Microbiology

1. How can prokaryotic cells be smaller than eukaryotic cells and still carry on all the functions of life?

* Prokaryotes are essentially a more primitive kind of cell - eukaryotes are larger because they have adapted from prokaryotes through evolution, and their complexity allows support for the larger cell. The smaller size of a prokaryote gives it a larger surface area to volume ratio, meaning that in the absence of various carrier systems found in eukaryotes, such as golgi complexes and vesicles, metabolic compounds and various nutrients are easily diffused into the various parts of the cell to where it needs to get to. Because they are generally less complicated than eukaryotes (the amount of DNA and number of genes is significantly less), they are able to perform the basic functions of life in a smaller cell.

2. The smallest eukaryotic cell is the motile alga Micromonas. What is the minimum number of organelles this alga must have?

* Nucleus, Mitochondria, Chloroplast, Flagellum

3. Two types of prokaryotic cells have been distinguished: bacteria and archaea. How do these cells differ from each other? How are they similar?

* Similar: Prokaryotic and single-celled Different: Bacteria cell walls have peptidoglycan, Archaea is composed of branched carbon chains, Bacteria is composed of straight carbon chains.

4. ln 1985. a O.5-mm cell was discovered in surgeonfish and named Epulopiscium fishelsoni (see Figure 11.16 page 316). It was presumed to be a protozoan. in 1993, researchers determined that Epulopiscium was actually a gram-positive bacterium. Why do you suppose this organism was initially identified as a protozoan? What evidence would change the classification to bacterium?

* Probably because it

1. Is gigantic for a bacterial cell. 80um (almost a milimeter)

2. Has strange morphological features, like invaginations, vesicles, and tubules.

3. Reproduces strangely.

* But they performed rRNA analysis by Pace, et...