Textbook Question
Why do the genomes of eukaryotes, such as Drosophila, need to have multiple origins of replication, whereas bacterial genomes, such as that of E. coli, have only a single origin?
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Ch. 7 - DNA Structure and Replication
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 7, Problem 26a
Telomeres are found at the ends of eukaryotic chromosomes. What is the sequence composition of telomeres?
Verified step by step guidance1
Understand that telomeres are repetitive DNA sequences located at the ends of eukaryotic chromosomes, serving to protect the chromosome from degradation and fusion with other chromosomes.
Learn that the sequence composition of telomeres is highly conserved across many eukaryotic organisms. In humans and other vertebrates, the telomeric sequence is typically a repeated hexanucleotide motif.
Recognize that the specific sequence in humans is represented as , where 'n' indicates the number of repeats.
Understand that telomerase, an enzyme, is responsible for adding these repetitive sequences to the ends of chromosomes, ensuring their maintenance and stability during cell division.
Explore how telomeres play a critical role in cellular aging and genome stability, as their shortening over time is associated with aging and certain diseases.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Telomere Structure
Telomeres are repetitive nucleotide sequences located at the ends of eukaryotic chromosomes. They consist primarily of tandem repeats of a specific DNA sequence, typically rich in guanine (G) and cytosine (C), which helps protect the chromosome from degradation and prevents the loss of essential genetic information during DNA replication.
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Telomeres and Telomerase
Function of Telomeres
The primary function of telomeres is to maintain chromosomal stability by preventing the ends of chromosomes from fusing with each other or being recognized as damaged DNA. As cells divide, telomeres shorten, which is associated with cellular aging and limits the number of times a cell can divide, a phenomenon known as the Hayflick limit.
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Telomerase Enzyme
Telomerase is an enzyme that adds nucleotide sequences to the ends of telomeres, counteracting their shortening during cell division. This enzyme is particularly active in stem cells and cancer cells, allowing them to maintain telomere length and proliferate indefinitely, which is a key factor in tumorigenesis.
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Related Practice
Textbook Question
Bloom syndrome (OMIM 210900) is an autosomal recessive disorder caused by mutation of a DNA helicase. Among the principal symptoms of the disease are chromosome instability and a propensity to develop cancer. Explain these symptoms on the basis of the helicase mutation.
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Textbook Question
How does rolling circle replication differ from bidirectional replication?
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Textbook Question
Telomeres are found at the ends of eukaryotic chromosomes. How does telomerase assemble telomeres?
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Textbook Question
Telomeres are found at the ends of eukaryotic chromosomes. What is the functional role of telomeres?
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Textbook Question
Telomeres are found at the ends of eukaryotic chromosomes. Why is telomerase usually active in germ-line cells but not in somatic cells?
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