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.

  • 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.

  • Viral Genomes

    • The type of nucleic acid is irrelevant to the shape of the genome.
    • A viral genome, irrespective of nucleic acid type, is almost always either single-stranded or double-stranded.
    • Single-stranded genomes consist of an unpaired nucleic acid, analogous to one-half of a ladder split down the middle.
    • Double-stranded genomes consist of two complementary paired nucleic acids, analogous to a ladder.

  • 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.

  • DNA Mobility Shifts

    • However, assuming that the protein is capable of binding to the fragment, the lane with protein present will contain another band that represents the larger, less mobile, complex of nucleic acid probe bound to protein, which is "shifted" up on the gel (since it has moved more slowly).
    • Under the correct experimental conditions, the interaction between the DNA and protein is stabilized and the ratio of bound to unbound nucleic acid on the gel reflects the fraction of free and bound probe molecules as the binding reaction enters the gel.
    • If the starting concentrations of protein and probe are known, and if the stoichiometry of the complex is known, the apparent affinity of the protein for the nucleic acid sequence may be determined.
    • This method is referred to as a supershift assay, and is used to unambiguously identify a protein present in the protein-nucleic acid complex.

  • Nucleic Acid Sequencing and rRNA Analysis

    • Nucleic acid sequencing and rRNA analysis consist of comparing nitrogen bases in rRNA.

  • The Pentose Phosphate Shunt

    • These compounds are used in a variety of different biological processes including production of nucleotides and nucleic acids (ribose-5-phosphate), as well as synthesis of aromatic amino acids (erythrose-4-phosphate).
    • NADPH-utilizing pathways, such as fatty acid synthesis, generate NADP+, which stimulates glucose-6-phosphate dehydrogenase to produce more NADPH.
    • It is used in reductive biosynthesis reactions within cells (e.g. fatty acid synthesis).
    • It also produces nucleic acids and erythrose-4-phosphate, used in the synthesis of aromatic amino acids.