nucleic acid

(noun)

Any acidic, chainlike biological macromolecule consisting of repeating units of phosphoric acid, sugar, and purine and pyrimidine bases; they are involved in the preservation, replication, and expression of hereditary information in every living cell.

Related Terms

Examples of nucleic acid in the following topics:

  • Inhibiting Nucleic Acid Synthesis

    • Antimicrobial drugs inhibit nucleic acid synthesis through differences in prokaryotic and eukaryotic enzymes.
    • Antimicrobial drugs can target nucleic acid (either RNA or DNA) synthesis.
    • The antimicrobial actions of these agents are a result of differences in prokaryotic and eukaryotic enzymes involved in nucleic acid synthesis.
    • State the steps where inhibitors of nucleic acid synthesis can exert their function

  • Viral Size

    • The nucleic acid carries the virus's genome—its collection of genes—and may consist of either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
    • The protein capsid provides protection for the nucleic acid and may contain enzymes that enable the virus to enter its appropriate host cell.
    • The amount and arrangement of the proteins and nucleic acid of viruses determine their size and shape.
    • The protein and nucleic acid constituents have properties unique for each class of virus; when assembled, they determine the size and shape of the virus for that specific class.
    • Shapes of viruses are predominantly of two kinds: rods, or filaments, so called because of the linear array of the nucleic acid and the protein subunits; and spheres, which are actually 20-sided (icosahedral) polygons.

  • Nature of the Virion

    • A virion is an entire virus particle consisting of an outer protein shell called a capsid and an inner core of nucleic acid (either ribonucleic or deoxyribonucleic acid—RNA or DNA).
    • The nucleic acid is densely coiled within.
    • Other virions have a capsid consisting of an irregular number of surface spikes, with the nucleic acid loosely coiled within.
    • Virions of most plant viruses are rod-shaped; the capsid is a naked cylinder (lacking a fatty membrane) within which lies a straight or helical rod of nucleic acid.
    • Proteins associated with nucleic acid are known as nucleoproteins, and the association of viral capsid proteins with viral nucleic acid is called a nucleocapsid.

  • Identification of Microbes Based on Molecular Genetics

    • Modern nucleic acid-based microbial detection methods make it possible to identify microbes that are associated with a disease.
    • Modern nucleic acid-based microbial detection methods make it possible to identify microbes that are associated with a disease.
    • A nucleic acid sequence belonging to a putative pathogen should be present in most cases of an infectious disease.
    • Fewer, or no, copies of the pathogen-associated nucleic acid sequences should occur in hosts or tissues without disease.
    • With resolution of the disease, the copy number of pathogen-associated nucleic acid sequences should decrease or become undetectable.

  • Basic Techniques to Manipulate Genetic Material (DNA and RNA)

    • To understand the basic techniques used to work with nucleic acids, remember that nucleic acids are macromolecules made of nucleotides (a sugar, a phosphate, and a nitrogenous base) linked by phosphodiester bonds.
    • To study or manipulate nucleic acids, the DNA or RNA must first be isolated or extracted from the cells.
    • Nucleic acids in a gel matrix can be observed using various fluorescent or colored dyes.
    • Nucleic acid samples, such as fragmented genomic DNA and RNA extracts, can be probed for the presence of certain sequences.
    • Gel electrophoresis separates the nucleic acid fragments according to their size.

  • Elements of Life

    • In such a reducing atmosphere, electrical activity can catalyze the creation of certain basic small molecules (monomers) of life, like amino acids.
    • Since replication is accomplished in modern cells through the cooperative action of proteins and nucleic acids, the major schools of thought about how the process originated can be broadly classified as "proteins first" and "nucleic acids first. " The principal thrust of the "nucleic acids first" argument is as follows:
    • Synthesized proteins might then out-compete ribozymes in catalytic ability, therefore becoming the dominant biopolymer, relegating nucleic acids to their modern use as a carrier of genomic information.
    • Using this apparatus, and using conditions thought to approximate the conditions on pre-biotic earth, they were able to catalyze the molecules of life like amino acids.

  • The Primary Structure of DNA

    • A few years later, Miescher separated nuclein into protein and nucleic acid components.
    • Unlike proteins, nucleic acids contained no sulfur.
    • To reflect the unusual sugar component, chromosomal nucleic acids are called deoxyribonucleic acids, abbreviated DNA.
    • Analogous nucleic acids in which the sugar component is ribose are termed ribonucleic acids, abbreviated RNA.
    • The acidic character of the nucleic acids were moiety attributed to the phosphoric acid moiety.

  • Dehydration Synthesis

    • Three of the four major classes of biological macromolecules (complex carbohydrates, nucleic acids, and proteins), are composed of monomers that join together via dehydration synthesis reactions.
    • Complex carbohydrates are formed from monosaccharides, nucleic acids are formed from mononucleotides, and proteins are formed from amino acids.
    • In nucleic acids and proteins, the location and stereochemistry of the covalent linkages connecting the monomers do not vary from molecule to molecule, but instead the multiple kinds of monomers (five different monomers in nucleic acids, A, G, C, T, and U mononucleotides; 21 different amino acids monomers in proteins) are combined in a huge variety of sequences.
    • Each protein or nucleic acid with a different sequence is a different molecule with different properties.
    • In the dehydration synthesis reaction between two amino acids, with are ionized in aqueous environments like the cell, an oxygen from the first amino acid is combined with two hydrogens from the second amino acid, creating a covalent bond that links the two monomers together to form a dipeptide.

  • Inhibiting Essential Metabolite Synthesis

    • The first, antifolates impair the function of folic acid leading to disruption in the production of DNA and RNA.
    • For example, methotrexate is a folic acid analogue, and owing to structural similarity with folic acid, methotrexate binds and inhibits the enzyme dihydrofolate reductase, and thus prevents the formation of tetrahydrofolate.
    • Three nucleobases found in nucleic acids, cytosine (C), thymine (T), and uracil (U), are pyrimidine derivatives and the pyrimidine analogues disrupt their formation and consequently disrupt DNA and RNA synthesis.
    • Two of the four bases in nucleic acids, adenine and guanine, are purines.
    • Purine analogues disrupt nucleic acid production.

  • Nitrogenous Waste in Birds and Reptiles: Uric Acid

    • Of the four major macromolecules in biological systems, both proteins and nucleic acids contain nitrogen.
    • In contrast, mammals (including humans) produce urea from ammonia; however, they also form some uric acid during the breakdown of nucleic acids.
    • Uric acid is a compound similar to purines found in nucleic acids.
    • Uric acid is also less toxic than ammonia or urea.
    • Uric acid is released in hypoxic conditions.