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Determine the correctness or otherwise of the following Asertion (a) and the Reason (r)
Assertion : MTT assay is used to determine cell viability based on the principle of colour formation by DNA fragmentation.
Reason : MTT assay is used to determine cell viability based on the colour development by converting tetrazolium soluble salt to insoluble salt.
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- both (a) and (r) are true and (r) is the correct reason for (a)
- both (a) and (r) are true and (r) is not the correct reason for (a)
- (a) is true but (r) is false
- (a) is false but (r) is true
Correct Option: D
The MTT assay is a colorimetric assay which is used for measuring the activity of cellular enzymes that reduce the tetrazolium dye, MTT, to its insoluble formazan dye, giving a purple color. These assays measure cellular metabolic activity via NAD(P)H-dependent cellular oxidoreductase enzymes and may, under defined conditions, reflect the number of viable cells present. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole), is reduced to purple formazan in living cells. A solubilization solution (usually either dimethyl sulfoxide, an acidified ethanol solution, or a solution of the detergent sodium dodecyl sulfate in diluted hydrochloric acid) is added to dissolve the insoluble purple formazan product into a colored solution. Reduction of MTT and other tetrazolium dyes increases with cellular metabolic activity due to elevated NAD(P)H flux.
