ZI6th Sm.
)-MicrohiolozyHDSEBKS
2023
MICROBIOLOGY HONOURS
Paper : DSE-B-3
(Instrumentation and Biotechniques)
Full Marks : 50
The figures in the margin indicate full marks.
Candidates are required to give their answers in their own words
as far as practicable.
Answer question no. 1 and any three questions from the rest (2-6).
1. Answer any ten questions : 210
(a) What is the function of staining in light microscopy?
(b) What is RCF? What is its unit?
(e) What the role of monochromator in a
spectrophotometer?
Ud) Explain the importance of stacking gel in SDS-PAGE.
e) Why is ethidium bromide used to visualise nucleic acid bonds in an
agarose gel?
A) State the significance of conjugation in chromophores.
(g) What is numerical aperture?
(h) Define auxochrome.
(i) State two applications of phase-contrast microscopy.
() What is UPLC?
ky Give one example each of a cation exchanger and an anion exchanger.
A) Why is glycerol added to gel loading dye?
(m) Derive the unit of molar extinction coefficient.
(DY What do you mean by hypsochromic shift and bathochromic shift?
(0) What is capillary gel electrophoresis? State its application.
2.Aa) Why are protein gels run vertically?
(b) What are the two dimensions of seperation in a
protein 2D electrophoresis? Can he order of
running the two dimensions be reversed? Explain.
(c) What type of gel electrophoresis should be performed to resolve the
your answer in each case.
following molecules? Justify
(i) Short oligonucleotides
(ii) Subunits of a multimeric protein.
(d) You wish to detect an enzyme by virtue of its activity after electrophoretic separstion Whal knd
of gel will you run?
Please Turs Over
Z(6th Sm,)-Micobiolog-H/DSE-B-3/CBCS (2)
3. (a) What are the factors responsible for deviation in Lambert Beer's
law?
(b) How can we get useful infornation about a protein's structure from its UV absorption specirurm
by changing the polarity of the solvent?
(C) State the range of wavelengths associated with near-UV and far-UV regions. Why are these
regions called so?
(d) Calculate the absorbance of 0.03 mM of adenine in a l cm path length covette. Giv en molar
extinction coefficient of adenine is 13,300 at 260 nm. 3+2-12-1-2
4 a) What do you mean by resolution of amicroscope? Write down the correlation between wavelength
of light and resolution of microscope.
(b) Differentiate between bright field and dark field microscope.
(c) What is the importance of dichroic mirror in the construction of fluorescence microscope?
(d) Explain why living samples are not analyzed using TEM. (1-2-3+2-2
5. (a) What type of centrifugation technique would you use to separate cytosolic organelles from a tissue
homogenate? State its principle.
(b) State the differences between fixed angle rotors and swinging bucket rotors.
(c) What is isopycnic centrifugation? State one application of it.
(d) How can one determine the molecular weight of a substance using Svedberg's equation?
2-2-2-l-2%
6. (a) What is ascending paper chromatography? Briefly explain the process.
(b) Differentiate between normal phase and reverse phase liquid chromatography.
(c) Draw the chromatograms for the following types of separations in gel filtration coiumn
chromatography :
(i) two analytes showing complete resolution
(i) two analytes showing incomplete resolution.
(d) Differentiate between the techniques of gradient and isocratic elution in column chromatography.
3-2-2-3
