Biol211 Chapter 18

Front

What is an inducible operon?

Back

An inducible operon is a type of operon that is usually off but can be turned on (induced) in the presence of a specific substrate or signal, allowing for the transcription of genes involved in metabolizing that substrate.

Front

What happens if the repressor of an inducible operon cannot bind the operator?

Back

If the repressor cannot bind the operator, the operon will undergo continuous transcription of its genes, regardless of the presence of the substrate.

Front

What is the role of bicoid mRNA in Drosophila development?

Back

Bicoid mRNA is crucial for anterior-posterior axis formation in Drosophila; its absence leads to the lack of anterior structures and mirror-image duplication of posterior parts.

Front

What is a corepressor in the context of operons?

Back

A corepressor is a molecule that binds to a repressor protein, enabling it to bind to the operator and inhibit transcription of the operon.

Front

What are homeotic genes?

Back

Homeotic genes are regulatory genes that determine the identity of body segments in an organism; mutations can lead to the development of inappropriate structures, such as legs instead of antennae.

Front

How do histone acetylases affect transcription?

Back

Histone acetylases activate transcription by adding acetyl groups to histone proteins, which opens up chromatin structure and allows for easier access to DNA.

Front

What is the function of a repressor in gene regulation?

Back

A repressor is a protein that binds to the operator region of an operon, preventing transcription of the associated genes.

Front

What is the trp operon and how is it regulated?

Back

The trp operon is a repressible operon that encodes enzymes for tryptophan synthesis; it is regulated by the presence of tryptophan, which acts as a corepressor.

Front

What is the significance of transcription factors?

Back

Transcription factors are proteins that help regulate the transcription of specific genes by binding to nearby DNA.

Front

What is chromatin and its role in gene expression?

Back

Chromatin is a complex of DNA and proteins that forms chromosomes; its structure can influence gene expression by either allowing or restricting access to the DNA.