These questions are to get you thinking and synthesizing; there is no guarantee that any of these questions in their present form will appear on a quiz or test, although the content reflected in these questions will.

1. Illustrate & discuss the fluid mosaic model of a membrane.
2. What constitutes a transport system in the bacterial plasma membrane? What is meant by active transport of a solute? Why do most bacteria have a need for active transport systems? What is the fundamental distinction between transport of a solute by active transport vs. group translocation? Is there any advantage in the latter process?
3. Describe the similarities & differences between the cell walls of Gram-positive and Gram-negative bacteria.
4. What accounts for the rigidity and strength of bacterial cell walls?
5. What is lysozyme? Where is it found in nature? What is the effect of lysozyme on bacteria and what is its mechanism of action?
6. Penicillin is known to be most effective against Gram-positive bacteria that are actively multiplying. Why is this so? Many Gram-negative bacteria are inherently resistant to natural penicillin. Why is this so?
7. Identify these structural components in the cell wall or cell "envelope" of certain bacteria: peptidoglycan sheet, lipopolysaccharide layer, lipoprotein, teichoic acids, interpeptide bridge. Identify these chemical components: N-acetylmuramic acid, D-glutamate, D-alanine, diaminopimelic acid, L-lysine, pentaglycine bridge, Lipid A, ketodeoxyoctonoic acid.
8. Identify the location and function each of these components of the outer membrane of E. coli: phospholipid, LPS, Lipid A, O-polysaccharide, porins, and Braun lipoprotein. What is the function of the outer membrane to the bacterium?
9. What arrangements of flagella are found on bacteria? Is there any taxonomic value in determining the presence or absence of flagella, or in knowing flagellar arrangements? Can you see bacterial flagella with a light microscope? How could you demonstrate that a bacterium has flagella? How could you demonstrate that flagella are responsible for bacterial swimming movement? What are the differences between bacterial flagella and the flagella of eukaryotic cells?
10. Describe the ultrastructure of the bacterial flagellum as revealed by electron microscopy. Explain how the flagellum operates to impart movement to a bacterial cell. What are chemotaxis, phototaxis, aerotaxis, and magnetotaxis, and what do these processes have to do with flagella?

1. Define anabolism, catabolism and metabolism.
2. Define oxidation and reduction. Describe the crucial role played by coenzymes in biological oxidation-reduction processes.
3. What are the organic electron carriers used in biological systems? Give three examples of electron carriers in electron transport systems and indicate their oxidized and reduced forms. What is the most commonly used soluble electron carrier in cells?
4. What is NAD (NADP)? How does it function in fermentation and respiration?
5. Describe the role of ATP in energy exchanges within the cell.
6. Distinguish between substrate level phosphorylation and electron transport level phosphorylation.
7. What is the relationship between a membrane-bound electron transport system and generation of proton motive force across the membrane, which can lead to the synthesis of ATP? What is the role of protons on one side of the membrane and what is the nature and function of membrane-bound ATPase?
8. Differentiate between fermentation and respiration.
9. Why is pyruvate a key compound in the metabolism of carbohydrates? List several of the end products resulting from bacterial fermentation of glucose and name some important groups of bacteria that form the end products.
10. How does a respiring heterotrophic bacterium generate a proton motive force? How can this force be used to synthesize ATP? How can fermentative heterotrophic bacteria generate a proton motive force? How can a proton motive force be used directly to do cellular work?
11. The redox potential (Eo) of a half reaction indicates the tendency of the oxidized (reduced) substance to accept (donate) electrons. Do large positive redox values indicate a great or slight tendency to accept electrons? Do low negative redox values indicate a great or slight tendency to donate electrons?
12. Describe the flow of electrons in the electron transport system of an aerobic respirer. What are the major classes of coenzymes and enzymes in the respiratory chain?
13. How many ATP can theoretically be produced from the aerobic respiration of glucose via (a) substrate level phosphorylation and (b) electron transport level phosphorylation? What proportion of the total energy available in glucose is captured by the cell?
14. Compare fermentations to aerobic respiration with respect to (a) the amount of energy released from the energy source (e.g. glucose), (b) the compound that serves as a terminal electron acceptor and (c) the mechanisms of ATP synthesis that are involved.
15. Much more energy is available from glucose respiration than from glucose fermentation. However, the laws of thermodynamics state that energy is neither created nor destroyed. Where is the energy in the glucose molecules that was not released in the fermenting organism (versus the respiring organism)?
16. Work through the energy balance sheets for fermentation and respiration and account for all sites of ATP synthesis. Some organisms can obtain about 15 times more ATP when growing aerobically on glucose than anaerobically. What accounts for this difference?
17. In aerobic respiration, O2 serves as the ultimate electron acceptor. To what substance is O2 always converted as it accepts electrons?
18. Name four substances that are used by certain bacteria as terminal electron acceptors in the process of anaerobic respiration. How does this process differ from aerobic respiration? What is the biological importance of anaerobic respiration?
19. A bacteriologist has isolated a mutant organism that is blocked in glycolysis between acetaldehyde and ethanol. The organism is no longer able to grow anaerobically on glucose but is still able to grow when O2 is present. Give a possible biochemical explanation for this observation.
20. A bacteriologist hopes to prevent the growth of obligately-respiratory (non fermentative) pseudomonads by incubating his/her enrichment cultures in the absence of O2. The attempt fails; after incubation the culture is teeming with Pseudomonas species. Give a possible biochemical explanation for this observation.
21. Cellulose, the principle component of plant cell walls, is the most abundant organic compound in the world. It is a largemolecular weight polymer of glucose. Think about a bacterium in the soil that could utilize cellulose aerobically as a sole source of carbon and energy for growth. Where and how would cellulose utilization begin? What would happen to the carbon in cellulose? What metabolic pathways and mechanisms would the bacterium have?