Questions and Answers
Operons are ONLY used by __________ for gene regulation.
prokaryotes
What is the site on the DNA strand where transcription begins?
promoter
What is the on and off switch on the DNA segment that controls whether or not the gene is turned on or off?
operator
What is a protein that can turn off a gene by binding to the operator segment on the DNA strand?
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What do you call the group of genes along with the sections of DNA that regulate them in a prokaryote?
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What is an example of an inducible operon?
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What is an example of a repressible operon?
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What is a regulatory mechanism that involves a repressor protein that turns the operon 'off' called?
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What is the term for when an operon is said to have a protein or enzyme that can turn them 'on' or enhance their function?
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What type of operon is usually off but can be stimulated when a small molecule interacts with the repressor protein?
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What type of operon is usually on but can be inhibited by a small molecule that binds allosterically to a repressor protein?
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What do regulatory genes produce?
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What accumulates and activates CAP when ATP is scarce?
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What is activated by cAMP and binds to the promoter of a lac operon?
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What are the proteins that eukaryotic DNA strands are wound around called?
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What groups bind to histone proteins, causing DNA to be loose and transcribable?
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Without acetyl groups, the eukaryotic DNA would be wound ________ and would not be able to be transcribed.
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What describes eukaryotic DNA that is loosely wound and contains acetyl groups?
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What describes eukaryotic DNA that is tightly wound around histone proteins and does not have acetyl groups?
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When genes are ________ in eukaryotic DNA, they are OFF!
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In eukaryotic gene regulation, what do transcription factors interact with to control gene expression?
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Together, transcription factors and proximal and distal control elements allow for ______ _______ to bind and transcribe the eukaryotic DNA efficiently and effectively.
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The ________ controls what kind of eukaryotic genes are expressed in different cells.
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________ and the ________ control the amount of time that a particular eukaryotic gene is carried out.
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What is it called when different genes come from the same strand because different exons or introns are expressed?
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What are produced by dicer proteins and tag mRNA for degradation or translation blocking?
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What protein chops up mRNA into miRNA?
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What molecule tags a protein that is unnecessary?
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What finds proteins that have been tagged by ubiquitin and chops them up?
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This statement is true.
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Study Notes
Gene Regulation in Prokaryotes
- Prokaryotes utilize operons as a mechanism for gene regulation.
- Operon consists of a group of genes and DNA segments that regulate them.
Key Components of Operons
- Promoter: The starting point for transcription where RNA polymerase binds to DNA.
- Operator: Functions as an on/off switch to control the gene's activity.
- Repressor: A protein that inhibits gene expression by binding to the operator.
Types of Operons
- Inducible Operon: Typically in an OFF state, it can be activated when a small molecule interacts with the repressor, allowing transcription (e.g., lac operon).
- Repressible Operon: Generally in an ON state, it can be turned OFF when a small molecule binds to a repressor, preventing transcription (e.g., trp operon).
Regulatory Mechanisms
- Negative Control: A repressor protein turns the operon OFF.
- Positive Control: Enhancements allow transcription to occur more readily, via a protein that facilitates RNA polymerase's binding to the promoter.
Regulatory Genes
- Produce repressor proteins continuously at a low rate, located away from the operon with its own promoter.
Eukaryotic Gene Regulation
- Histones: Proteins around which eukaryotic DNA is wound; their modification influences transcription.
- Acetyl Groups: Attach to histones, loosening DNA winding for transcription accessibility.
- Euchromatin: Loosely wound DNA with acetylated histones, transcriptionally active.
- Heterochromatin: Tightly wound DNA lacking acetyl groups, transcriptionally inactive.
DNA Methylation and Gene Expression
- Methylated genes in eukaryotic DNA are typically OFF.
Interaction of Transcription Factors
- Transcription factors engage with proximal and distal control elements to regulate gene expression, enabling efficient binding of RNA polymerase.
Environmental Influence
- The environment impacts the expression of eukaryotic genes, facilitating cell differentiation.
Transcriptional Modifications
- 5' Capping and 3' Poly-A Tail: Modification processes that affect the stability of eukaryotic mRNA.
- Alternative Splicing: Mechanism that results in multiple proteins from a single gene by varying exon inclusion/exclusion.
RNA Interference
- miRNA (micro RNA): Small RNA molecules that tag mRNA for degradation or inhibit translation.
- Dicer Protein: Enzyme that processes precursor RNA into miRNA.
Protein Tagging and Degradation
- Ubiquitin: Tags unnecessary proteins for degradation.
- Proteasome: Cellular machinery that degrades tagged proteins.
Summary of Gene Regulation
- Gene regulation is crucial for cellular function and differentiation, with various mechanisms operating at both prokaryotic and eukaryotic levels.
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Description
Explore essential concepts in gene regulation with this quiz based on AP Biology Unit 6. Review important terms such as prokaryotes, promoters, operators, and repressors, which are fundamental for understanding how genes are controlled. Perfect for students preparing for exams or seeking to reinforce their knowledge.
