Biology Final Flashcards: Mitosis and Chromatin
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Questions and Answers

The condensed chromosomes observed in mitosis include all of the following structures except:

  • Centromeres
  • Chromatids
  • Chromatin
  • Ribosomes (correct)
  • Under the electron microscope, unfolded chromatin resembles 'beads on a string.' What do the 'beads' represent?

  • Histones
  • Nucleosomes (correct)
  • DNA
  • Chromatin
  • In a nucleosome, what is the DNA wrapped around?

    Histones

    Which of the following statements concerning the eukaryotic chromosome is false?

    <p>The number of genes on each chromosome is different in different cell types.</p> Signup and view all the answers

    If a cell were unable to produce histone proteins, which of the following would be expected to occur?

    <p>The cell's DNA couldn't be packed into its nucleus.</p> Signup and view all the answers

    Which of the following statements about histones is incorrect?

    <p>Histones are found in mammals, but not in other animals or in plants.</p> Signup and view all the answers

    Which of the following represents an order of increasingly higher levels of organization?

    <p>Nucleosome, 30-nm chromatin fiber, looped domain</p> Signup and view all the answers

    Which of the following statements is true?

    <p>Heterochromatin is highly condensed, whereas euchromatin is less compact.</p> Signup and view all the answers

    Which of the following is least related to the others?

    <p>Pseudo genes</p> Signup and view all the answers

    In a nucleosome, the DNA is wrapped around:

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

    Muscle cells and nerve cells in one species of animal owe their differences in structure to:

    <p>Differential gene expression</p> Signup and view all the answers

    Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells?

    <p>Both A and B</p> Signup and view all the answers

    In which of the following would you expect to find the most methylation of DNA?

    <p>Inactivated mammalian X chromosomes</p> Signup and view all the answers

    If you were to observe the activity of methylated DNA, you would expect it to:

    <p>Have turned off or slowed down the process of transcription</p> Signup and view all the answers

    Genomic imprinting, DNA methylation, and histone acetylation are all examples of:

    <p>Epigenetic inheritance</p> Signup and view all the answers

    A eukaryotic gene typically has all of the following features except:

    <p>An operator</p> Signup and view all the answers

    Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA?

    <p>2%</p> Signup and view all the answers

    Two potential devices that eukaryotic cells use to regulate transcription are DNA ____ and histone ____.

    <p>methylation; acetylation</p> Signup and view all the answers

    In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of:

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

    Study Notes

    Chromosome Structures and Components

    • Condensed chromosomes during mitosis do not include ribosomes.
    • Under electron microscopy, unfolded chromatin appears like "beads on a string," where "beads" represent nucleosomes.
    • Nucleosomes consist of DNA wrapped around histone proteins.

    Eukaryotic Chromosomes

    • A false statement regarding eukaryotic chromosomes is that gene number differs among various cell types.
    • An inability to produce histone proteins results in DNA not being compacted into the nucleus.
    • Incorrect assertion: Histones are exclusive to mammals and absent in other animals and plants.

    Levels of Organization

    • The increasing order of chromatin organization is nucleosome, 30-nm chromatin fiber, looped domain.
    • Heterochromatin is described as highly condensed, whereas euchromatin is less compact.

    Gene Expression and Regulation

    • Non-coding regions such as pseudo genes are least related to the other terms.
    • Structural differences in muscle and nerve cells of the same species arise from differential gene expression.
    • Mechanisms for coordinated gene expression include clustering of related genes and shared control elements for transcription initiation.

    DNA Methylation and Gene Regulation

    • Highest DNA methylation is found in inactivated mammalian X chromosomes.
    • Methylated DNA typically results in decreased transcriptional activity.
    • Genomic imprinting, DNA methylation, and histone acetylation are methods of epigenetic inheritance.

    Gene Structure

    • Eukaryotic genes generally lack operators as a structural feature.
    • Approximate 2% of the human genome encodes for proteins or functional RNA.

    Transcription Regulation

    • Eukaryotic cells utilize DNA methylation and histone acetylation as regulatory mechanisms for transcription.
    • In both eukaryotes and prokaryotes, gene expression regulation is primarily executed at the transcriptional level.

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    Description

    Prepare for your biology final with these flashcards focusing on mitosis and chromatin structure. Each card presents key concepts, such as the role of nucleosomes and histones. Test your knowledge and get ready for exam success!

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