Ch.13 Gene Regulation

Polycistronic mRNA

An mRNA that encodes more than one protein.

Constitutive Genes

An unregulated gene that has constant levels of expression in all conditions over time.

Activators

Bind to the DNA and increase the rate of transcription.

Structural Genes

Code for proteins.

Regulatory Gene

Codes for transcription factors that regulate transcription of the operon.

Lac Operon

Contains the genes for proteins that allow it to metabolize lactose.

Regulatory Transcription Factors

Proteins that bind to DNA in the vicinity of a promoter and affect the rate of transcription of one or more nearby genes.

Promoter Region

For mRNA polymerse recognition.

Proteomes

The collection of proteins they make - are quite different; this is due to gene regulation.

Cis acting element

a DNA segment that must be adjacent to the gene that it regulates. ex. The lac operon

Trans- effect

a form of gene regulation that can occur even though two DNA segments are not physically adjacent .

Gene Expression

Is the process by which the information within the gene is made into a functional product, such as a protein or RNA molecule.

Genome

Meaning they carry the same set of genes .

Gene Regulation

Refers to the ability of cells to control the expression of their genes.

Cell Differentation

The process by which cells become specialized into particular types.

Operator

The regulatory switch (on or off) that the transcription factor will bind to.

Represors

Transcription factors that bind to DNA , and inhibit transcription .

inducer

a small effector molecule that increases the rate of transcription.

Operons

are cluster of genes that code for proteins that are used for common function . They consist of a regulatory gene, a promoter gene, an operator gene, and the structural gene.

Hemoglobin protein

is composed of four globin polypeptides, two incoded by one globin gene and two encoded by another globin gene.