Which of the following best describes ELISA?

The choice that best describes ELISA, which stands for Enzyme-Linked Immunosorbent Assay, is focused on its primary function: analyzing protein concentration. This technique is widely used in laboratory settings to detect and quantify specific proteins, such as antibodies or antigens, within a sample.

In an ELISA, a sample is added to a plate coated with specific proteins that the antibodies can bind to. If the target protein is present, it will adhere to the plate. Subsequently, a secondary antibody that is linked to an enzyme is introduced, which binds to the target protein. A substrate is then added, and if the enzyme-substrate reaction occurs, it results in a measurable signal, typically a color change. The intensity of this signal correlates with the concentration of the target protein in the sample, allowing for quantitative analysis.

The other options provided describe different techniques used in biotechnology. Amplifying DNA typically involves methods such as PCR, encapsulating cells in gel refers to techniques like cell embedding or immobilization, and sequencing nucleotides deals with determining the order of nucleotides in DNA or RNA, which does not relate to the purpose or process of ELISA. Therefore, the description of ELISA as a procedure to analyze protein