Genomics: Organization of the Human Genome
42 Questions
0 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 approximate number of genes in the human genome?

  • 10,000
  • 23,000 (correct)
  • 30,000
  • 50,000

    • What is the C-value of the human genome?

  • 1.2 gpb
  • 3.2 gpb (correct)
  • 2.8 gpb
  • 4.5 gpb

    • What is the result of gene duplication and evolutionary divergence?

  • Gene expression
  • Gene families (correct)
  • Gene mutation
  • Gene deletion

    • What is the approximate number of nucleotides in the human genome?

    <p>34.5 million</p> Signup and view all the answers

    What is the approximate number of amino acids in a protein?

    <p>500</p> Signup and view all the answers

    What is the C-value of bacteria?

    <p>x Mega bases</p> Signup and view all the answers

    What is the result of gene duplication?

    <p>Gene families</p> Signup and view all the answers

    What is the approximate number of genes in a gene family?

    <p>5-30</p> Signup and view all the answers

    What is the effect of a negative alteration?

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

    What type of mutation affects only the individual?

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

    What is the result of a regulatory gene mutation?

    <p>Alteration of activity, malformations and tumors</p> Signup and view all the answers

    What is the effect of a germline mutation on offspring?

    <p>Affects all cells of the descendant with the mutation</p> Signup and view all the answers

    What type of mutation occurs during embryonic development?

    <p>Genetic mosaic</p> Signup and view all the answers

    What can occur as a result of errors in replication and repair?

    <p>All of the above</p> Signup and view all the answers

    What is the primary cause of thymine dimers?

    <p>UV light</p> Signup and view all the answers

    What is the role of photoreactivation in the context of thymine dimers?

    <p>It repairs thymine dimers</p> Signup and view all the answers

    What is the result of thymine dimers on DNA?

    <p>Mutations in DNA</p> Signup and view all the answers

    What type of light is involved in the formation of thymine dimers?

    <p>UV light</p> Signup and view all the answers

    What is the relationship between thymine dimers and mutations?

    <p>Thymine dimers cause mutations</p> Signup and view all the answers

    What is the process by which thymine dimers are repaired?

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

    What type of mutation occurs when there is a 'slip of the two propellers' during DNA replication?

    <p>Phase change mutation</p> Signup and view all the answers

    What is the result of a 'slip of the two propellers' during DNA replication?

    <p>Repetition of a sequence</p> Signup and view all the answers

    What type of radiation can cause damage to DNA structure?

    <p>Ionizing radiation</p> Signup and view all the answers

    What is the consequence of a DNA sequence being broken off and re-ligated?

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

    What type of mutation occurs when a sequence is duplicated and then diverges?

    <p>Gene duplication and evolutionary divergence</p> Signup and view all the answers

    What is the result of an insertion?

    <p>A nucleotide is added</p> Signup and view all the answers

    What type of mutation occurs when a sequence is moved from one location to another?

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

    What is the result of a deletion?

    <p>A nucleotide is deleted</p> Signup and view all the answers

    Where in the gene sequence can mutations occur that affect translation efficiency?

    <p>5'UTR</p> Signup and view all the answers

    What is the range of natural gene mutation rates?

    <p>10-5– 10-7</p> Signup and view all the answers

    Which genetic disorder is associated with an elevated mutation rate?

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

    What type of genetic sequence variation has no clinical relevance?

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

    Where do disease-causing mutations occur?

    <p>In the gene sequence</p> Signup and view all the answers

    What is the consequence of a mutation in the 3'UTR region?

    <p>Myotonic Dystrophy</p> Signup and view all the answers

    What is the consequence of an intron point deletion mutation?

    <p>The intron sequence is added to the polypeptide</p> Signup and view all the answers

    What is the role of splicing-site mutations?

    <p>They affect the intron removal process</p> Signup and view all the answers

    What is the result of a mutation in control elements?

    <p>The promoter sequence is altered, affecting gene expression rate</p> Signup and view all the answers

    What is the consequence of an intron not being removed from the mRNA?

    <p>The polypeptide has a very different sequence</p> Signup and view all the answers

    What is the role of the promoter sequence?

    <p>It is the binding site for RNA polymerase</p> Signup and view all the answers

    What is the result of a mutation in the intron sequence?

    <p>The intron sequence is added to the polypeptide</p> Signup and view all the answers

    What is the consequence of a mutation in the 5' UTR sequence?

    <p>No consequence, as it is a non-coding region</p> Signup and view all the answers

    What is the role of RNA polymerase in gene expression?

    <p>It is involved in transcription initiation</p> Signup and view all the answers

    Study Notes

    Genome Organization

    • The amount of DNA per haploid genome of a species is represented by the C-value.
    • In somatic cells, the C-value is 2C in G1 phase and 4C in G2 phase.
    • The human C-value is 3.2 gpb, which is equivalent to 3.2 x 10^9 bp.

    Gene Content

    • The human genome contains approximately 23,000 genes.
    • On average, one protein is composed of about 500 amino acids.
    • If each gene encoded only one protein, the total number of base pairs required would be approximately 34,500,000 bp.

    Gene Families

    • Gene families arise from gene duplication and evolutionary divergence.
    • Members of a gene family have a close resemblance, similar functions, but may have different roles.
    • Examples of gene families include:
      • Actins (5-30 genes)
      • Variable region of the Ig (500 genes)
      • Hemoglobin genes (e.g. HBB, HBD, HBG1, HBG2, HBA1, HBA2, HBM, HBQ1)

    Types of Mutations

    • Positive mutations: selection
    • Neutral mutations: genetic variability between individuals
    • Negative mutations: damage

    Effects of Mutations on Cells

    • Somatic mutations: affect the individual
    • Germinal mutations: affect offspring
    • Genetic mosaic: mixture of genetically different cells in an individual or offspring

    Consequences of Mutations

    Gene Structure

    • Substitutions: errors in replication or repair
    • Deletions: loss of base pairs

    Ultraviolet Light

    • Produces thymine dimers
    • Thymine dimers: two thymine molecules bonded together
    • Photoreactivation: repair of thymine dimers using visible light

    Replication Errors

    • Phase change mutations: repeated sequences
    • Slip of the two propellers: errors in replication

    Mutations Affecting DNA Structure

    • Inversions: reversal of DNA segments
    • Translocations: exchange of DNA segments between non-homologous chromosomes
    • Insertions: addition of DNA segments

    Agents Damaging DNA Structure

    • Ionizing radiation

    Consequences of Mutations

    Gene Segments

    • Changes in gene segments: can affect gene function

    Intron Point Deletions

    • Presence of intron sequence in mRNA: addition of corresponding stretch in polypeptide
    • Splicing-site mutations: affect splicing, leading to incorrect removal of introns

    Mutations in Control Elements

    • Modulators of gene expression: affect transcription rate
    • Promoter mutations: affect gene expression
    • Examples: Lactase Persistence, Hemophilia B, Myotonic Dystrophy

    Mutagenesis

    • Natural gene mutation rates: 10-5– 10-7
    • Elevated mutation rates in certain genes: Achondroplasia, Duchenne Muscular Dystrophy, X-fragile syndrome
    • Genetic sequence: normal variants (polymorphisms), disease-causing mutations

    Studying That Suits You

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

    Quiz Team

    Description

    Explore the organization of the human genome, including genes and non-coding sequences. Learn about the differences in genome size between viruses, bacteria, and eukaryotes. Understand the concept of C-value and how it relates to the amount of DNA per cell.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser