Understanding Molecular Biology with simple Examples

Today we discussed how protein synthesis takes place, the questions came what is mRNA? What message is mRNA bringing? @Sawaha said the are carrying information. @Hitesh gave an example, suppose your mom is outside, and your dad wants to cook food and he doesnt know the recipe, and their mobile phone is not with them how will the message pass? What can be the best way? @Swaha said, someone can act as a messanger and pass on the information from father to mother.

The same way mRNA is a messenger which passes on the information from DNA to form proteins.
The example of PER (Period) protein was taken as an example.
Connecting it with sleep, in fruit flies Per protein is produced during day time. In day time, in the presence of light, the sunlight affects the Per gene, which produces Per mRNA which forms the Per protein, which is produced in day time.

The question was but we cant see it. How could we see it? Can we see it with Green fluorescent Protein (GFP)?
It was said that PER gene can be tagged with GFP gene, so whenever PER protein is produced, GFP will show fluorescence there indicating presence of PER protein. GFP fused PER protein can be helpful to view at what time and in which location PER protein is produced in fruit fly.