1 .		2.1 Concept Check All microbial cells have certain basic structures in common such as a cytoplasmic membrane, ribosomes and (usually) a cell wall. Two structural categories of cells are recognized: the prokaryote and the eukaryote. Viruses are not cells but depend on cells for their replicative functions. By looking inside a cell how could you tell if it were prokaryotic or eukaryotic? What important function do ribosomes play in cells? How long is a typical rod-shaped bacterial cell? How much larger are you than this single cell?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
2 .		2.2 Concept Check Genes govern the properties of cells, and a cell's complement of genes is referred to as its genome. DNA is arranged in cells to form chromosomes. In prokaryotes there is usually a single circular chromosome, while in eukaryotes, several linear chromosomes exist. Differentiate between the nucleus and the nucleoid. How do plasmids differ from chromosomes? Why does it make sense that a human cell would have more genes than a bacterial cell?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
3 .		2.3 Concept Check Ribosomal RNA sequencing has revolutionized microbiology and has yielded an evolutionary framework for the prokaryotes. The three domains of life are the Bacteria, the Archae, and the Eukarya have evolutionary roots in the Bacteria and has yielded new tools for microbial ecology and diagnostics. What evidence supports the idea that Bacteria and Archae are different? In what ways are they similar? What molecular evidence supports the theory of endosymbiosis?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
4 .		2.4 Concept Check Sources of energy and carbon are needed by all cells. The terms chemoorganotroph, chemolithotroph, and phototroph refer to cells that use organic chemicals, inorganic chemicals, or light, respectively, as their source of energy. Autotrophic organisms use CO2 as their carbon source. Many prokaryotes thrive under environmental conditions that humans would call extreme. How might you distinguish a phototrophic organism from a chemotrophic one by simply looking at it under a microscope? What are extremophiles?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
5 .		2.5 Concept Check Several lineages are present in the domains Bacteria and Archae, and an enormous diversity of cell morphologies and physiologies are represented there. Retrieval and analysis of ribosomal RNA genes from cells in natural samples have shown that many phylogenetically distinct but as yet uncultured prokaryotes exist in nature. What important bacterial species that resides in your gut is a member of the Proteobacteria? Why can it be said that the cyanobacteria prepared the Earth for the evolution of higher life forms? What is unusual about species of the genus Halobacterium? How do we know a particular lineage of prokaryotes exists in nature, without growing a culture of it in the laboratory?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
6 .		2.6 Concept Check Microbial eukaryotes are a diverse group that includes algae, protozoa, fungi, and slime molds. Some algae and fungi have developed mutualistic associations called lichens. List at least two ways algae differ from cyanobacteria. List at least two ways algae differ from protozoa. How do the components of a lichen benefit each other?   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.