Questions: A patient tells the nurse that karyotyping is going to be conducted and wants to know what this test is designed to do. Which response by the nurse would be accurate?

The answer is the second one: "Karyotyping is a test used to examine the visual appearance of chromosome structures and number."

Explanation for each option:

1. "Karyotyping make a fluorescent tag on probe signals when the DNA sequence has been identified":

   • This statement is incorrect. Karyotyping does not involve fluorescent tagging of probe signals. This description is more aligned with techniques like Fluorescence In Situ Hybridization (FISH).

2. "Karyotyping is a test used to examine the visual appearance of chromosome structures and number":

   • This statement is correct. Karyotyping involves examining the size, shape, and number of chromosomes in a sample of cells. It is used to identify chromosomal abnormalities such as extra or missing chromosomes, or structural changes in chromosomes.

3. "Karyotyping allows for detection of single-gene sequencing":

   • This statement is incorrect. Karyotyping does not detect single-gene sequencing. Single-gene sequencing is typically done using methods like Sanger sequencing or next-generation sequencing (NGS).

4. "Karyotyping rapidly detects the chromosome number and targets specific DNA sequences":

   • This statement is partially correct but misleading. While karyotyping does detect chromosome number, it does not specifically target DNA sequences. It is more about the overall structure and number of chromosomes rather than specific sequences.

Summary: Karyotyping is a test used to examine the visual appearance of chromosome structures and number, making the second option the accurate response.