BIOL-1240 Gene Expression-Operons Ch 16

Genes that code for the proteins that are constantly needed for survival of an organism are

• promoters

• constitutive genes

• operons

• repressor genes

• always "on"

A repressor usually controls an inducible gene by

• keeping it "turned off"

• suppressing mRNA production

• reducing product resulting from an active inducer

• inducing an antagonist

• blocking DNA replication at specific sites

The basic way(s) that cells control their metabolic activities is/are by

• regulating enzyme activity

• mutations

• developing different genes for different purposes

• controlling the number of enzyme molecules

• transduction

The genes and genetic information in different cells of multicellular organisms are

• all slightly different

• distinctly different

• identical in the same tissues, different in the different tissues

• almost all identical

Replication in specific genes in cells that need more of them is an example of

• magnification

• amplification

• induction

• a positive control system

• a regulon

____ genes are genes that encode essential proteins that are in constant use.

The ____ is a sequence of bases that switches mRNA synthesis "on" or "off."

One would expect a gene involved in the manufacture of ATP to be

• "off" usually

• always "on"

• facultative

• a constitutive gene

• sometimes "off", sometimes "on"

The tryptophan operon in E. coli is

• usually on

• on in the absence of corepressor

• repressed only when tryptophan binds to repressor

• an inducible system

• a repressible system

The lactose operon in E. coli

• contains three structural genes

• is turned on by a repressor

• is a repressor

• is an inducible system