Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes.

Vocabulary:
1. Regulatory Gene: A sequence of DNA encoding a regulatory protein or RNA.

2. Regulatory protein: Any protein that controls the transcription of a gene.

3. Inducer: A molecule that inhibits the repressor of an operon, preventing it from binding with the operator gene.

4. Repressor: A regulatory protein that binds to an operator gene and blocks transcription of the genes of an operon.

5. Cytokine: Any protein, peptide, or glycoprotein produced by a cell in the immune system that acts as a regulator of cells involved in an immune response.

6. Pheromone: A hormone secreted externally by some animals that influences physiology or behavior of other animals belonging to the same species.

7. Morphogen: A diffusible substance that carries information determining cellular position in the embryo, thus determining differentiation of the cells.
8. Intercellular: Of or pertaining to that (e.g. substance, space, region) between the cells
9. Intracellular: Existing, occurring, or functioning within a cell

Enduring Understanding 3.B: Expression of genetic information involves cellular and molecular mechanisms.

Essential Knowledge 3.B.1: Gene regulation results in differential gene expression, leading to cell specialization.

Many things are involved in gene expression, but there are three key points. The first is DNA regulatory sequences. The DNA regulatory sequences are involved in controlling transcription. Next is the regulatory gene, which codes for a protein which in turn interacts with the regulatory sequence in controlling the transcription of a specific gene or group of genes. There are a few key components of the transcription process. First, there is the promoter region. The promoter region, or just promoter, is the site for the RNA polymerase to attach to the DNA sequence being transcribed. This then enables the polymerase to transcribe the gene, putting it into use. The next component is the terminator. The terminator is also a region the RNA polymerase interacts with. When the polymerase reaches this region, it is basically a signal for the polymerase to detach from the DNA sequence and release the newly made RNA sequence. The last component is the enhancer. The enhancer is a DNA segment that has controlling elements for a specific expressed gene. It enhances the performance of that specific gene. In gene expression, there are certain mechanisms that can inhibit or induce an organism’s gene expression. There are inducers, which bind to a repressor and change its shape, stopping it from binding to an operator, thus allowing for the operon to be turned on. The repressor mentioned before has a specific function that was hinted at. The repressors bind to the operators and change its shape, keeping from being able to bind with the gene and turn it on. Then there are the regulatory genes, which can bring on negative and positive effects to gene expression. A negative affect is when the regulatory gene binds to the DNA segment need for transcription, making it impossible for transcription to occur. They can also bring about positive effects. When they bind to the DNA, they can also stimulate it to begin transcription instead of inhibiting it. They may also bind to the repressor, stopping the repressor from changing the shape of the operator. Some genes always need to be turned on. The organism cannot work without that specific function. They help the organism carry out some of DNA’s most important functions. They help it in replication, expression, and help it when it needs fixing. They also help in the maintaining of the organism’s energy levels, especially in its metabolic processes. Gene expression in eukaryotes involves a few different elements than in prokaryotes. IN eukaryotes, there are transcription factors, regulatory genes, and regulatory elements. All of