Final answer:
Northern Blot analysis allows researchers to detect and quantify specific RNA (often mRNA) in a given sample by using gel electrophoresis and a labeled nucleic acid probe. It can assess gene expression levels in the WKYKID samples as compared to other cell extracts, indicating how actively a gene is being expressed.
Step-by-step explanation:
The Northern Blot technique is a molecular biology method used to study gene expression by detecting RNA (or isolated mRNA) in a mixture of RNA. Northern blotting, similar to Southern blotting, involves the separation of RNA fragments by gel electrophoresis, followed by the transfer of these fragments to a nylon membrane. The transferred RNA is then probed with a complementary DNA or RNA probe that has been labeled with a radioactive or fluorescent tag to allow for visualization.
In the context of the question, the student's inquiry is focused on the results from a Northern Blot experiment looking at extracts from different cells. Sample from WKYKID would refer to one of the lanes in an electrophoresis gel where RNA fragments from WKYKID cells have been separated. By using a specific probe for SA cDNA, researchers can determine if the SA gene is being expressed in WKYKID cells and compare the levels of expression against other cell extracts, visualized as bands on the blot.
An important application of Northern blot is to assess the presence and quantity of specific mRNA sequences, indicating gene expression levels in different samples or conditions. In such experiments, the molecular weight marker in the first lane serves as a standard for estimating the sizes of the RNA transcripts detected. Northern blotting is a crucial technique for studying gene expression patterns and understanding cellular responses to various stimuli or in different disease states.