Probe used in western blot –
**Core Concept**
The western blot is a laboratory technique used to detect specific proteins in a sample. It involves separating proteins by size using gel electrophoresis, transferring them to a membrane, and then probing with an antibody to identify the target protein.
**Why the Correct Answer is Right**
The correct probe used in western blot is an antibody or an antigen-specific antibody fragment. These probes bind specifically to the target protein, allowing for its detection and quantification. The binding of the probe to the target protein is typically visualized using a secondary antibody conjugated to an enzyme, such as horseradish peroxidase, which catalyzes a colorimetric reaction.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the type of probe used in western blot. While other types of probes may be used in other laboratory techniques, antibodies are the primary probes used in western blot.
**Option B:** This option is incorrect because it is a type of chromatography, not a probe used in western blot. Affinity chromatography is a technique used to separate molecules based on their specific binding properties.
**Option C:** This option is incorrect because it is a type of gel electrophoresis, not a probe used in western blot. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is a technique used to separate proteins based on their size.
**Clinical Pearl / High-Yield Fact**
One key point to remember when using western blot is that the choice of antibody probe is critical for the specificity and sensitivity of the assay. Using the correct antibody probe can significantly impact the accuracy of the results.
**Correct Answer:** A. Antibody.