DNP 810 Topic 1 Discussion Question Two
DNP 810 Topic 1 Discussion Question Two
Identify a specific disease encountered in your clinical practice or personal life. Can your patient’s understanding of DNA/RNA replication, transcription, and translation affect the management of the disease? Explain. Support your rationale with a minimum of two scholarly sources.
DNA (deoxyribonucleic acid) is one of the most important molecules in your body, and though around 99.9% of your DNA is the same as that of every other human, the 0.1% that’s different is what makes you genetically unique! This tiny biological structure is the ultimate instruction manual, containing the “recipes” for the proteins your body needs to develop and function.
id you know that in the average human cell, there is about 2m (6ft) of DNA? That’s pretty impressive, considering that even the largest cells are just over 100µm in diameter. (That’s really tiny, by the way—1µm is one millionth of a meter.)
How is all that genetic material packed into a space way smaller than the head of a pin? The short answer is a whole lot of twisting and winding. DNA wraps around protein clusters called histones to form units called nucleosomes. These nucleosomes fold into a zig-zag patterned fiber, which then forms loops.
DNP 810 Topic 1 Discussion Question Two
There are 46 separate strings of DNA in each somatic cell of the human body. Each one of these is called a chromosome. Scientists group them into 23 homologous pairs, which means that the chromosomes in each pair are similar in structure and function. The only exception to this is the 23rd pair—the sex chromosomes—in biologically male individuals. X and Y sex chromosomes only have certain regions (autosomal regions) that are homologous.
At the molecular level, DNA has a characteristic double-helix shape, and though this wasn’t observed by scientists until mid-20th century, it has quickly become one of the most iconic shapes in all of science.
The sides of this twisted ladder are composed of alternating molecules of sugar (deoxyribose, to be precise) and a phosphate group. Each side is named for the direction it runs in (5’–3’ or 3’–5’). The ladder’s “steps” are composed of two nitrogenous bases, held together with hydrogen bonds.
Four nitrogenous bases—cytosine, thymine, adenine, and guanine—can be found on strands of DNA. In terms of their chemical structure, cytosine and thymine are pyrimidines and adenine and guanine are purines. Adenine and thymine (A and T) always pair together, and guanine and cytosine (G and C) always pair together. They pair this way because A and T form two hydrogen bonds with each other and G and C form three.
At the most basic level, different sections of DNA strands (sequences of nitrogenous bases) provide instructions for the synthesis of protein.
Replication of a cell’s DNA occurs before a cell prepares to undergo division—either mitosis or meiosis I.
It takes place in three(ish) steps.
- DNA unwinds from the histones.
- An enzyme called DNA helicase opens up the helix structure on a segment of DNA, breaking the bonds between the nitrogenous bases. It does this in a zipper-like fashion, leaving a replication fork behind it.
- Here’s where things get funky.
- On the 5’–3’ strand of the DNA, an enzyme called DNA polymerase slides towards the replication fork and uses the sequence of nitrogenous bases on that strand to make a new strand of DNA complementary to it (this means that its bases pair with the ones on the old strand).
- On the 3’–5’ strand, multiple DNA polymerases match up base pairs in partial segments, moving away from the replication fork. Later, DNA ligase connects these partial strands into a new continuous segment of DNA.
Want to know something neat? When a DNA molecule replicates, each of the resulting new DNA molecules contains a strand of the original, so neither is completely “new.” Also, new histones are made at the same time the DNA replicates so that the new strands of DNA can coil around them.