Genetics Key Terms #8

Front 1

adenyl cyclase

Back 1

An enzyme which catalyzes the conversion of ATP to cAMP.

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allosteric

Back 2

Conformational change in the active site of a protein brought about by interaction with an effector molecule.

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antiterminator hairpin (E. coli trp operon)

Back 3

An alternate structure to a terminator structure. Transcription in this case proceeds past the antiterminator region, and entire mRNA is subsequently produced.

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attenuation (E. coli trp operon)

Back 4

Form of repression in which the transcription of the operon is greatly reduced rather than prevented entirely.

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attenuator (E. coli trp operon)

Back 5

A nucleotide sequence between the promoter and the structural gene of some bacterial operons that regulates the transit of RNA polymerase, reducing transcription of the related structural gene.

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bacterial promoter

Back 6

An upstream region of a gene serving a regulatory function and to which RNA polymerase binds prior to the initiation of transcription.

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B-galactosidase

Back 7

A bacterial enzyme, encoded by the lacZ gene, that converts lactose into galactose and glucose.

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cAMP

Back 8

Molecule is which CAP binding is dependent. In order to bind the promoter, CAP must be bound to cAMP.

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Catabolite Activating Protein (CAP)

Back 9

A protein that binds cAMP and regulates the activation of inducible operons.

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Catabolite Repression

Back 10

The selective inactivation of an operon by a metabolic product of the enzymes encoded by the operon.

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cis-acting site

Back 11

A DNA sequence that regulates the expression of a gene located on the same chromosome. This contrasts with trans-acting element where regulation is under the control of a sequence on the homologous chromosome.

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constitutive mutation

Back 12

In cells bearing constitutive mutations, enzymes are produced regardless of the presence of the presence or absence of lactose.

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Cooperative binding

Back 13

When cAMP-CAP or RNA polymerase are together in the presence of the lac promoter DNA, a tightly bound complex is formed.

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Coordinate Regulation of genes

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idk

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Gratutious Inducer

Back 15

Chemical analogs of lactose such as the IPTG. Behave like natural inducers, but they do not serve as substrates for the enzymes that are subsequently synthesized.

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Inducible Enzyme

Back 16

An enzyme system under the control of an inducer, a regulatory molecule that acts to block a repressor and allow transcription

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IPTG

Back 17

Lactose metabolite that triggers transcription of the lac operon.

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lac operon

Back 18

Three structural genes and the adjacent regulatory site constitute the lac operon. Together, the entire cluster functions in an integrated fashion to provide a rapid response to the presence or absence of lactose

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laci+, laci-,laciS

Back 19

Constitutive mutations, enzymes which are produced regardless of the presence or absence of lactose. Laci is called a repressor gene.

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lacOc,lacO+

Back 20

Mutations located in the operator region of the operon. Inducibility is eliminated, and gene regulation has been lost.

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lacP+, lacP-

Back 21

idk yet

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lactose

Back 22

a dissacharide sugar that is found most notably in milk and is formed from galactose and glucose.

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lactose permease

Back 23

lacY. An enzyme that facilitates the entry of lactose into the bacterial cell.

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lacY+, lacY-

Back 24

lacY- is a mutant cell that cannot use lactose as an energy source.

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lacZ+, lacZ-

Back 25

Mutant cells of B-galactosidase that are unable to use lactose as an energy source.

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leader sequence

Back 26

That portion of an mRNA molecule from the 5'end to the initiating codon, often containing regulatory or ribosome binding sites.

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merozygote

Back 27

a partially diploid bacterial cell containing, in addition to its own chromsome, a chromosome fragment introduced into the cell by transformation, transduction or conjugation

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negative control

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Genetic expression occurs unless it is shut off by some form of regulator molecule

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positive control

Back 29

Transcription occurs onnly if a regulator molecule directly stimulates RNA production.

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operator

Back 30

in bacterial DNA, a region that interacts with a specific repressor protein to regulate the expression of an adjacent gene or gene set

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repressible enzyme (gene)

Back 31

An enzyme or group of enzymes whose synthesis is regulated by the intracellular concentration of certain metabolites.

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repressor

Back 32

A protein that binds to a regulatory sequence adjacent to a gene and blocks transcription of the gene