Ch. 19 Vocab

Viruses

HIV (human immunodeficiency virus)

HIV (human immunodeficiency virus)

the infectious agent that causes AIDS. A retrovirus.

prophage

a phage genome that has been inserted into a specific site on a bacterial chromosome

lysogenic cycle

a type of phage replicative cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage, is replicated along with the chromosome, and does not kill the host

lytic cycle

a type of phage replicative cycle resulting in the release of new phages by lysis (and death) of the host cell

foot

the portion of a byrophyte sporophyte that gathers sugars, amino acids, water, and minerals from the parent gametophyte via transfer cells.

one of the three main parts of a mollusc; a muscular structure usually used for movement

epidemic

a widespread outbreak of a disease in a community at a particular time

provirus

a viral genome that is permanently inserted into a host genome

capsid

the protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape

capsule

in many prokaryotes, a dense and well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells.

the sporangium of a byrophyte (moss, liverwort, or hornwort)

restriction enzyme

an endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites).

bacteriophage

a virus that infects bacteria; also called a phage

seed

an adaptation of some terrestrial plants consisting of an embryo packaged along with a store of food within a protective coat

virulent phage

a phage that replicates only by a lytic cycle

phage

a virus that infects bacteria; also called a bacteriophage

reverse transcriptase

an enzyme encoded by certain viruses (retroviruses) that uses RNA as a template for DNA synthesis

host range

the limited number of species whose cells can be infected by a particular virus

prion

an infectious agent that is misfolded version of a normal cellular protein. They appear to increase in number by converting correctly folded versions of the protein to more prions

retrovirus

an RNA virus that replicates by transcribing its RNA into DNA and then inserting the DNA into a cellular chromosome; an important class of cancer-causing viruses

temperate phage

a phage that is capable of replicating by both a lytic or lysogenic cycle

viral envelope

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

AIDS (acquired immunodeficiency syndrome)

the symptoms and signs present during the late stages of HIV infection, defined by a specified reduction in the number of T cells and the appearance of characteristic secondary infections

pandemic

a global epidemic

vaccine

a harmless variant or derivative of a pathogen that stimulates a host’s immune system to mount defenses against the pathogen

virus

an infectious particle consisting of genes packaged in a protein coat

endemic

A disease that exists permanently in a particular region

sporadic

Diseases that are seen only occasionally, and usually without geographic concentration

Vertical transmission

one way plant viruses spread disease; by inheriting the virus from a parent

Horizontal transmission

one way plant viruses spread disease; entering through damaged cell walls