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.
What happens when DNA is methylated?
Gene expression is typically repressed.
What is the effect of histone acetylation?
Increased gene expression due to relaxed chromatin structure.
What happens when lactose is present in the lac operon?
The repressor protein is inactivated, allowing transcription of the lac operon genes.
What is the effect of low glucose levels on the lac operon?
CAP protein binds to the promoter, enhancing RNA polymerase binding and increasing transcription.
What happens when tryptophan levels are high in the trp operon?
The trp operon is turned off, preventing further tryptophan synthesis.
What is the effect of mutations in regulatory sequences?
Can lead to dysregulation of gene expression and diseases, including cancer.