def cog2str(cog):
    """
    Get the full description for a COG category letter

    Parameters
    ----------
    cog : str
        COG category letter

    Returns
    -------
    str
        Description of COG category
    """

    cog_dict = {
        "A": "RNA processing and modification",
        "B": "Chromatin structure and dynamics",
        "C": "Energy production and conversion",
        "D": "Cell cycle control, cell division, chromosome partitioning",
        "E": "Amino acid transport and metabolism",
        "F": "Nucleotide transport and metabolism",
        "G": "Carbohydrate transport and metabolism",
        "H": "Coenzyme transport and metabolism",
        "I": "Lipid transport and metabolism",
        "J": "Translation, ribosomal structure and biogenesis",
        "K": "Transcription",
        "L": "Replication, recombination and repair",
        "M": "Cell wall/membrane/envelope biogenesis",
        "N": "Cell motility",
        "O": "Post-translational modification, protein turnover, and chaperones",
        "P": "Inorganic ion transport and metabolism",
        "Q": "Secondary metabolites biosynthesis, transport, and catabolism",
        "R": "General function prediction only",
        "S": "Function unknown",
        "T": "Signal transduction mechanisms",
        "U": "Intracellular trafficking, secretion, and vesicular transport",
        "V": "Defense mechanisms",
        "W": "Extracellular structures",
        "X": "No COG annotation",
        "Y": "Nuclear structure",
        "Z": "Cytoskeleton",
    }

    return cog_dict[cog]