Category: Q

  • Quince


    The quince, a relative of the apple and pear but too bitter to be eaten uncooked, derives its name from Cydonia, a port on the coast of Crete now known as Khania. Because the fruit was exported from Cydonia, the ancient Greeks called it melon Kudonion, meaning Cydonian apple. This name entered Latin as cydoneum,…

  • Quignon

    To my chagrin, using the term bread-bum to refer to the end-slice of a loaf of bread is not appropriate at most formal dinner parties. Fortunately, another word exists for this crusty and much sought after part of the loaf: quignon. This useful word derives through French from the Latin cuneolus, meaning little coin, the…

  • Quesadilla


    In Spanish, the word queso means cheese, and the endings ilia and illo are suffixes used to form the feminine or masculine diminutives of a word, just as French and English often use the diminutive ette, as in kitchenette. Thus, quesadilla, the name of a turnover filled with cheese, means little cheese. The ilia diminutive…

  • Quick-stop

    The term used to describe how DNA mutants of Escherichia coli cease replication immediately when the temperature is increased to 42°C (108°F).  

  • Quaternary structure

    The three-dimensional structure of an oligomeric protein; particularly the manner in which the subunit chains fit together.  

  • Quantitative trait loci (QTL)

    Individual specific DNA sequences that are related to known traits (e.g., litter size in animals, egg production in birds, yield in crop plants.)  

  • Quantitative structure-activity relationship (QSAR)

    A computer modeling technique that enables researchers (e.g., drug development chemists) to predict the likely activity (e.g., effect on tissue) of a new compound before that compound is actually created. QSAR is based on decades of research investigating the impact on “activity” of the chemical structures of thousands of thoroughly studied molecules.  

  • Q-beta replicase technique

    An RNA assay (test) that “amplifies RNA probes” that a researcher is seeking. For instance, by using the Q-beta replicase technique to assay for the presence of RNA that is specific to the AIDS virus, it is possible to detect an AIDS infection in a patient’s blood sample long before that infection has progressed to…

  • Q-beta replicase

    A viral RNA polymerase secreted by a bacteriophage that infects Escherichia coli bacteria. Q-beta replicase can copy a naturally occurring RNA (molecule) sequence (e.g., from bacteria, viruses, fungi, or tumor cells) at a geometric (i.e., very fast) rate.  

  • Quickly frozen

    Freezing of food using a system such as blast freezing for a sufficient length of time to freeze to quickly to the center of the food with virtually no deterioration.