We are listing out some of the CSIR December 2014 Exam Doubtful Questions and their answers?
If you have any doubtful questions, please use below comments section.
Finally, you can doubtfull questions to submit to CSIR (latest by 28th January 2015).
Please spend time and will help CSIR Aspirants….
Booklet A (Doubtful Questions/Answers).
24. Reaction products inhibit catalysis in enzymes by
a. Covalently binding to the enzyme
b. altering the enzyme structure.
c. occupying the active site. [CSIR Answer]
d. form a complex with the substrate
67. Which of the following statements is INCORRECT for fluorescence in situ hybridization (FISH) technique?
a. A fluorescence confocal microscope is used to detect signal
b. A labeled sequence of nucleotides used
c. Specific fluorescence tagged antibodies are used. [CSIR Answer]
d. A stringent washing step is essential to remove appearance of non specific signal
68. In an experiment to detect a new protein in fixed cells, no secondary antibody tagged with fluorescence dye
is available. What should be the best choice out of the following to detect the protein?
a. Protein A-FITC [CSIR Answer]
b. Protein A-Sepharose
c. Biotin-FITC
d. Avidin –FITC
74. Two homologous proteins were isolated from a psychrophile (P) and a thermophile (T). The purified proteins were subjected to denaturation, protease digestion and circular dichroism (CD). Following observations were made
A. The CD spectra of P and T proteins are identical
B. Their amino acid composition is 95% identical
C. T and P are equally susceptible to proteolysis in the presence or absence of reducing agent
D. T has higher midpoint of thermal denaturation than P
The reason for enhanced stability in T is due to
a. Altered secondary structure
b. Increased number of disulfides in T
c. Increase in water of hydration
d. Increase in number of salt bridges [CSIR Answer]
88. A promoter deletion study was done in order to determine the binding sites for a transcription factor on the promoter, which is activated on treatment with the drug 'X'. The following constructs were made
Luciferase assay revealed the following results
The following statements can be made.
A. Region between -1800 and -1210 contains a binding site for the activator.
B. Region between -868 and -1210 contains a binding site for a repressor.
C. Region between -868 and -432 contains a binding site for a repressor.
D. Region between -1210 and -868 contains a binding site for the activator.
Which of the above is/are true?
a. A and C
b. B and C
c. A and D [CSIR Answer]
d. B only
112. At 17 years, a 7 feet tall human was diagnosed with gigantism caused by pituitary tumor. The condition was surgically corrected by removal of the person's pituitary gland. Doctors advised hormonal therapy. The possible hormonal therapies that would be required for survival are
A. Thyroid hormone
B. Glccocorticoid
C. glucagon
D. Growth hormone
E. Insulin
Which one of the following combination can be used?
a. A and B only [CSIR Answer]
b. B and D only
c. A, B and D
d. A, C and E
More questions will be add soon (updated)
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7 Comments
For question no. 24 booklet, CSIR answer is absolutely correct.
ReplyDeleteIn case of product inhibition, product of an enzymatic reaction binds to the active site and inhibits its activity. There's no doubt in that.
Dear Anonymous (Great),
ReplyDeleteWhy product will bind to enzyme? if binds also why will it binds to active site. May be other than active site.
As per the choices given in the question, I'll explain.
ReplyDeleteproduct doesn't forms a complex with substrate because its the product inhibition to enzyme (nothing to do with substrate; refer to end product inhibition topic) so option D ruled out. For option A, had it been a covalent binding with enzyme then all the biochemical reactions in our body which involves end product inhibition would not have restored on removal of product, which is not true, so option A gone. and left option B same explanation;
altering structure of enzyme or covalent modification comes under irreversible inhibitors. whereas in GENERAL product-enzyme is reversible i guess.
So option C left. the most appropriate one
Those Na and K ions
ReplyDeletethat do change places across the membrane during an action
potential are eventually pumped back by the Na /K -ATPase.
Even if the Na /K -ATPase is inhibited, a neuron can often
continue to fire thousands of impulses before the ionic gradients
established by the pump’s activity are dissipated.
Once the membrane of a neuron is depolarized to the
threshold value, a full-blown action potential is triggered without
further stimulation. This feature of nerve cell function is
known as the all-or-none law. There is no in-between; subthreshold
depolarization is incapable of triggering an action potential,
whereas threshold depolarization automatically elicits a
maximum response. It is also noteworthy that an action potential
is not an energy-requiring process, but one that results from
the flow of ions down their respective electrochemical gradients.
Energy is required by the N /K -ATPase to generate the
steep ionic gradients across the plasma membrane, but once
that is accomplished, the various ions are poised to flow through
the membrane as soon as their ion channels are opened.
The movements of ions across the plasma membrane of
nerve cells form the basis for neural communication. Certain
local anesthetics, such as procaine and novocaine, act by closing
ion channels in the membranes of sensory cells and neurons.
As long as these ion channels remain closed, the affected
cells are unable to generate action potentials and thus unable
to inform the brain of events occurring at the skin or teeth.
Doubtful question, part A Q.93... (CSIR ans 2)
ReplyDeleteQ 88 is correct
ReplyDeletepolyandry benefit for female...part-c...csir asked which is not coorrect from polyandry benefit....here all options are correct but csir gives the 3rd one.
ReplyDelete