This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Movement of protein from nucleus to cytoplasm can be seen by 
Select and explain. 
A. FISH, B. FRAP, C. Confocal microscopy, D. Electron microscopy
B: FRAP
Answer: B: FRAP 
Explanation: B i.e. FRAPFRAP (fluorescence recovery after photobleaching) primarily measures rate of lateral diffusion of lipids and it can be used to investigate diffusion of biological macromolecules (such as proteins etc) including lateral diffusion in the plane of membrane and movements into & out of nucleus.- FRET is used to visualize biochemistry of living cells such as to measure cAMP and activity of PKA.AFM (atomic force microscopy) is used to yield 3D contour map of membrane (surfaces) and visualize membrane proteins (eg microdomains or rafts etc)