Green Fluorescent Protein (GFP) is a protein that emits

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Green Fluorescent Protein (GFP) is a protein that emits bright light in the green segment of the visible spectrum upon exposure to blue light. Its properties were first researched in 1962 by Osamu Shimomura, a Japanese scientist who studied the bioluminescence of Crystal Jellyfish, or Aequorea victoria. Shimomura discovered that such biologically-generated glow is produced when the jellyfish produces calcium ions. The ionized calcium is absorbed by a protein that produces blue luminescence upon binding with calcium, called Aequorin. Crystal jellyfish typically have nodes of Aequorin on the rim of their umbrella, but Shimomura found that these photosensitive organs are composed of another type of protein. The blue light resulting from the Aequorin calcium binding is received by the protein now known as GFP. Since GFP's major excitation peak is at a wavelength of 395nm, or in other words - blue light, it becomes active and emits visible light whose peak is at 509nm, i.e., green light. This creates a circle of greenish light around the jellyfish's umbrella. Shimomura et al received a Nobel Prize in Chemistry for the discovery and development of GFP.

GFP has numerous uses in cellular and molecular biology, most commonly as a reporter of expression. In layman's terms, Green Fluorescent Protein is used as an indicator to the activation of certain genes into which it is spliced. This mean that only the cells in which those specific genes are activated will fluoresce green under a blue light. This has been tremendously useful in mapping out the connection between DNA strings in genes and the biological systems which they control.

Another field where GFP was found to be profoundly useful is fluorescence microscopy. Before the discovery of GFP and its derivatives, fluorescent microscopists used synthetic fluorophores to dye the target sample. However, such fluorophores were found to be highly phototoxic, as the light they emitted was transferred to oxygen molecules in the cells under examination. This provoked the creation of oxygen radicals that could kill a living cell in seconds. GFP has proven to be dramatically less phototoxic, thereby revolutionizing this field of science.

1) The contribution of the discovery of GFP to fluorescence microscopy is regarded by the author with:
a) subtle dismissal
b) scientific zeal
c) explicit appreciation
d) blunt disregard
e) reluctant acknowledgement

Pls explain your pick.

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by jarvis » Tue Dec 27, 2011 5:17 am
I zeroed-in to options (b) and (c).

I feel the answer would be option (b).

My Reasoning - In the last paragraph a lot of scientific detail is provided, while explaining the contribution of GFP on fluorescence microscopy. Adjectives in the paragraph led me to reason that there was a 'zeal' in the explanation.

Let me know your thoughts.

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by happymanocha » Fri Dec 30, 2011 10:38 am
IMO : B

Explanation: Last sentence,thereby revolutionizing this field of science,of the paragraph 3 explicitly says about the revolution in this field of science.

What is the OA?

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by patanjali.purpose » Fri Dec 30, 2011 12:06 pm
OA - C

It will be great if anyone can share his insight.

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by avik.ch » Wed Jan 11, 2012 1:45 am
patanjali.purpose wrote:OA - C

It will be great if anyone can share his insight.
Structure of the passage :

1 . GFP - defination.
Discovery by X --- how ??
Viewpoint : neutral

2. Application of GFP in cellular and molecular biology.
tone : positive ( tremendously useful )

3. Application of GFP in fluorescence microscopy
tone : positive ( profoundly useful , along with some benefits)

Viewpoint : neutral
mainpoint : discovery of GFP and its application in cellular and molecular biology and fluorescence microscopy

1) The contribution of the discovery of GFP to fluorescence microscopy is regarded by the author with: from our structure we know that this has to be positive. So we can directly eliminate - a, d and e. We have to be localized now, concentrating only on the final paragraph.

b - scientific zeal - here the author is not mentioning anything related to any scientific discovery, its just telling us how the introduction of the GFP in the field of fluorescence microscopy has been benefitial. Moreover, "zeal" is a word used for passion for something.

if the passage told us something as : some discovered X, and he was really attracted towards this from childhood .... and finally he succeded after repeated failiure - here "zeal" is a perfect word.

C - explicit appreciation : here the author is just appreciating a fact. So this is the correct one.

Hope this helps
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by ArunangsuSahu » Wed Jan 11, 2012 10:54 pm
The last line of the passage differentiates between (B) and (C)

GFP has proven to be dramatically less phototoxic, thereby revolutionizing this field of science.


(C) is the answer