Youtube video review 1:
Is DNA the most important as well as the most complicated biological molecule that exists?
…Well that’s something to debate over but there is no denying that DNA is super interesting.
DNA (deoxyribonucleic acid) stores the genetic instructions which program all our cell activities. It is a 6 billion letter code that provides the instructions to the making of everything that you are.
Each cell in the human body has 46 chromosomes each containing a single DNA molecule. DNA is a nucleic acid and so is RNA. They are polymers meaning that they comprise of many small repeating molecular units called nucleotides forming polynucleotides. To make up a nucleotide you need a phosphate group, 5 carbon sugar, and 1 of the 4 nitrogenous bases Adenine, Thymine, Cytosine and Guanine.
For your information, in eukaryotic organisms DNA doesn’t exist as a solitary polynucleotide, but as a pair of molecules wound tightly together, forming a twisting ladder shape, you know what I’m talking about, a double helix. It’s formed by the hydrogen bonding between nitrogenous bases where adenine bonds with thymine via two hydogen bonds and cytosine bonds to guanine via 3 hydrogen bonds forming what is called base pairs.
I bet you didn’t know that chromosome 1 is the largest of all our chromosomes and a single molecule of DNA in it contains 270 million base pairs which if written down equals 200,000 pages long.
Let’s do the MATH:
Each cell= 46 chromosomes = roughly 6 billion base pairs in a cell
Not to mention we are made up of billions if not trillions of cells ourselves. Work that out math fanatics cause I have a headache just thinking about it!!!
Think about it this way; you’ll need MORE THAN 10,000 GAME OF THRONES books to fill our ENTIRE GENOME!!! (If you trust Hank’s math).
Yeah… we love A Song of Ice and Fire here… Epic fantasy for the win!!
Three major differences between DNA and RNA:
- RNA is a single-stranded molecule
- Ribose, the sugar in RNA has one more atom of oxygen than DNA’s deoxyribose.
- RNA does not contain thymine. Its fourth nucleotide is the base uracil, so it bonds with adenine instead.
A shocking twist I did not see coming was the fact they LIED TO US!!! Watson and Crick did not discover DNA as we were told nor did they discover that DNA contained genetic information. Circa 1869, a Swiss biologist by the name of Friedrich Miescher, discovered DNA which he then named nuclein (now known as nucleic acid).
Nearly a century later, Rosalind Franklin, a young biophysicist in London, may have been the first to confirm DNA’s helical structure using x-ray diffraction. Also, she figured out that its sugar phosphate backbone exists on the outside of its structure which she shared with Watson and Crick *gasp*.
Hank’s upbeat delivery and quirky stories make this a good watch for even the least science-loving individuals that walk among us (yes, they do exist). The video contains a lot of relevant information that’s explained really nicely for you to understand. I’d recommend this video to anyone with the appreciation for all things awesome, and I’ll admit, it’s really a great “crash course” on DNA.
Green, Hank. “DNA Structure and Replication: Crash Course Biology #10.” Digital video, 2012. http://www.youtube.com/watch?v=8kK2zwjRV0M (accessed 10 Apr 2014).
Contributors: Chris, Roi (editor)