A Study on Molecular Biology: Investigating DNA and Diverse Protein Types

Molecular Biology is the study of cellular biology on a molecular level which is where DNA molecules are, which is what give people their heredity. DNA, or Deoxyribonucleic acid, has two strands that is called the double helix. Each strand is a sugar phosphate back bone. (Simon, 2013, p. 174) Connecting these strands are four nitrogenous molecules known as Adenine, Thymine, Guanine, Cytosine. These molecules are known as nucleotides. Adenine always connects with Thymine and called a base pair. Likewise, Guanine always attaches with Cytosine, and they are a base pair.

This base-pairing acts like a code when DNA is ready to duplicate its self. When DNA duplicates itself, the two strands of the double helix unwind and the base pairs split apart, new DNA nucleotides connect with its base pair of the unwound DNA. DNA nucleotides are chemical units that consist of a phosphate connected to a deoxyribose sugar that is connected to one of the four nitrogenous molecules known as Adenine, Thymine, Guanine, Cytosine. If we abbreviate these we get ATGC. Using abbreviates for these molecules you can write DNA sequencing code. If a polynucleotide has the sequence ATGC, then the complementary polynucleotide must be TACG in order to connect to form new DNA. T-A, A-T, C-G, G-C is always how the base pairs come together. This is called the base paring rule. The process of adding nucleotides to their base pair is very rapid, about 50 nucleotides per second with a an accuracy rate of less than one per one billion incorrectly paired. Wow that is fast. If you could type 50 characters per second, that’s about 10 words per second, which is about 600 words per minute (wpm). With less than one typo per billion, that is astonishingly fast. Just image typing sequencing code such as ATGC at 600 wpm, That is what is going on inside the nucleus of a cell where the DNA is.

RNA, or ribonucleic acid, is the single strand version of DNA. RNA and DNA have the same chemical structure with two expectations. In RNA, thymine losses its H3C atoms and becomes what is known as a Uracil Molecule. RNA also contains a ribose sugar instead of a deoxyribose sugar which DNA has.

“A typical gene consists of thousands of nucleotides in a specific sequence.” (Simon, 2013, p. 179) The sum these nucleotide sequences in an organisms DNA is called its genotype. This may be just a coincidence, but I think the term genotype is the perfect name because it refers to the type of genes in DNA, but it could also reference the typing of the sequencing code such as ATGC. An organism’s physical traits such as brown hair, is a phenotype. (Simon, 2013, p. 178).

DNA writes the code for the synthesis of proteins, and proteins determine the phenotype. DNA does not directly build proteins though, rather it creates and sends the coded information in the form of RNA to the ribosome, and the ribosome builds the protein. So if specific inherited traits are not directly found in the DNA itself, otherwise known as the genotype of an organism, then in can be found in the organisms phenotypes which are created by the process of protein synthesis which needs the RNA that DNA creates. Therefore all the parts of a living cell are created and defined based on the proteins that are created, based on the DNA nucleotide sequences. Because of this, DNA through the process of protein synthesis is responsible for the ultimate expression of the characteristics in the organism.

The chain of events that lead from DNA to cell type to a living organism is very important. The chain starts with the DNA and flows downstream from there. Any disruption in the chain can result with in an different outcome later downstream. Therefore interference in protein synthesis can result in disruption of the cell function which effects bodily processes. Disruptions in protein synthesis could create all kind so medical problems even death if the cells of vital organs are not functioning properly because they do not have the correct proteins they need to live.

Taking a closer look at the process of DNA creating protein synthesis, at first the DNA has regions that are not coded called intron. The coded areas are called exons. There is a transcription of the DNA that turns it into RNA with a cap and tail on either end. The non-coded introns are removed and the coded exons are spliced together, this is called RNA splicing, creating a complete coding sequence called messenger RNA, or mRNA. The mRNA exits the nucleus and heads to the ribosome. The “flow of information from gene to protein is based on a triplet code.” (Simon, 2013, p. 179) This triplet code is in codons, which is on mRNA. There is also transfer RNA, or tRNA. This tRNA has the opposite form of codon called anticodons. In the ribosome the codon on the mRNA match up with the anticodons on the tRNA. This allows the ribosome to create polypeptides which are amino acids chains which make up a protein.

There are many diverse types of proteins, each determined by the amino acids present. When you eat foods with protein in it, digestive enzymes break down the particles. The pancreas and intestines secrete enzyme’s that break down food particles all the way down to individual protein molecules, then into amino acids. The amino acids are absorbed through the intestinal wall into the bloodstream, once in the bloodstream they can get to anywhere in the body to assist in cell repair. (Angela Brady, 2011, para 4)

According to Angela Brady:

Amino acids are vital to every cell in your body. As cells become damaged or die, amino acids rush in and make repairs or build new cells. Muscle repair is a perfect example -- when you stress a muscle, it causes tiny tears in the muscle fiber. Amino acids come in to repair the damaged cells, then build some new ones as a kind of insurance against future damage. (Angela Brady, 2011, para 5)

Therefore it is important that people eat foods that give them a fair mix of different proteins. Fish, chicken and soy are good examples of foods with health proteins.