German physicist Jan Hendrik Schön of Bell Labs claimed in 2001 that he had produced a molecular scale transistor. Others scientists noted that his data contained irregularities. Attempts to perform experiments similar to Schön’s did not give similar results.

Which of the following Aspergillus species cause aspergilloma? (a) A. fumigatus (c) A. candida (b) A. ochraceous (d) A. niger  Casual agent of desert rheumatism is (a) Candida albicans (c) Coccidioides immitis (b) Claviceps purpurea (d) Aspergillus candidus Pneumocystis carinii invades the cells of (a) Skin (c) Both of them (b) Lungs (d) None of them 5.

Use the Jukes-Cantor distance and the Neighbor Joining programnj to construct trees for the following simulated sequence data in seqdata.mat. Compare your results with that produced by other methods in Problems 5.2.9 through 5.2.12 of the last section. How has whether a molecular clock operated in the simulation affected the results? a. a1, a2, a3, and a4 (molecular clock) b. b1, b2, b3, b4, and […]

Briefly comment on River’s postulates. What is their significance in virology? Describe the most important discoveries you think have helped in the development of microbiology. Refractive index of immersion oil is (a) 1.0 (c) 2.0 (b) 1.5 (d) None of these Fluorescent microscope uses a (a) Mercury vapour arc lamp (c) Any one of the above (b) Halogen lamp (d) None of the above 4.

Discuss the role of microorganisms in the biogeochemical cycling of nitrogen. Describe the process of bioleaching. Name at least ten microorganisms, which are implicated in bioleaching. Define the following terms. Decomposer Nitrification Thermocline Eutrophication Denitrification Hypolimnion Mineralisation Nitrogenase Epilimnion

Briefly describe the Calvin–Benson cycle. 10. Describe the biosynthesis of amino acids and glycogen in microbial cells. Compare the gluconeogenic and glycolytic pathways. What is meant by exergonic and endergonic reaction? Explain why fermentation is a less efficient process for obtaining energy than aerobic respiration.

Describe briefly the principle, working and major advantages of using phase contrast microscope. Give the principal uses of the following types of microscopy: (a) Scanning tunneling microscopy (b) Atomic force microscopy (c) Scanning acoustic microscopy (d) Differential interference contrast microscopy

A. Use a computer program such as sir or twopop to explore the SI S model. Vary the parameters _, _ , N, S0, and I0. Describe your observations. B. Investigate the SI S model by doing the following: a. Solve for all equilibria (S* , I *). Are these biologically reasonable? An equilibrium with I * 0 represents the endemic occurrence of a disease. […]

Make a list of the significant contributions made by Robert Koch to the field of microbiology. What do you consider to be his most significant contribution? How did Louis Pasteur’s experiments disprove spontaneous generation? Why do you think viruses are not included in the five-kingdom system?

Nystatin is used to control (a) Bacteria (c) Fungi (b) Protozoa (d) Virus Which of the following statement is true? (a) Vancomycin is produced by Bacillus subtilis. (b) Bacitracin is produced by Bacillus subtilis. (c) Cyclosorine is produced by Bacillus subtilis. (d) Cephalosporine is produced by Bacillus subtilis.

A sewer of diameter 1m is to be laid along a road with self-cleaning velocity as 90 cm/sec. Find the gradient of the sewer line to achieve the said velocity considering the sewer running half filled. Assume Bazin’s constant = 0.30. How is the center line of sewer marked on the ground? How is the leakage of sewer tested?

One approach to preventing disease spread is to simply quarantine infectives. Suppose a disease is modeled well by the SI R equations of the text, but a society decides to attempt a quarantine program, preventing a fraction q of the infectives from having contacts with susceptibles. Only 1 _ q of the infectives will be able to spread the disease. a. How should the mass […]

Write short notes on the following eukaryotic microorganisms: (a) Diatoms (b) Euglenoids (c) Plasmodial slime moulds (d) Dinoflagellates (e) Ciliated protozoa (f) Green alga (g) Yeasts (h) True slime moulds 8. Define the following: (a) Dimorphism (e) Syngamy (b) Coenocytic (f) Holocarpic (c) Symbiosis (g) Eucarpic (d) Schizogony (h) Phytoplankton

Name the most common protozoa causing epidemic water-borne diarrhoeal disease? Comment on its diagnosis and treatment. How do infections caused by Balantidium coli occur? Briefly describe methods of preventing and controlling this infection. In what ways does Toxoplasma affect human health?

