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Heather Smith
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Biochemistry
WGU
August 24, 2015

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Model of Essential Amino Acid Essential amino acids are those amino acids in which the body can not make on its own, instead they must be procured through the foods that we eat (Helmenstein). Lysine is one of the essential amino acids. Two of the chemical properties of lysine are that it is positively charged and it is hydrophilic, which means water loving so it easily dissolves in water (National Center for Biotechnology Information).

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Each NH2 contains one nitrogen atom and two hydrogen atoms­ represented on the diagram as intertwining pipe cleaners color coded to there respective elements (ie NH2 has blue and neon) Each CH2 contains one carbon atom and two hydrogen atoms (pink and neon) OH contains one oxygen atom and one hydrogen atom (orange and neon)

Diagram of Protein Structure

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Dehydration : Creating a Peptide Bond

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Diagram: Peptide Bond Broken by Hydrolysis

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The Four Forces that Stabilize Proteins at Tertiary Level

The tertiary structure of proteins are dictated by several factors. Non polar molecules are also hydrophobic and they tend to gravitate towards the center of a protein structure, where there contact with water is minimized. In addition the polar (hydrophilic) R groups tend to want to congregate towards the outer aspects of the protein structure. A weak force occurs when there are tightly packed non polar R groups inside the protein, this is called Van der Waals interaction.
Hydrogen bonds are medium strength bonds that occur with hydrophilic or polar amino acid side chains. Salt bridges are strong ionic bonds that occur with the exchange of electrons among the positively and negatively charged particles in the R groups of the polypeptide. The formation of disulfide bridges occurs when there is a strong bond between two cysteine amino acids and is important to the stabilization of protein tertiary structure. (Protein Structure).

Explain how Bovine Spongiform Encephalopathy Occurs at the Molecular Level Bovine Spongiform Encephalopathy also known as BSE or mad cow disease emerged in
Great Britain during the 1980’s. BSE is a prion disease mainly affecting cattle, but can be spread to humans through consuming improperly cooked meat from the cattle infected with the disease
(Tortura, 2007). Prions can also be spread to other cattle from feeding them meal that has been made from or contaminated by other infected animals. Prions are formed by the misfolding of the normal protein structure. The jumbled up protein structure of these prions serve as a template

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to convert other healthy proteins to the disease causing form. The healthy form of protein is called PrPc and the abnormally shaped protein is known as PrPsc. The diseased proteins group together on the outside of neurons causing plaques. The plaques damage or impair the function of the neuron to the point that the cell undergoes cell death or apoptosis. The death of so many neurons can explain the abnormal behavior in animals with advanced disease. Chaperone proteins normally function to help guide newly formed proteins to their properly folded shape. In the case of prion diseases, the abnormally shaped protein PrPsc functions as a chaperone that influences the normal form of the protein PrPc to take on the shape of PrPsc. Due to the abnormal shape of these proteins they are hydrophobic and tend to aggregate together and they form plaques. The plaques of misfolded proteins that have aggregated on the outside of the neurons are believed to cause the cell to undergo apoptosis. Recommendations to Reduce Transmission of BSE There are several recommendations that a country without regulation can impose to help reduce the transmission of BSE. Idealy they could ban giving animals feed that is from or possibly contaminated by sources such as other cattle, sheep or goats. Implement routine testing for BSE of all cattle intended for human consumption. Adopt a process to properly dispose of the bodies of infected animals through alkaline hydrolysis. This process involves “ dissolving carcasses in tissue digesters, vats of lye that are essentially giant pressure cookers heated to

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300 degrees Fahrenheit”(Grady). Since it is still questionable whether other methods used to dispose of the bodies of infected animals are effective.

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Works Cited
BSE Info ­ Prion Definition. (n.d.). Retrieved August 24, 2015, from http://www.bseinfo.org/priondefinition.aspx Bovine Spongiform Encephalopathies (BSE) or Mad Cow Disease: Control Measures. (2015,
February 10). Retrieved August 24, 2015, from http://www.cdc.gov/prions/bse/control­measures.html Grady, D. (2004, January 5). With Diseased Animals, Disposal Isn't Simple. Retrieved August
24, 2015. Helmenstein, A. (n.d.). What Are the Essential Amino Acids? Retrieved August 22, 2015, from http://chemistry.about.com/od/lecturenoteslab1/a/Essential­Amino­Acids.htm National Center for Biotechnology Information. PubChem Compound Database; CID=5962, https://pubchem.ncbi.nlm.nih.gov/compound/5962 (accessed Aug. 22, 2015).
Protein Structure. (2009). Retrieved August 22, 2015, from http://www.particlesciences.com/news/technical­briefs/2009/protein­structure.html Tortora, G., Funke, B., & Case, C. (2007). icrobiology: An introduction
M
(9th ed., pp. 412­414).
San Francisco, CA: Benjamin/Cummings

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