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Difficulty: MediumGene Mutations and Chromosomal Aberrations

Match each type of gene mutation or chromosomal aberration on the left with its corresponding description on the right.

  • Substitution mutationReplacement of a single nucleotide base with another within the DNA sequence.
  • Frameshift mutationAddition or deletion of nucleotides that alters the triplet reading frame of the genetic code.
  • AneuploidyGain or loss of specific individual chromosomes resulting in conditions such as 2n+12n+1 or 2n−12n-1.
  • PolyploidyPossession of more than two complete sets of chromosomes, such as 3n3n or 4n4n.

Answer

Substitution mutation matches replacement of a single nucleotide base; Frameshift mutation matches addition or deletion altering the reading frame; Aneuploidy matches gain or loss of specific individual chromosomes (2n+12n+1 or 2n−12n-1); Polyploidy matches possession of extra complete chromosome sets (3n3n or 4n4n).
Substitution mutation corresponds to swapping a single nucleotide base for another. Frameshift mutation occurs when additions or deletions of nucleotides shift the triplet codon reading sequence. Aneuploidy describes the loss or gain of individual chromosomes, while polyploidy describes organisms having additional full sets of chromosomes.

Step-by-Step Solution

1
Distinguish between gene mutations and numerical chromosomal aberrations.
Substitution and frameshift are point gene mutations, while aneuploidy and polyploidy involve changes in chromosome number.
Gene mutations affect nucleotide sequences within a gene, whereas numerical aberrations alter chromosome counts.
2
Identify the mechanisms of point mutations.
Substitution replaces a single base, whereas frameshift adds or deletes bases shifting downstream codons.
Codons are read in triplets, so non-multiple-of-three insertions or deletions disrupt all subsequent amino acid translation.
3
Distinguish between aneuploidy and polyploidy.
Aneuploidy affects individual chromosome counts (2n±12n \pm 1), whereas polyploidy involves entire extra sets of chromosomes (3n,4n3n, 4n).
Non-disjunction of a single chromosome pair causes aneuploidy, whereas failure of spindle formation during total cell division leads to polyploidy.

Key Concept

Gene Mutations vs Chromosomal Numerical Aberrations
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Topics

Gene Mutations and Chromosomal Aberrations

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