Chromosomal Translocations and Mutations
43 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 a chromosomal translocation?

  • A mutation where nucleotides are deleted.
  • A DNA replication error that leads to a change in the sequence.
  • A mutation where a piece of a chromosome breaks off and attaches to another chromosome. (correct)
  • A type of induced mutation caused by UV light.

    • Spontaneous mutations are always caused by environmental factors.

    False

    What is depurination?

    The loss of a purine base (adenine or guanine) from the DNA sequence.

    Induced mutations can be caused by factors such as __________ and UV light.

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

    Match the types of mutations to their descriptions:

    <p>Spontaneous mutations = Caused by errors during DNA replication or repair Induced mutations = Caused by external factors like chemicals and UV light Trinucleotide expansions = Repeated sequences of three nucleotides leading to abnormal proteins Chromosomal translocations = Segments of chromosomes attaching to non-homologous chromosomes</p> Signup and view all the answers

    What mutation is associated with Huntington's Disease?

    <p>CAG repeat number of 40 or more</p> Signup and view all the answers

    X-rays can cause double-strand breaks in DNA.

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

    Deamination results in the formation of __________ from a cytosine base.

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

    Which DNA repair mechanism is considered error-free?

    <p>Homologous Recombination (HR)</p> Signup and view all the answers

    MSH2 is involved in the repair of single-strand breaks in DNA.

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

    What genetic disorder is associated with mutations in the ATM gene?

    <p>Ataxia Telangiectasia</p> Signup and view all the answers

    The process of _______________ involves direct ligation of broken DNA ends without needing a template.

    <p>Non-Homologous End Joining</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>MSH2 = Involved in mismatch repair NHEJ = A quick and error-prone repair method HR = Uses the unmutated copy as a template ATM = Initiates repair of double-strand breaks</p> Signup and view all the answers

    What is the first level of DNA packaging?

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

    Euchromatin is highly condensed and found in areas with low gene expression.

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

    What role do acetyl groups play in histone acetylation?

    <p>They eliminate the positive charge of histones, allowing DNA to open up.</p> Signup and view all the answers

    The structures formed by the coiling of nucleosomes are called __________.

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

    Match the following types of chromatin with their characteristics:

    <p>Heterochromatin = Highly condensed, structural function Euchromatin = Less condensed, high gene expression</p> Signup and view all the answers

    What effect does the addition of acetyl groups to histones have on gene expression?

    <p>It opens DNA for gene expression</p> Signup and view all the answers

    Histones are responsible for packaging DNA into a compact form.

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

    What determines whether DNA remains compact or opens up?

    <p>The acetylation of histones.</p> Signup and view all the answers

    The diameter of the nucleus is approximately __________ microns.

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

    Which of the following is characterized as being highly condensed?

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

    Which sugar is found in RNA?

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

    RNA contains thymine as one of its bases.

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

    What is the primary function of mRNA?

    <p>carries genetic information from DNA to the ribosome for protein synthesis</p> Signup and view all the answers

    In DNA replication, the enzyme responsible for unwinding the DNA double helix is called ___.

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

    Match the type of RNA with its function:

    <p>mRNA = carries genetic information tRNA = brings amino acids rRNA = makes up ribosome snRNA = involved in RNA splicing</p> Signup and view all the answers

    Which of the following accurately represents a base pairing in RNA?

    <p>Adenine pairs with Uracil</p> Signup and view all the answers

    The leading strand in DNA replication is synthesized in short segments.

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

    What are the three stages of DNA replication?

    <p>initiation, elongation, termination</p> Signup and view all the answers

    The strand of DNA that is synthesized in short segments is called the ___.

    <p>lagging strand</p> Signup and view all the answers

    Match the components of DNA replication to their functions:

    <p>ORC = recruits enzymes for replication MCM = helps unwind DNA DNA polymerase = synthesizes new DNA strands Helicase = unwinds the double helix</p> Signup and view all the answers

    What is the primary function of helicase during DNA replication?

    <p>Unwind the DNA double helix</p> Signup and view all the answers

    The leading strand is synthesized in the opposite direction to the lagging strand.

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

    Name one enzyme involved in synthesizing the leading strand.

    <p>DNA polymerase epsilon</p> Signup and view all the answers

    During DNA replication, the ____ strand is synthesized continuously.

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

    What is the role of topoisomerase in DNA replication?

    <p>Relieve torsional stress on the DNA molecule</p> Signup and view all the answers

    The lagging strand is synthesized in a continuous manner.

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

    What are the two replication forks involved in DNA replication?

