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.
Plagiarism (use of others words, ideas, images, etc. without citation) is not to be tolerated and can be easily avoided by adequately referencing any and all information you use from other sources. In the strictest sense, plagiarism is representation of the work of others as being your work. Paraphrasing other's words too closely may be construed as plagiarism in some circumstances. In journal style papers there is virtually no circumstance in which the findings of someone else cannot be expressed in your own words with a proper citation of the source. Refer to: The Bates College Statement On Plagiarism and a Guide to Source Acknowledgment .) If you are unclear about what constitutes plagiarism, please confer with your instructor.