Question

Which of the following statements about microarrays is false?A. Microarrys enable scientists to to determine the activity of thousands of genes at once.B. Microarrys use flurescently labeled cDNA molecules to identify particular genes expressed at a particular time.C. Microarrys use tiny portions of double-stranded RNA fragments from a large number of genes.

Answer 1

Answer: C. Microarrys use tiny portions of double-stranded RNA fragments from a large number of genes.

Explanation:

A DNA microarray) is a solid surface to which a collection of DNA fragments is attached. The surfaces used to fix the DNA are highly variable and can be made of glass, plastic or even silicone. It involves placing thousands of gene sequences in specific locations on a glass slide called a chip. Microarrays basically miniaturizes processes that have been used in molecular genetics laboratories for years. So, a sample containing DNA or RNA is put in contact with the chip, and it allows the detection of DNA or RNA molecules by hybridization or adhesion of the molecules on the slide. The detection of the DNA or RNA adhered is made by different labels or colors that allow them to be detected under the microscope.

Microarrays are usually used to identify genes with differential expression under different conditions. For example, to detect genes that produce certain diseases by comparing expression levels between healthy cells and cells that are developing certain types of diseases. The matching of the complementary bases between the sample and the gene sequences on the chip produces a measurable amount of light. The areas of the chip that produce this light identify the genes that are expressed in that sample.

Then, in summary, the DNA chips are used to analyze the differential expression of genes, and the levels of thousands of genes are monitored simultaneously. And it measures the level of hybridization between the specific probe (probe) and the target molecule (target), indicated by fluorescence and through an image analysis, which indicates the level of gene expression.