Prokaryotic Gene Regulation
This cluster of functionally related genes is transcribed as a single polycistronic mRNA.
What is an operon?
The “ground state” of gene expression in eukaryotes is typically this.
What is off?
This model describes the membrane as a two-dimensional fluid with embedded proteins.
What is the fluid mosaic model?
This type of movement describes sideways diffusion of lipids within the membrane.
What is lateral diffusion?
This 5′ UTR element can bind small metabolites and regulate transcription elongation.
What is a riboswitch?
This operon is an inducible operon involved in lactose metabolism.
What is the lac operon?
DNA methylation typically results in this effect on transcription.
What is gene silencing / repression?
These amphipathic molecules form the structural foundation of membranes.
What are phospholipids?
This enzymatic activity moves phospholipids between leaflets of the bilayer.
What are flippases?
These small RNAs are processed by Drosha and Dicer.
What are microRNAs (miRNAs)?
This molecule binds to the trp repressor and activates it, allowing repression.
What is tryptophan?
These DNA elements can be located kilobases away and increase transcription.
What are enhancers?
This membrane component acts as a fluidity buffer in animal cells.
What is cholesterol?
Carbohydrates are found exclusively on this membrane face.
What is the exoplasmic (extracellular) face?
Gradual shortening of this structure decreases mRNA stability.
What is the poly-A tail?
This protein works with cAMP to enhance transcription of the lac operon.
What is CAP (catabolite activator protein) / CRP?
This type of RNA (>200 nucleotides) can scaffold chromatin modifiers and regulate gene expression.
What is lncRNA (long non-coding RNA)?
These membrane proteins span the bilayer and often contain hydrophobic α-helices.
What are transmembrane proteins?
During apoptosis, this phospholipid flips to the outer leaflet as a death signal.
What is phosphatidylserine (PS)?
This enzyme cleaves double-stranded RNA into siRNA fragments.
What is Dicer?
This ribosome-dependent regulatory mechanism controls transcription elongation in the trp operon.
What is attenuation?
This complex, formed by siRNA and proteins, targets complementary mRNA for degradation.
What is siRISC?
This membrane domain is enriched in sphingolipids and cholesterol and is involved in signaling.
What are lipid rafts?
This term describes the unequal distribution of lipids and proteins between membrane leaflets.
What is membrane asymmetry?
This epigenetic mechanism can silence either the maternal or paternal allele.
What is genomic imprinting?