    <p>Fork 1 and Fork 2</p> Signup and view all the answers

    The lagging strand is synthesized in short, discontinuous ____.

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

    Match the following enzymes with their primary functions:

    <p>Helicase = Unwinds the DNA double helix DNA polymerase epsilon = Synthesizes the leading strand DNA polymerase alpha and delta = Synthesize the lagging strand Topoisomerase = Relieves torsional stress</p> Signup and view all the answers

    Which of the following statements about DNA replication is correct?

    <p>DNA replication involves both leading and lagging strands.</p> Signup and view all the answers

    Study Notes

    Chromosomal Translocations

    • A mutation where a segment of a chromosome detaches and reattaches to another chromosome.

    Spontaneous Mutations

    • Mutations occurring naturally, often due to errors during DNA replication or repair.
    • Depurination: Loss of a purine base (adenine or guanine) from DNA.
    • Deamination: Removal of an amino group from a cytosine base, producing uracil.

    Induced Mutations

    • Caused by external agents, altering DNA sequences:
      • Chemicals: Various chemicals can trigger mutations.
      • Ultraviolet (UV) Light: Induces the formation of pyrimidine dimers.
      • X-rays: Can create double-strand breaks in DNA.

    Trinucleotide Expansions

    • A specific type of mutation where a sequence of three nucleotides is repeatedly expanded, potentially leading to abnormal protein function.
    • Example: Huntington's Disease
      • Normal repeat of CAG is 28 or fewer, pathological occurs with 40 or more repeats.

    DNA Packaging

    • DNA must be condensed to fit into the cell nucleus, which is significantly smaller than the total length of DNA (approximately 2 meters).
    • Levels of DNA Packaging:
      • Histones: Proteins that form nucleosomes, the basic unit of DNA packing.
      • Nucleosomes: DNA wrapped around histones.
      • Solenoids: Further coiling of nucleosomes.

    Control of DNA Packaging

    • Histone Acetylation:
      • Adding acetyl groups to histone lysines reduces positive charge, allowing genes to be expressed.
      • Without acetyl groups, DNA remains compact and gene expression is restricted.

    Chromatin Structure

    • Heterochromatin: Highly condensed, located at telomeres and centromeres; serves structural roles.
    • Euchromatin: Less condensed, found in gene-rich areas with active transcription.

    RNA Structure

    • RNA (ribonucleic acid) plays a vital role in gene expression and has notable differences from DNA:
      • Contains ribose sugar with a hydroxyl group at the 2' carbon.
      • Uses uracil in place of thymine.
      • Possesses a negatively charged phosphodiester backbone.

    Types of RNA

    • mRNA: Transmits genetic information from DNA to ribosomes for protein synthesis.
    • tRNA: Brings amino acids to ribosomes during protein synthesis.
    • rRNA: Forms a significant component of ribosomes, crucial for protein synthesis.

    DNA Replication

    • Occurs in three stages:
      • Initiation: Begins at specific DNA sequences, involves the Origin of Replication Complex (ORC) and MCM (Mini-Chromosome Maintenance) for unwinding.
      • Elongation: Involves helicase unwinding the DNA, and DNA polymerases synthesizing new strands (leading continuously, lagging in fragments).
      • Termination: Involves the replication fork where DNA is actively copied.

    Enzymes in DNA Replication

    • Helicase: Unwinds the DNA double helix.
    • DNA Polymerase: Synthesizes new DNA strands (epsilon for leading, alpha and delta for lagging).
    • Topoisomerase: Relieves torsional stress by cutting and unwinding DNA during replication.

    DNA Repair Mechanisms

    • Mismatch Repair: Vital for maintaining genomic integrity, mutations in MSH2 and MLH1 are linked to Lynch syndrome, increasing cancer risk.
    • Double-Strand Break Repair:
      • Non-Homologous End Joining (NHEJ): Quick repair that doesn’t require a template, can introduce mutations.
      • Homologous Recombination (HR): Accurate repair using a homologous template, considered error-free.

    Role of ATM Gene

    • Critical for initiating repair processes for double-strand breaks via both NHEJ and HR.
    • Ataxia Telangiectasia: Genetic disorder from ATM mutations, leading to increased mutation accumulation and cancer risk.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Overview of DNA Structure and Replication PDF

    Description

    Explore the fascinating world of chromosomal translocations and spontaneous mutations in this quiz. Learn about the processes that lead to changes in DNA, such as depurination and deamination, and understand their implications. Test your knowledge on these fundamental genetic concepts.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser