Mutations
21 Questions
5 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of karyotyping?

To diagnose chromosomal aberrations

What is the role of hypotonic solutions in the karyotyping process?

Swelling, separating, and spreading chromosomes

What is the difference between Q-banding and G-banding techniques?

Q-banding uses fluorescent stain to stain AT-rich regions, while G-banding uses Giemsa stain to stain AT-rich regions

What is the significance of centromere position in karyotyping?

<p>To determine the type of centromere (telocentric, acrocentric, submetacentric, or metacentric)</p> Signup and view all the answers

What is the purpose of ideograms in karyotyping?

<p>To make it easier to interpret and modernize karyotyping</p> Signup and view all the answers

What is the difference between haploid and diploid?

<p>Haploid has a single set of chromosomes, while diploid has two homologous copies of each chromosome</p> Signup and view all the answers

What is polyploidy, and how does it occur?

<p>Polyploidy is having a multiple of the normal haploid number; it occurs when more than one sperm fertilizes an egg</p> Signup and view all the answers

What is aneuploidy, and how does it differ from polyploidy?

<p>Aneuploidy is the presence of an abnormal number of chromosomes; it differs from polyploidy, which involves a multiple of the normal haploid number</p> Signup and view all the answers

What is the result of a failure of the first zygotic division in an embryo?

<p>Tetraploidy</p> Signup and view all the answers

What is the term for the complete loss of a chromosomal pair, and what is the consequence of this condition in early embryogenesis?

<p>Nullisomy; Lethal</p> Signup and view all the answers

What is the genetic condition characterized by the presence of a single X chromosome instead of the usual XX, and what is the name of this condition?

<p>Turner syndrome</p> Signup and view all the answers

What is the method used to rapidly screen for aneuploidy in an embryo before implantation, and at which stage of the cell cycle is it performed?

<p>FISH; Interphase</p> Signup and view all the answers

What is the consequence of a single base substitution that alters the codon to produce an altered amino acid in the protein product?

<p>Missense mutation</p> Signup and view all the answers

What is the consequence of a single base substitution that changes a codon to one of the stop codons, resulting in premature termination of protein synthesis?

<p>Nonsense mutation</p> Signup and view all the answers

What is the term for the insertion or deletion of one or two base pairs, and what is the consequence of this type of mutation?

<p>Indel; Frameshift mutation</p> Signup and view all the answers

What is the consequence of a frameshift mutation, and how can it lead to premature termination of protein synthesis?

<p>Frameshift mutations often create new stop codons, resulting in nonsense mutations.</p> Signup and view all the answers

What is the method used for automated karyotyping, and what advantage does it offer over traditional karyotyping methods?

<p>Spectral karyotyping; Less time-consuming</p> Signup and view all the answers

what is triploidy?

<ul> <li>One complete extra set of chromosomes. happens when more than 1 sperm fertilises the egg</li> </ul> Signup and view all the answers

what is Monosomy?

<ul> <li>When one of the chromosome pair is missing.</li> </ul> Signup and view all the answers

what is Trisomy?

<ul> <li>Addition of extra copy of one chromosome.</li> </ul> Signup and view all the answers

example of genetic condition

<p>turner syndrome where there is only one X instead of XX</p> Signup and view all the answers

Study Notes

Chromosomal Abnormalities

  • Tetraploidy: Failure of the first zygotic division, can be lethal to the embryo.
  • Aneuploidy: Presence of an abnormal number of chromosomes, which can be lethal in very early embryogenesis.

Types of Aneuploidy

  • Nullisomy: Complete loss of a chromosomal pair.
  • Monosomy: When one of the chromosome pair is missing, usually lethal in early embryogenesis.
  • Trisomy: Addition of an extra copy of one chromosome, most are lethal.

Examples of Genetic Conditions

  • Turner syndrome: Presence of 1 X chromosome instead of 2 XX.

Screening Techniques

  • Spectral karyotyping: An automated method that takes less time to perform.
  • FISH (Fluorescence In Situ Hybridization): A rapid process for screening Aneuploidy, can be done in an embryo before implantation.

Mutations

  • Single base substitutions:
    • Missense mutations: Alter the codon to produce an altered amino acid in the protein product, e.g. sickle cell anaemia.
    • Nonsense mutations: Change a codon to one of the stop codons, resulting in premature mRNA termination.
  • Indels: Involving one or two base pairs (or multiples), can cause frameshift mutations, leading to devastating consequences.
  • Frameshifts: Often create new stop codons, resulting in nonsense mutations.

Karyotyping

  • Observed characteristics of the chromosomes of an individual or species to diagnose chromosomal aberrations.
  • Steps involved:
    • Collecting a sample
    • Treating cells with chemicals to arrest in metaphase
    • Swelling, separating, and spreading chromosomes using hypotonic solutions
    • Fixing chromosomes to a slide
    • Staining and viewing banding patterns
    • Arranging by size and location of centromere

Chromosome Stains

  • Q-banding: Fluorescent stain, stains AT-rich regions
  • G-banding: Giemsa stains, identical to Q-banding, stains AT-rich regions
  • R-banding: Reverse Giemsa staining, stains GC-rich regions
  • C-banding: Giemsa stain after DNA denaturation, stains regions near the centromeres

Centromere Position

  • 4 different types of centromere positions:
    • Telocentric: Found on the end of 2 chromosomes
    • Acrocentric: Located close to the end of a chromosome
    • Submetacentric: Not exactly in the center, has a short arm (P arm) and long arm (Q arm)
    • Metacentric: The centromere is located at the center of the 2 chromosomes

Ideograms and Nomenclature

  • Ideograms: Easier to interpret and modern version of karyotyping
  • Nomenclature:
    • Haploid: A single set of chromosomes without homologous pairs
    • Diploid: Having 2 homologous copies of each chromosome
    • Euploidy: Having a multiple of the normal haploid number, e.g. 46, 69
    • Polyploidy: Having multiple sets of chromosomes, e.g. triploidy

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Mutations.docx

Description

Learn about the steps involved in karyotyping, a technique used to diagnose chromosomal aberrations. This process includes treating cells with chemicals, separating and staining chromosomes, and matching banding patterns to identify chromosomal abnormalities.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser