Topic 12 Control of Gene Expression Vocab #1-32

Vocab

virus

Particle made up of nucleic acid, protein, and in some cases lipids that can replicate only by infecting living cells.

capsid

The outer covering of protein surrounding the nucleic acid of a virus

capsomere

A protein that makes up the structure of a viral capsid.

virus genome

DNA or RNA that make up the genetic molecule of a virus.

DNA virus

A virus whose genome consists of DNA.

RNA virus

A virus whose genome consists of RNA.

viral envelope

A membrane, derived from membranes of the host cell, that cloaks the capsid, which in turn encloses a viral genome.

glycoprotein

A protein with one or more carbohydrates covalently attached to it.

bacteriophages (phages)

Viruses that infect bacteria.

parasite

An organism that lives on or in a host and causes harm to the host.

host range

The limited number of cells that each type of virus can infect and parasitize.

lytic cycle

a viral reproductive cycle in which copies of a virus are made within a host cell, which then bursts open, releasing new viruses.

lysogenic cycle

A viral reproductive cycle in which the viral DNA is added to the host cell's DNA and is copied along with the host cell's DNA.

virulent phage

A phage that reproduces only by a lytic cycle.

restriction enzymes

Enzyme that cuts DNA at a specific sequence of nucleotides.

provirus

Viral DNA that inserts into a host genome.

prophage

The viral DNA that is embedded in the host cell's DNA of a bacterium.

temperate phages

Phages that are capable of using either the lytic or lysogenic cycle.

reverse transcriptase

A polymerase that catalyzes the formation of DNA using RNA as a template.

retroviruses

An RNA virus that reproduces by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome.

HIV

The retrovirus that causes AIDS.

AIDS

A syndrome caused by the human immunodeficiency virus (HIV) that renders immune cells ineffective, permitting opportunistic infections, transmitted sexually or through contaminated blood.

ebola

A contagious viral disease transmitted by blood and body fluids and causes body organs and vessels to leak blood, usually resulting in death.

plasmid

A circular DNA molecule that is usually found in bacteria and that can replicate independent of the main chromosome.

transposon

A segment of DNA that can become integrated at many different sites along a chromosome.

gene regulation

Ability of an organism to control which genes are transcribed in response to the needs of the organism.

operon

A unit of gene regulation and transcription in bacterial DNA that consists of a promoter, an operator, and one or more structural genes.

operator

Region of chromosome in an operon to which the repressor binds when the operon is "turned off".

repressor

A protein that binds to an operator and physically blocks RNA polymerase from binding to a promoter site.

regulatory gene

A gene that codes for a protein, such as a repressor, that controls the transcription of another gene or group of genes.

corepressor

A small molecule that binds to a bacterial repressor protein and changes its shape, allowing it to switch an operon off.

positive gene regulation

When a regulatory protein interacts with the operator to turn on gene expression.