All Flashcards
Differentiate between enhancers and silencers.
Enhancers: Increase transcription. Silencers: Decrease transcription.
What are the differences between DNA methylation and histone acetylation?
DNA Methylation: Generally represses gene expression. Histone Acetylation: Generally promotes gene expression.
Compare and contrast the lac and trp operons.
lac operon: inducible, activated by lactose. trp operon: repressible, repressed by tryptophan.
Differentiate between genotype and phenotype.
Genotype: Genetic makeup. Phenotype: Observable traits resulting from gene expression.
Compare gene regulation in prokaryotes and eukaryotes.
Prokaryotes: Primarily operons. Eukaryotes: Transcription factors and epigenetic modifications.
Compare the roles of activators and repressors in transcription.
Activators: Increase transcription by aiding RNA polymerase binding. Repressors: Decrease transcription by blocking RNA polymerase binding.
How do regulatory sequences control gene expression?
Interact with regulatory proteins (transcription factors) to activate or repress transcription by recruiting or inhibiting RNA polymerase binding.
Briefly describe the process of epigenetic modification.
Involves DNA methylation (gene repression) and histone modification (altering chromatin structure) influencing DNA accessibility.
How does the lac operon function in the presence of lactose?
Lactose binds to the repressor protein, inactivating it and allowing transcription of the lac operon genes.
How does the lac operon function in the absence of lactose?
Repressor protein binds to the operator, preventing transcription of the lac operon genes.
Outline the steps of gene expression in the presence of an enhancer.
Enhancer binds transcription factors, increasing transcription rate by aiding RNA polymerase binding to the promoter.
Outline the steps of gene expression in the presence of a silencer.
Silencer binds transcription factors, decreasing transcription rate by inhibiting RNA polymerase binding to the promoter.
Define regulatory sequences.
DNA sequences that control gene expression by increasing or decreasing transcription; located near promoter regions.
What is the definition of enhancers?
Regulatory sequences that increase transcription.
What is the definition of silencers?
Regulatory sequences that decrease transcription.
Define epigenetic changes.
Heritable changes in gene function without altering the DNA sequence itself.
What is DNA methylation?
The addition of a methyl group to a DNA base, typically cytosine, leading to gene repression.
What is histone modification?
Changes to the structure of histone proteins, such as acetylation or methylation, that alter chromatin structure and affect DNA accessibility to transcription machinery.
Define phenotype.
The observable characteristics of a cell or organism, determined by gene expression.
What is cell differentiation?
The process by which different cell types acquire distinct functions and characteristics through differential gene expression.
Define operons.
Groups of genes transcribed together into a single mRNA molecule, controlled by a single promoter (primarily in prokaryotes).
Define coordinated regulation.
Groups of genes controlled together for efficient expression of genes involved in the same cellular process.