Chromosomal Aberrations Quiz
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Questions and Answers

What is the primary consequence of unbalanced chromosomal aberrations?

  • Developmental rates increase
  • Chromosomes miss genetic information (correct)
  • Normal genetic information is retained
  • Structural integrity is enhanced

What type of structural aberration involves the loss of a chromosomal segment resulting in a looped structure?

  • Inversion
  • Deletion (correct)
  • Duplication
  • Translocation

Which type of chromosomal aberration results in two copies of the same gene on a chromosome?

  • Translocation
  • Duplication (correct)
  • Inversion
  • Deletion

Which of the following describes a Robertsonian translocation?

<p>Fusion of long arms of acrocentric chromosomes (C)</p> Signup and view all the answers

What defines a pericentric inversion in structural aberrations?

<p>Breaks occur on both sides of the centromere (C)</p> Signup and view all the answers

In isochromosomes, what is the characteristic feature of the chromatids?

<p>They possess two long arms or two short arms (B)</p> Signup and view all the answers

What is a common result of structural chromosomal aberrations like Cri du chat syndrome?

<p>Deletion of genetic material (B)</p> Signup and view all the answers

In reciprocal translocation, what is a key feature?

<p>No genes are lost or added (C)</p> Signup and view all the answers

What is the potential risk for a child when a parent carries a translocation involving chromosome 21?

<p>Risk of having a child with Down syndrome can rise significantly (D)</p> Signup and view all the answers

Flashcards

Chromosomal Aberrations

Deviations from normal chromosome number or structure, often causing developmental issues.

Structural Aberrations

Mutations affecting the chromosome's structure, not the total number.

Deletion (Chromosomal)

Loss of a chromosome segment.

Duplication (Chromosomal)

Having extra copies of a chromosome segment.

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Inversion (Chromosomal)

Reversal of a chromosome segment.

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Translocation (Chromosomal)

Transfer of a chromosome segment to a non-homologous chromosome.

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Robertsonian Translocation

Fusion of two acrocentric chromosomes, typically 14 and 21.

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Reciprocal Translocation

Exchange of parts between non-homologous chromosomes; balanced.

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Isochromosome

Chromosome with two identical arms (one long, one short).

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Balanced Aberration

Chromosomal abnormality where no genetic material is gained or lost.

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Study Notes

Chromosomal Aberrations

  • Definition: Deviation from normal number or structure of chromosomes
  • Common causes: Congenital disorders and developmental problems
  • Structural aberrations are mutations
    • Balanced aberration: chromosome has normal genetic material
    • Unbalanced aberration: chromosome has missing genetic material

Structural Aberrations Types

  • 1- Break:

    • Result of a break in a chromosome, followed by reunion.
    • Reunion occurs via sticky ends
  • 2- Deletion: Loss of fragmented part of a chromosome

    • Terminal: Loss of a portion at the end of a chromosome
    • Interstitial: Loss of a segment of a chromosome in between two other points
    • Examples: Wolf-Hirschhorn syndrome (deletion of short arm of chromosome 4), Cri-du-chat syndrome (deletion of short arm of chromosome 5)
    • Ring chromosome: loss + reunion in a ring
  • 3- Duplication:

    • Addition of extra piece of homologous chromosome
    • Result of unequal crossing over
    • Two copies of the same gene on a chromosome
  • 4- Inversion:

    • Two breaks in a chromosome, followed by reunion in inverted form
      • Pericentric: Break on both sides of the centromere
      • Paracentric: Break on one side of the centromere
  • 5- Translocation:

    • Transfer of chromosome segment to a non-homologous chromosome
      • Robertsonian translocation (centric fusion): Involves acrocentric chromosomes; fusion of long arms of two acrocentric chromosomes; loss of both short arms (e.g., chromosome 14 and 21, in Down syndrome cases)
        • Risk of having a child with Down syndrome, if a parent is a carrier, can be up to 100%
      • Reciprocal translocation: Exchange of segments between non-homologous chromosomes; balanced (no genes lost or added) example (chromosome 22 and 9).
  • 6- Isochromosomes: Result from a division of a chromosome during anaphase of mitosis.

    • Two non-similar chromatids are created
    • Two non-similar chromosomes form
    • One chromosome will have two long arms and one will have two short arms (e.g., in some cases of submetacentric chromosomes)

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Related Documents

Chromosomal Abberations PDF

Description

Test your knowledge on chromosomal aberrations and their types. This quiz covers definitions, causes, and specific structural aberrations such as deletions and duplications. Ideal for students studying genetics or molecular biology.

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