Gene Expression and Regulation

The metabolic product interferes directly with ribosome function during translation of these enzymes.

The end product acts as a corepressor that activates a repressor protein which binds to the operator site and blocks RNA polymerase.

The surplus metabolite enhances allosteric activation of transcription factors for unrelated genes' promoters.

The end product increases degradation rate of mRNA coding for these enzymes through ribonuclease activity.

tRNA

DNA polymerase

rRNA

mRNA

A protein that turns on RNA polymerase

Activators are not present in positive gene regulation

A protein that induces repressors to make them inactive so transcription occurs

A protein that binds upstream of the DNA stimulates the transcription of a gene

They lead to heritable changes in gene function without changes to DNA sequence.

They directly form the structure of chromosomes.

They control the activation or repression of genes.

They encode for specific proteins.

Greater utilization of stored fats and proteins for cellular energy needs.

Increased reliance on anaerobic pathways like lactic acid fermentation.

Reduced energy capture for synthesizing carbohydrates via photosynthesis.

Elevated rates of photorespiration resulting in more efficient growth.

Only males are affected by the trait.

Affected individuals are usually homozygous dominant.

The trait appears in every generation.

Most affected individuals have unaffected parents.

The Repressor Protein Stays Bound To The Operator

RNA Polymerase Cannot Bind To The Promoter

Allolactose Does Not Act As An Inducer

The Lac Operon Will Not Be Fully Activated

They increase efficiency during translation by acting as adaptors between codons on mRNAs and amino acids carried by tRNAs.

They facilitate faster mRNA processing by aiding in the addition of poly(A) tails and caps needed for stability and exportation from nucleus.

They can lead to mRNA degradation or block translation by binding mRNA and recruiting other proteins that interfere with these processes.

They enhance ribosomal attachment to mRNAs through alterations in secondary structures making them more accessible for translation initiation factors.

They bind complementary sequences on mRNA molecules leading to degradation or repression translation

...

They catalyze addition methyl groups onto DNA suppressing transcriptional activity

They facilitate acetylation histones which results tighter packing preventing access RNA polymerase

Corepressors enhance production from transcription

Corepressors bind themselves to the promotor and halt transcription

Corepressors cooperate with repressors to switch an operon off

Corepressors terminate the transcription process