Review Questions-1 General concepts, history What was the technique that Carl Woese used to identify another domain to classify m/o in? How did Pasteur help resolve the debate on spontaneous generation? What is the difference between Pasteurization and Tyndallization? What kinds of organisms survive pasteurization? How is pasteurization different from sterilization? What was the contribution of Carl Woese to the classification of organisms? What domains did Woese divide microorganisms into? How did his research revolutionize the phylogenetic tree of microorganisms? Why did Carl Woese choose rRNA as a molecule that could be studied for phylogeny? What other molecules could be used instead? What surprising results did his study bring up? Know the names and characteristics of some organisms (2 large, 2 typical and 2 unique in some way other than the large size) from the table in “BIG BACTERIA”. What is the importance of Koch’s postulates? What are the molecular Koch’s postulates? How do they reinforce the original criteria that Koch put forward in determining the causal relationship between microorganisms and disease? Why was the development of solid media a boon to microbiology? Why did Agar quickly overtake gelatin as the most favored solidifying agent? Microscopy and staining Compare and contrast between light microscope and electron microscope (both TEM and SEM). Know the resolutions limits, and magnifications achieved by each. Since electron microscopes have higher magnification as compared to light microscopes, can you use it to observe a moving paramecium? What other kinds of microscopy can you use to observe such a specimen? What are the different kinds of electron microscopes? Which kind would you use to study: a. internal structure of the mitochondria b. morphology of a bacterial cell Why is Gram staining considered a differential staining technique? Know the procedure of Gram staining. What is the current understanding about why Gram negative organisms do not retain the primary stain? Why is it difficult to stain Mycobacterium tuberculosis using Gram staining technique? Acid-fast staining is used specifically on bacterial strains that contain __________ in their cell wall.Cell Structure and Function What are the three basic shapes of bacterial cells? Do all cells have rRNA? What is the purpose of rRNA? What is the ‘typical’ size of a prokaryotic cell? Compared to the ‘typical’ size, how many times is Epulopiscium fishelsoni bigger in volume? What is the theoretical minimum genome size of a free-living organism? What are Nanobacteria? Would you expect Nanobacteria to be free-living cells? Explain. How are big bacteria like Thiomargarita namebiensis and Epilopiscium fishelsoni able to survive as prokaryotes in spite of their huge sizes? Know the functions of Prokaryotic and Eukaryotic structures. In which way are the prokaryotic ribosomes similar to the eukaryotic ribosomes and in which way are these different? What is nucleoid? What are plasmids? What is the major chemical component that differs in the plasma membrane of prokaryotes and eukaryotes? What is its function in the membrane? What function does cholesterol have in the cell membranes of eukaryotes? What do bacteria have instead of cholesterol in their membranes? What makes the plasma membrane amphipathic? What makes the plasma membrane selectively permeable? What is the MAIN difference between a eubacterial and an archaebacterial plasma membrane? Give two distinguishing characteristics of the Archael membranes. What are the similarities and differences between passive diffusion, facilitated diffusion, active transport and group translocation? What is passive transport? What kinds of molecules enter the cell through this kind of transport? Do you think that amino acids are passively transported into the cell? What is facilitated diffusion? How is it different from active transport? Why do microorganisms normally take up nutrients using transport proteins or permeases? What advantage does a microorganism gain by employing active transport rather than facilitated diffusion? How are molecules transported by the ABC transport mechanism? How does the PTS transport system function? In what way is this system different from the ABC system? Which one of the transport systems is defective in patients having cystic fibrosis? Compare (in a table) the similarities and differences between passive diffusion, facilitated diffusion, ABC transport and group translocation. Prokaryotic cell wallSketch a Gram + ve and a Gram - ve cell wall. Highlight the characteristic feature(s) of each. How do the Mycoplasmas differ from the G + ve and G - ve cells? What is unique about the cell wall of Mycobacterium? What is periplasmic space? What is the nature of the proteins that are present in the periplasmic space? What are the major components of the cell walls of: Plants, Fungi, Eubacteria, Archaebacteria What is the advantage in having D amino acids in the cell wall? What structure accounts for the negative charge and for toxicity in G +ve cells ? Know in detail the structure of Gram positive and Gram negative cell walls. What is the difference in the type of cross-linking found in the peptidoglycan of most Gram positive and Gram negative bacteria? What is characteristic of the third amino acid in the peptidoglycan subunit? What other amino acid can take the place of DAP (or lysine)? Why? What are the components of LPS? What is the function of O antigen? What makes LPS an endotoxin? How is the outer membrane different from the plasma membrane? Why are Archaebacteria resistant to the action of lysozyme? What is the major difference between the cell wall of Archae and that of Eubacteria? The polymerization of the new subunit of the peptidoglycan to the existing cell wall occurs outside the plasma membrane. Where does the energy for the transpeptidation step come from? What is the function of bactoprenol? What are autolysins? Why are they important? What is the role of autolysins in the synthesis of bacterial cell walls? Mention the different patterns of cell wall formation. What is the role of penicillin binding proteins in cell wall synthesis? Describe the role of