 While working in the molecular biology laboratory, we extract different kinds of biological molecules. In order to analyze the expression of genes implicated in different disorders, or the detection of RNA viruses like coronavirus or any other downstream technology, we first have to extract the RNA. So there are different methods to extract the RNA, like the KIT method, trisol method, or the manual method. But the trisol method is the most commonly used method while performing the extraction of RNA in molecular biology laboratory. So in this practical, we will demonstrate that how to extract the RNA from blood using trisol method. Let's perform the experiment. The major reagents and materials required for RNA extraction are blood, trisol reagent. Trisol reagent is a light sensitive chemical and it preserves the integrity of RNA. Next is chloroform, isopropanol, ethanol, and finally, nucleus free water. First of all, 250 microliter blood sample will be taken in Appendorf tube. After the addition of blood sample, 750 microliter of trisol reagent will be added. Once you will add the trisol reagent, Appendorf tube will be inward to mix the samples homogeneously. Next, 200 microliter of chloroform will be taken and add in the Appendorf tube. The function of chloroform is to separate the RNA from other cell contents and proteins. After the addition of chloroform, vortex the Appendorf tube for one minute. Next step, we will centrifuge the sample at 13,000 rpm for 15 minutes at 4 degree Celsius. After the completion of centrifugation, you will take out the Appendorf tube. As a result of centrifugation, you will observe three layers. Upper is the aqueous phase that contains the RNA. Second is the interface and third are the impurities. Now we will transfer the aqueous phase to a new Appendorf tube. It should be noted that the tip of the pipette should not touch the interface. You will just pick the aqueous phase that contains the desired RNA molecule. After the transfer of aqueous phase to the new Appendorf tube, we will add the equal volume of isopropanol in the Appendorf tube to precipitate the RNA. Similarly, after the addition of isopropanol, we will again centrifuge the sample at 13,000 rpm for 15 minutes. After centrifugation, you will observe the pallet in the bottom of the tube and you will discard the supernatant preventing the pallet. Now we will wash the RNA pallet with ethanol to remove the impurities. So 5 to 600 microlitre of 70% chilled ethanol will be added into the Appendorf tube. After the addition of ethanol, we will again centrifuge the sample at 13,000 rpm for 15 minutes. After the centrifugation, discard the supernatant, we will add nucleus free water into the Appendorf tube after air drying the ethanol. The nucleus free water will protect the RNA. After the addition of nucleus free water, we will store the RNA at minus 80 degrees Celsius.