The third paragraph of the body should contain the weakest argument, weakest example, weakest illustration, or an obvious follow up to the second paragraph in the body. The first sentence of this paragraph should include the reverse hook which ties in with the transitional hook at the end of the second paragraph. The topic for this paragraph should be in the first or second sentence. This topic should relate to the thesis statement in the introductory paragraph. The last sentence in this paragraph should include a transitional concluding hook that signals the reader that this is the final major point being made in this paper. This hook also leads into the last, or concluding, paragraph.
You may want to identify certain types of equipment by vendor name and brand or category (., ultracentrifuge vs. prep centrifuge), particularly if they are not commonly found in most labs. It is appropriate to report, parenthetically, the source (vendor) and catalog number for reagents used, ., " ....poly-L-lysine (Sigma #1309) ." When using a method described in another published source, you can save time and words by providing the relevant citation to the source. Always make sure to describe any modifications you have made of a standard or published method.