Lecture 9: Control of Gene Expression

What is the goal of prokaryotic reproduction?

Reproductive efficiency, not fine-tuning.

What regulates cell roles in eukaryotes during different stages of development?

Cell differentiation.

How does natural selection prioritize bacteria?

It prioritizes bacteria that produce only necessary products for survival and reproduction.

What are operons?

Clusters of functionally related genes under control of a single 'on/off switch'.

What is a repressible operon?

An operon that can be switched on/off by repressor proteins and is usually active.

What is an inducer in the context of an operon?

A substance that switches on an operon that is normally off.

How does glucose affect CAP (catabolic activator protein)?

When glucose levels rise, CAP releases from cAMP.

What is the role of sigma factors in transcription?

They help RNA polymerase recognize the promoter to begin transcription.

What are control elements in gene regulation?

Noncoding portions of DNA that serve as binding sites regulating transcription.

What is histone methylation?

The addition of a methyl group to histones, signaling to densify and inhibit transcription.

What is RNA interference (RNAi)?

Inhibition of gene expression via the actions of noncoding RNA molecules.

What is the function of miRNAs in gene regulation?

They associate with RISC to degrade complementary mRNA and regulate thousands of genes.

What is the purpose of a proteasome in a cell?

To bind to and degrade protein molecules.

What process leads to the specialization of cells in structure and function?

Cell differentiation/specialization.

What are oncogenes?

Cancer-causing genes that are usually normal environmental genes that have mutated.

What do tumor-suppressor genes do?

Prevent uncontrolled cell growth by repairing damaged DNA, controlling cell division, and promoting apoptosis.