barm - a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey. yeast. yeast cake - small cake of compressed moist yeast. brewer's yeast - yeast used in fermenting beer. leaven, leavening - a substance used to produce fermentation in dough or a liquid. mother - a stringy slimy substance consisting of yeast cells and bacteria; forms during fermentation and is added to cider or wine to produce vinegar.
1 Viruses, on the other hand, do not have any cells. 2  Viruses are made up of a protein structure called a capsid. 3  Though this capsid contains the virus's genetic material, it lacks the features of a true cell, such as cell walls, transport proteins, cytoplasm, organelles, and so on. Viruses, on the other hand, do not have any cells. 2  Viruses are made up of a protein structure called a capsid. 3  Though this capsid contains the virus's genetic material, it lacks the features of a true cell, such as cell walls, transport proteins, cytoplasm, organelles, and so on.
Viruses can contain either DNA or RNA or even both, but its uncommon for them to have both. Most, however do contain RNA. Usually they just contain one or the other (usually RNA), not both. Viruses are usually very simple--genetic material and a way to implant it in cells. Viruses do not carry DNA, but actually RNA which a host cell converts to DNA using RNA Transcriptase.