Domanda del libro di testo
DNA polymerase III is the main DNA-synthesizing enzyme in bacteria. Describe how it carries out its role of elongating a strand of DNA.
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Ch. 7 - DNA Structure and Replication
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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TOC.tableOfContents
- 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: 9780135564172Non è quello che usi tu?Cambia libro di testo
Capitolo 7, Problema 11a
There is a problem completing the replication of linear chromosomes at their ends. Describe the problem and identify why telomeres shorten in each replication cycle.
Guida verificata passo dopo passo1
Understand the structure of linear chromosomes: Linear chromosomes have ends called telomeres, which are repetitive DNA sequences that protect the chromosome from degradation and prevent the loss of essential genetic information during replication.
Review the mechanism of DNA replication: DNA polymerase synthesizes new DNA strands in the 5' to 3' direction. However, it requires a primer to initiate synthesis and cannot fully replicate the very ends of the lagging strand due to the removal of the RNA primer.
Explain the end-replication problem: During replication, the RNA primer at the very end of the lagging strand is removed, but DNA polymerase cannot fill in the gap because there is no upstream DNA to provide a starting point. This results in the progressive shortening of the chromosome ends with each replication cycle.
Describe the role of telomeres: Telomeres act as a buffer zone, absorbing the loss of DNA sequences during replication. However, as cells divide repeatedly, telomeres become progressively shorter, eventually leading to cellular senescence or apoptosis when they reach a critically short length.
Introduce the enzyme telomerase: In certain cell types, such as germ cells and stem cells, the enzyme telomerase can extend telomeres by adding repetitive sequences to the ends of chromosomes, counteracting the shortening process and maintaining chromosome integrity.
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Telomeres
Telomeres are repetitive nucleotide sequences located at the ends of linear chromosomes. They protect the chromosome from deterioration or fusion with neighboring chromosomes. Each time a cell divides, a portion of the telomere is not replicated, leading to gradual shortening over successive replication cycles.
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08:38
Telomeres and Telomerase
DNA Replication
DNA replication is the process by which a cell duplicates its DNA before cell division. It involves unwinding the double helix and synthesizing new strands complementary to the original ones. However, due to the nature of DNA polymerase, which cannot fully replicate the ends of linear chromosomes, telomeres are progressively shortened with each replication.
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11:59Steps to DNA Replication
Hayflick Limit
The Hayflick limit refers to the number of times a normal somatic human cell can divide before cell division stops, which is typically around 40-60 divisions. This limit is largely due to telomere shortening, as critically short telomeres trigger cellular senescence or apoptosis, preventing further cell division and contributing to aging.
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07:56Sex-Linked Genes
Pratica correlata
Domanda del libro di testo
Explain how RNA participates in DNA replication.
768
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Domanda del libro di testo
There is a problem completing the replication of linear chromosomes at their ends. What is the function of telomerase, and how does it operate to synthesize telomeres?
423
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Domanda del libro di testo
Consider the sequence 3'-ACGCTACGTC-5'.
What is the total number of noncovalent bonds joining the nucleotides of the complementary strands?
595
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Domanda del libro di testo
Consider the sequence 3'-ACGCTACGTC-5'.
What is the total number of covalent bonds joining the nucleotides in each strand?
943
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Domanda del libro di testo
A sample of double-stranded DNA is found to contain 20% cytosine. Determine the percentage of the three other DNA nucleotides in the sample.
593
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