Telomeres and Their Structure
8 Questions
4 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 function of telomeres?

  • To protect the ends of linear chromosomes (correct)
  • To assist in protein synthesis
  • To enhance the mutation rate of DNA
  • To facilitate replication of RNA molecules

    • How do telomeres relate to the aging process?

  • They increase the lifespan of all cell types
  • Their length is inversely related to cell division frequency (correct)
  • They lengthen with each cell division
  • They are unaffected by cellular division

    • Which sequence best describes telomeric DNA in humans?

  • Repeated noncoding hexameric sequences (correct)
  • Short single-stranded regions only
  • Alternating sequences of coding regions
  • Linear coding sequences for proteins

    • What occurs to telomeres in normal somatic cells after multiple divisions?

    <p>They gradually shorten until senescence occurs</p> Signup and view all the answers

    What is the role of telomerase in stem cells and cancer cells?

    <p>To extend the length of telomeres, preventing senescence</p> Signup and view all the answers

    What does the end replication problem primarily affect?

    <p>The replication of linear DNA molecules in eukaryotic cells</p> Signup and view all the answers

    What is the structural characteristic of telomeres?

    <p>They have a loop structure stabilized by proteins</p> Signup and view all the answers

    What components make up the telomerase enzyme?

    <p>A protein and a short RNA template</p> Signup and view all the answers

    Study Notes

    Telomeres

    • Telomeres are protective caps at the ends of linear chromosomes, composed of non-coding DNA and proteins
    • They act like mitotic clocks – their length inversely correlates with cell divisions
    • Telomeres prevent chromosome degradation by nucleases
    • They allow repair systems to distinguish chromosome ends from DNA breaks

    ### Telomere Structure

    • Human telomeric DNA is made up of multiple repeats of the hexameric sequence AG3T2
    • This sequence is base-paired to a complementary region of Cs and As
    • The GT-rich strand is longer than the CA complement, leaving a single-stranded region of a few hundred nucleotides
    • This single-stranded region forms a loop structure stabilized by protein

    ### End Replication Problem

    • Replicating linear DNA ends poses a challenge in eukaryotic cells
    • Removal of the RNA primer from the 5’ end leaves a gap that cannot be filled
    • As cells divide, telomeres progressively shorten
    • Shortened telomeres contribute to cellular senescence (cell aging)

    Telomerase and Telomere Maintenance

    • Germ cells, stem cells, and cancer cells maintain telomere length through the action of telomerase
    • Telomerase is a ribonucleoprotein containing a reverse transcriptase protein and a template RNA
    • The RNA template base-pairs with the GT-rich single-stranded 3' end of telomeric DNA, allowing telomere extension

    Studying That Suits You

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

    Quiz Team

    Related Documents

    BMS 141 Lecture 4: Telomere & Telomerase (Fall 2024) PDF

    Description

    This quiz delves into the fascinating world of telomeres, the protective caps at the ends of chromosomes. Explore their structure, function, and the end replication problem that leads to cellular aging. Test your knowledge on how telomeres contribute to genomic stability.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser