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.

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 […]

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.

Write notes on the theory and purpose of sedimentation. Describe a rectangular type of sedimentation tank with sketch. A water supply project has to supply water to a town having population of 50,000. Design a suitable sedimentation tank with the following data: (i) Per capita demand = 150 lit/day (ii) Peak demand = 1.5 X Average demand (iii) Velocity of flow = 30 cm/min. (iv) […]

A.Recall the Leslie models of Chapter 2. The matrices used in these models are typically not Markov matrices. Why not? B. Although the Jukes-Cantor model assumes p0 = (.25, .25, .25, .25), a Jukes-Cantor matrix could describe mutations even with a different p0. Investigate the behavior of a model using a Jukes-Cantor matrix as you vary p0 by using a computer. For instance, with _ […]

A.Complete the gaps in the derivation of the formulas for dJC in the text by doing all the necessary algebra on the equation to find the formula in Eq. (4.7) for t in terms of p and _. B. The Jukes-Cantor distance formula is sometimes stated as where q is the proportion of bases that are the same in the “before” and “after” sequences. Derive […]

Why are Leeuwenhoek’s observations considered to be the first step in the development of microbiology? What is tyndallisation? Who gave this concept and which type of spore is destroyed by this process? In what ways are the contributions of Paul Ehrlich and Alexander Fleming related? Describe their important contributions.

Write short notes on: (a) Bucket-handle section (b) Egg-shaped section (c) U-shaped section (d) Horse-shoe section What are the different types of surface drains? Describe them with sketches. Describe the sewer joints with sketch. Describe the characteristics of different types of sewer materials.

A. a. Draw the single topologically distinct unrooted bifurcating tree that could describe the relationship between 3 taxa. b. Draw the three topologically distinct rooted bifurcating trees that could describe the relationship between 3 taxa. B. a. Draw all 3 topologically distinct unrooted bifurcating trees that could describe the relationship between 4 taxa. b. Draw all 15 topologically distinct rooted bifurcating trees that could describe […]

A town has a population of one lakh. A pumping unit is to be established for supplying water to the town having the following data: (i) Average water demand = 150 lit/capita/day (ii) R.L. of water in the sump well = 30 m. (iii) R.L. of reservoir = 66 m. (iv) Duration of supply = 8 hrs. (v) Distance between sump well and reservoir = […]

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.