Genetics Chapter 14 Vocabulary

Constitutive genes

unregulated genes that are expressed all the time

Homodimers

two of the same protein

Major/Minor grooves

non-covalent bonds

Alternative Sigma factors

recognize different sets of promoters to control expression of regulated genes

Sigma 70 transcription

transcribes all constitutive genes

Regulatory proteins

repressors and activators

Repressors

A protein that suppresses the transcription of a gene

Activators

A protein that boosts the transcription of a gene

Operator site

location where the repressor binds, downstream of the promoter site

Activator site

location where the activator protein binds, upstream of the promoter

Promoter

region of DNA where the RNA polymerase binds to start transcription, recognized by sigma factors

Negative control of transcription

a regulatory mechanism that stops or slows transcription, through a repressor protein

Positive control of transcription

a regulatory mechanism that helps boost transcription through an activator protein

Effector molecules

inducers, corepressors, inhibitors

Inducers

molecules that bind to repressors or activators that help induce transcription

Corepressors

molecules that bind to repressor proteins and cause them to bind to the operator site

Inhibitors

molecules that bind to the activator proteins to change conformation so they cannot bind to the activator site

Conformation

the shape of the protein that allows or does not allow it to function correctly

Inducible genes

involved in catabolic processes

Repressible genes

involved in anabolic processes

Regulated genes

genes that are only expresses during specific processes and conditions of the cell