Determination of protein concentration in a simple is a important step in every analysis. Today different methods for quantitation of protein are developed, but classic spectrophotometric methods, such as Biuret, Lowry i Bradford method, are the most often used in biochemical and medical research. All methods have some advantages and disadvantages, and they are based on reaction of metal ions and dye with proteins to give caracteristically coloured product. Measurment of absorbance are preformed at wavelenght of 540 nm for Biuret method, and at 595 nm for Lowry and Bradford method. The aim of this study is determine and compare sensitivity of Biuret, Lowry i Bradford method fod determination of concentration of proteins, which are isolated from human cervical carcionoma cells, also known as HeLa cells. Concentration of proteins are also determined by modified Bradford method, where for preparation of Bradford reagent, CBB R-250 are used instead of CBB G-250. The highest concentration of proteins are determined by modified Bradford method, but the lowest concentration are determined by use commercial Bradford reagent. This thesis also contains a part with teaching methods on high school level including printed preparation for lesson „Aminoacids and proteins“, corresponding working papers and two experiments for group work. This lesson is prefomed through combination of a lecture and group work (students are divided into 4 groups and they preform two experiments).