Questions and Answers
The condensed chromosomes observed in mitosis include all of the following structures except:
Under the electron microscope, unfolded chromatin resembles 'beads on a string.' What do the 'beads' represent?
In a nucleosome, what is the DNA wrapped around?
Histones
Which of the following statements concerning the eukaryotic chromosome is false?
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If a cell were unable to produce histone proteins, which of the following would be expected to occur?
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Which of the following statements about histones is incorrect?
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Which of the following represents an order of increasingly higher levels of organization?
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Which of the following statements is true?
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Which of the following is least related to the others?
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In a nucleosome, the DNA is wrapped around:
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Muscle cells and nerve cells in one species of animal owe their differences in structure to:
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Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells?
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In which of the following would you expect to find the most methylation of DNA?
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If you were to observe the activity of methylated DNA, you would expect it to:
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Genomic imprinting, DNA methylation, and histone acetylation are all examples of:
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A eukaryotic gene typically has all of the following features except:
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Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA?
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Two potential devices that eukaryotic cells use to regulate transcription are DNA ____ and histone ____.
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In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of:
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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!
