Operon Hypothesis, Genetic Aberration

Flashcards covering vocabulary terms from the lecture notes.

Operon

Genes that code for functionally related enzymes and are turned on or off as a unit.

Operator

A switch-like gene that controls the operon.

Operon

The operator and its adjacent structural genes.

Regulator Gene

A control gene that produces a repressor protein.

Repressor

A protein produced by the regulator gene that unites with the operator to keep it in the off position.

Inducer

A substance that reacts with the repressor, preventing it from tying up the operator and turning the operon on.

Lac Operon

Produces enzymes necessary for the degradation of lactose.

β-galactosidase

An enzyme that cleaves lactose into glucose and galactose.

Permease

An enzyme that facilitates the passage of lactose into the bacterial cell.

Transacetylase

Promotes the transfer of an acetyl group from acetyl-CoA to galactose.

Corepressor

An intrusive environmental molecule activates the repressor and turns the operon off.

End-product Inhibition

Turning off a process by the end product of that process.

Cyclic AMP Binding Protein (CAP)

A protein capable of combining with cyclic AMP that increases the promoter’s capacity to bind with RNA polymerase.

Temperate Virus

A virus that integrates with the host chromosome.

Lysogeny

The phenomenon in which a “low lying” virus produces periodic bursts of infection.

Prophages

Integral viral particles.

Cistron

Functional unit for polypeptide or protein coding.

Muton

Smallest number of bases that when mutated produce a phenotypic change.

Recon

Part of the cistron involved in an exchange of gene information (recombination) between two chromosomes.

Exons

Coding bands in split genes.

Introns

Noncoding regions that split the gene.

Highly Repetitive DNA

Base sequences are found many thousands of times within the genome.

Moderately Repetitive DNA

Sequences are found hundreds of times throughout the chromosome.

Single-copy DNA

The source of the protein-coding (structural) genes within the chromosome.

Pseudogenes

Nonfunctional sequences almost identical with true structural genes.

Euchromatin

Genes that are actively involved in transcription and translation found along less deeply staining portions of the chromosome.

Heterochromatin

Deeply stained regions generally contain genes that were never or are no longer active.

Chromosome Puffs

Clusters of DNA loops with large amounts of enmeshed RNA that burgeon out from regions of activated exons in the chromosome.

Amplification

The process of copying entire sets of genes many times to provide needed RNA or protein species.

Undermethylation

A fundamental molecular mechanism for gene activation.

Eukaryotic Initiation Factors (eIFs)

Factors required to begin translation in eukaryotes.

Cancers

Cell populations that show unrestrained growth.

Metastasis

The widespread colonization of distant regions of the body by cancer cells.

Contact Inhibition

The tendency of cells to stop growing when they come into contact with other cells.

Carcinogens

Agents that cause cancer and produce mutations.

Oncogenes

Genes whose presence and activity appear to be involved in the transformation of normal cells to cancerous cells.

Protooncogenes

Ordinary genes within the host, which when altered becomes an oncogene.

Insertional Tumorigenesis

The incorporation of a retrovirus by a normal cell.