Textbook Question
Describe the molecular composition and arrangement of the components in the nucleosome.
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Ch. 12 - DNA Organization in Chromosomes
Klug12th EditionConcepts of Genetics ISBN: 9780135564776
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Table of contents
- Ch. 1 - Introduction to Genetics17
- Ch. 2 - Mitosis and Meiosis36
- Ch. 3 - Mendelian Genetics51
- Ch. 4 - Extensions of Mendelian Genetics74
- Ch. 5 - Chromosome Mapping in Eukaryotes51
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages46
- Ch. 7 - Sex Determination and Sex Chromosomes33
- Ch. 8 - Chromosome Mutations: Variation in Number and Arrangement40
- Ch. 9 - Extranuclear Inheritance31
- Ch. 10 - DNA Structure and Analysis43
- Ch. 11 - DNA Replication and Recombination44
- Ch. 12 - DNA Organization in Chromosomes30
- Ch. 13 - The Genetic Code and Transcription54
- Ch. 14 - Translation and Proteins47
- Ch. 15 - Gene Mutation, DNA Repair, and Transposition41
- Ch. 16 - Regulation of Gene Expression in Bacteria29
- Ch. 17 - Transcriptional Regulation in Eukaryotes41
- Ch. 18 - Post-transcriptional Regulation in Eukaryotes33
- Ch. 19 - Epigenetics33
- Ch. 20 - Recombinant DNA Technology44
- Ch. 21 - Genomic Analysis36
- Ch. 22 - Applications of Genetic Engineering and Biotechnology36
- Ch. 23 - Developmental Genetics37
- Ch. 24 - Cancer Genetics34
- Ch. 25 - Quantitative Genetics and Multifactorial Traits54
- Ch. 26 - Population and Evolutionary Genetics45
Chapter 12, Problem 6
During what genetic process are lampbrush chromosomes present in vertebrates?
Verified step by step guidance1
Understand what lampbrush chromosomes are: they are large, extended chromosomes with many loops, visible under a microscope during a specific stage of cell division in certain vertebrate cells.
Recall that lampbrush chromosomes are characteristic of the diplotene stage of prophase I during meiosis, where homologous chromosomes are paired and crossing over occurs.
Identify that lampbrush chromosomes are found in oocytes (immature egg cells) of vertebrates, where they facilitate active transcription of genes during this prolonged meiotic stage.
Recognize that the genetic process during which lampbrush chromosomes are present is meiosis, specifically during prophase I when homologous recombination and chromosomal pairing happen.
Summarize that lampbrush chromosomes are a feature of meiotic prophase I in vertebrate oocytes, reflecting a high level of transcriptional activity during this stage.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Lampbrush Chromosomes
Lampbrush chromosomes are large, extended chromosomes found in the oocytes of vertebrates during a specific stage of meiosis. They have distinctive lateral loops that represent active transcription sites, making them visible under a microscope. These chromosomes facilitate high levels of gene expression needed for oocyte development.
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Chromosome Structure
Meiosis and Its Stages
Meiosis is a specialized cell division process that reduces the chromosome number by half to produce gametes. It consists of two divisions: meiosis I and II. Lampbrush chromosomes appear during the prolonged diplotene stage of prophase I, where homologous chromosomes are paired but transcriptionally active.
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Oogenesis in Vertebrates
Oogenesis is the process of egg cell formation in female vertebrates. During oocyte development, meiosis is arrested at the diplotene stage of prophase I, where lampbrush chromosomes are present. This arrest allows extensive transcription to support early embryonic development after fertilization.
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Related Practice
Textbook Question
Describe the structure of giant polytene chromosomes and how they arise.
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Textbook Question
Describe the sequence of research findings that led to the development of the model of chromatin structure.
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Textbook Question
What genetic process is occurring in a puff of a polytene chromosome? How do we know this experimentally?
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Textbook Question
Why might we predict that the organization of eukaryotic genetic material will be more complex than that of viruses or bacteria?
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Textbook Question
Contrast the size of the single chromosome in bacteriophage and T2 with that of E. coli. How does this relate to the relative size and complexity of phages and bacteria?
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