Question

    The change in chromosome number that involves the entire

    set, either by the loss or gain of one or more entire sets of chromosomes, is referred to as:
    A Nullisomic Correct Answer Incorrect Answer
    B Monosomic Correct Answer Incorrect Answer
    C Trisomic Correct Answer Incorrect Answer
    D Tetrasomic Correct Answer Incorrect Answer
    E all of the above Correct Answer Incorrect Answer

    Solution

    The question is referring to changes in chromosome number that involve variations in the number of sets of chromosomes, which can be classified into different types based on how many copies of each chromosome are present:

    • Nullisomic : Refers to the loss of an entire pair of chromosomes (i.e., two chromosomes are missing from a diploid set). For example, in a nullisomic individual, the organism would have two fewer chromosomes than normal.
    • Monosomic : Refers to the presence of only one chromosome from a pair, instead of two. This means the individual has one chromosome missing from a particular pair (e.g., 2n-1).
    • Trisomic : Refers to the presence of an extra chromosome, i.e., three chromosomes instead of the normal two for a particular chromosome pair (e.g., 2n+1).
    • Tetrasomic : Refers to the presence of four chromosomes from a particular pair, instead of the usual two (e.g., 2n+2).
    Thus, all of these terms ( nullisomic , monosomic , trisomic , tetrasomic ) represent different types of chromosomal abnormalities involving changes in the number of chromosome sets or copies.

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