Explanation: The evidence that every cell in your body has DNA in the nucleus comes from various sources, such as:
• Microscopy: Scientists can use microscopes to observe cells and their structures, including the nucleus and the chromosomes that contain DNA. They can also use special techniques to stain or label DNA with fluorescent dyes or probes that make it visible under the microscope.
• Extraction: Scientists can extract DNA from cells by breaking open the cell membrane and the nuclear envelope, and then separating the DNA from other cellular components using chemical or physical methods. They can then analyze the DNA using techniques such as gel electrophoresis, polymerase chain reaction (PCR), or sequencing.
• Comparison: Scientists can compare the DNA sequences of different cells or individuals to determine their similarities and differences. They can also use DNA fingerprinting to identify individuals based on their unique patterns of DNA fragments. These methods can show that every cell in your body has the same DNA (except for some mutations or variations), and that your DNA is different from anyone else's.
However, there are some exceptions to the rule that every cell in your body has DNA in the nucleus. For example, mature red blood cells (RBCs) do not have a nucleus or DNA at all, because they lose them during their development. Other cells, such as platelets or sieve tube elements, also lack a nucleus or DNA. Additionally, some cells have extra DNA outside the nucleus, such as in the mitochondria, which are the organelles that produce energy for the cell.