Silicates Most Commonly Form ________

question 91

Multiple Choice

Silicates most commonly form ________.

• A)at the surface of the earth
• B)from other silicates
• C)from cooling molten rock
• D)under extreme pressure

---

Definitions:

Lac Operon

A regulatory unit in the DNA of bacteria that controls the metabolism of lactose, consisting of genes coding for proteins involved in lactose processing and the regulatory elements controlling them.

Structural Genes

Genes that code for proteins which serve as building blocks for cells and tissues or take part in chemical reactions within the organism.

Regulatory Sequences

DNA sequences that are involved in controlling the expression of genes, determining when and where genes are turned on or off.

Repressible Operon

An operon that is normally active, but can be controlled by a repressor protein, which becomes active when it binds to a corepressor; the active repressor binds to the operator, making the operon transcriptionally inactive. Compare with inducible operon.