In what ways does the immunity operon of phage regulate lysogeny? Describe the unique steps of phage T4 adsorption on a bacterial cell surface. What is a prion? In what way does a prion appear to differ fundamentally from viruses and viroids? What is the function of satellite viruses? Explain the process and application of phage typing.

List different kinds of radiations that are destructive to microorganisms. Why is ionising radiation more effective than ultraviolet radiation for sterilisation of food products? What is a food preservative? Discuss the commonly used food preservatives. Describe the process of pasteurisation. Why is it necessary to refrigerate milk that has been pasteurised?

The Jukes-Cantor distance is an estimate of the number of mutations that occurred per site over the course of one sequence evolving from another. A simpler estimate for this number is just p, the proportion of sites that have changed from the initial to final sequence. a. Explain why multiple mutations at the same site would cause p to be less reliable. Does it give […]

How is translation inhibited by each of the following: (a) Chloramphenicol (b) Erythromycin (c) Tetracycline (d) Streptomycin Describe the mode of anti-microbial action of penicillins and sulphonamides. What are antibiotics? Give sources of ten important antibacterial antibiotics? Differentiate between bacteriostatic and bactericidal drugs.

Outline the treatment process for drinking water. What are allochthonous and autochthonous organisms? What often limits the growth of cyanobacteria in soil? How does the microbial community of fresh water differ from that of marine water? Discuss the unique role of Phanerochaete chrysosporium in mycoremediation. Name at least five more fungi which have a similar role.

Write one-sentence definition for the following terms (a) Replication (b) Alleles (c) Mutagen (d) Technology (e) Recombination (f) Inheritance Explain why the insertion of a transposon leads to mutation. Recombination in prokaryotes always involves chromosome fragments, whereas in eukaryotes it involves whole chromosomes. Explain.

Define the following (a) Definitive host (b) Intermediate host (c) Reservoir host How do infections caused by Entamoeba histolytica occur? Describe in detail the life cycle of the malarial parasite. Name one protozoan that can cause reproductive system infections. What symptoms lead you to suspect these infections?

Catabolism signifies (a) Break down of macromolecules (c) None of the above (b) Synthesis of macromolecules (d) Both ‘a’ and ‘b’ The Entner–Doudoroff pathway is found (a) Only in eukaryotes (c) Only in archaeobacteria (b) Only in eubacteria (d) Both eubacteria and archaeobacteria Lactic acid fermentation is carried by (a) Lactobacillus (c) Enterococcus (b) Streptococcus (d) All of the above

Prions are known to cause (a) Neurological disease (c) Respiratory disease (b) Gastrointestinal disease (d) Urinary disease The number of phage particles in a sample can be estimated by  (a) Immunoassay (c) ELISA  (b) Electron microscopy (d) Plaque assay  Which of the following statements is not true for viroids? (a) They are short pieces of naked RNA (b) They usually infect animals (c) They have […]

Suppose two sequences S0 and S1 have been compared, and a frequency table such as that in Table 4.1 has been produced and entered into MATLAB as a matrix F. a.       Explain why the sequence of commands. colsum=[1,1,1,1]*F, N=colsum*[1; 1; 1; 1], p0=colsum/N   will produce the fraction of sites with each base in S0. b. Give a sequence of commands to produce the fraction […]

Which of the following pair is mismatched? (a) Endospores/Schaeffer–Fulton stain (c) Flagella/Ziehl–Neelsen stain (b) Capsule/Negative stain (d) Nucleus/Giemsa stain The order of reagents used in Gram stain are:  (a) Crystal violet, iodine, alcohol, safranin (c) Crystal violet, safranin, iodine, alcohol (b) Crystal violet, iodine, safranin, alcohol (d) Crystal violet, alcohol, iodine, safranine