contain. Nucleotide monomers, or nucleotides, are the building blocks of genes. The chemical structure of DNA is important because biology and chemistry are uniquely intertwined.
A nucleotide monomer can be chemically broken down into three parts. The first part is a five-carbon sugar, also called a pentose sugar. The second part is a central phosphate atom bonded to a ring of four oxygen atoms, also called a phosphate group. The third part is one nitrogen-containing base from a possible four: Thymine, cytosine, adenine, or guanine.
The four bases, A, C, T, or G, are categorized into two types: Purines and pyrimidines. Purines are chemically a double-ringed structure, whereas pyrimidines form a single ring. Adenine and guanine are classified as purines, while cytosine and thymine are pyrimidines.
The chemistry of DNA hinges on precise bonding between pyrimidines and purines. This unique bonding pattern is what unites two DNA strands together. The structure formed from these precise chemical interactions is termed a double helix.
The twisted shape of DNA is what led researches to coin the term double helix. A molecule of DNA is two single strands joined together by hydrogen bonds. A single strand of DNA is likened to a ladder that has been cut down the middle, resulting in two halves.
One strand complements the other in a way that is also related to chemical structure. The component nucleotides make the rungs of the ladder. The nucleotides in the first strand of DNA, the left side of the ladder, pair with nucleotides in the second DNA strand or the right side of the ladder. Together, the two DNA strands unite to form what looks like one single ladder.
For genes to properly function, the nucleotides must pair correctly. They do this by adhering to a strict set of base-pairing rules that were discovered by pioneers in the science of genetics, James Watson and Francis Crick. Base-pairing rules dictate that a purine always pairs with a pyrimidine. In other words, adenine always pairs with thymine and cytosine always pairs with guanine.
The hydrogen bonds formed between nucleotide pairs are important to the structure of DNA. These weak bonds, along with complex bonding among other molecular elements are what give DNA its twisted appearance. This particular shape is why DNA is aptly named a double helix. - 16747
Genes are smaller segments that, when strung together, comprise a DNA molecule. They are unique linear sequences of nucleotide monomers named for the nitrogenous base they contain. Nucleotide monomers, or nucleotides, are the building blocks of genes. The chemical structure of DNA is important because biology and chemistry are uniquely intertwined.
A nucleotide monomer can be chemically broken down into three parts. The first part is a five-carbon sugar, also called a pentose sugar. The second part is a central phosphate atom bonded to a ring of four oxygen atoms, also called a phosphate group. The third part is one nitrogen-containing base from a possible four: Thymine, cytosine, adenine, or guanine.
The four bases, A, C, T, or G, are categorized into two types: Purines and pyrimidines. Purines are chemically a double-ringed structure, whereas pyrimidines form a single ring. Adenine and guanine are classified as purines, while cytosine and thymine are pyrimidines.
The chemistry of DNA hinges on precise bonding between pyrimidines and purines. This unique bonding pattern is what unites two DNA strands together. The structure formed from these precise chemical interactions is termed a double helix.
The twisted shape of DNA is what led researches to coin the term double helix. A molecule of DNA is two single strands joined together by hydrogen bonds. A single strand of DNA is likened to a ladder that has been cut down the middle, resulting in two halves.
One strand complements the other in a way that is also related to chemical structure. The component nucleotides make the rungs of the ladder. The nucleotides in the first strand of DNA, the left side of the ladder, pair with nucleotides in the second DNA strand or the right side of the ladder. Together, the two DNA strands unite to form what looks like one single ladder.
For genes to properly function, the nucleotides must pair correctly. They do this by adhering to a strict set of base-pairing rules that were discovered by pioneers in the science of genetics, James Watson and Francis Crick. Base-pairing rules dictate that a purine always pairs with a pyrimidine. In other words, adenine always pairs with thymine and cytosine always pairs with guanine.
The hydrogen bonds formed between nucleotide pairs are important to the structure of DNA. These weak bonds, along with complex bonding among other molecular elements are what give DNA its twisted appearance. This particular shape is why DNA is aptly named a double helix. - 16747
About the Author:
RJ Sullivan manages several profitable online businesses and is a accomplished editor and writer. Ms. Sullivan also writes for In the Gno, a blog dedicated to demystifying the science of genetics in an interesting and easy-to-understand manner. Visit In the Gno to learn more about genetics and DNA.
