Biochemistry
Similarity of Glycolysis in Prokaryotes and Eukaryotes
Glycolysis is reported as being a pathway that is practically universal for energy extraction that carbohydrates hold available and this is true for eukaryotes, prokaryotes as well as aerobes and anaerobes. (Essential Biochemistry, 2014, paraphrased) Only eukaryotes have mitochondria. Some prokaryotes are reported to be photosynthetic and to use “an electron transport chain to make ATP.” (Essential Biochemistry, 2014, p. 1)
It is believed that cellular respiration may have undergone evolution through modification processes that are photosynthetic in order to gain their energy from food. (Georgia Tech University, 2014, paraphrased) In Substrate-level phosphorylation, a phosphate is transferred to ADP from a high-energy phosphorylated organic compound. Oxidative phosphorylation is reported to synthesize the largest part of the cell’s ATP and it is stated that this takes place during respiration of cells. The energy for ATP syntheses resulting in ATP from ADP as well as inorganic phosphate is the result of a proton-motive force. (Georgia Tech University, 2014, paraphrased)
Oxidative phosphorylation results due to an emergence of new properties because of an interaction of already existing properties demonstrating how new properties emerge at each level of the biological hierarchy.
References
Glycolytic Enzymes (2014) Essential Biochemistry. Retrieved from: http://www.wiley.com/college/pratt/0471393878/instructor/structure/glycolysis/index.html
The Theme of Unity and Diversity in Glycolysis and Cellular Respiration (2014) Schmoop. Retrieved from: http://www.shmoop.com/cell-respiration/unity-diversity.html
Respiration, chemiosmosis and oxidative phosphorylation (2014) Biology 1510 Biological Principles. Georgia Tech Biology. Retrieved from: http://bio1510.biology.gatech.edu/module-3-molecules-membranes-and-metabolism/05-respiration-chemiosmosis-and-oxidative-phosphorylation-2/
Part II
Caffeine, Sugar and Brain Alertness
When caffeine and sugar reaches a cell in the body, it meets the plasma membrane. The plasma membrane is that which makes the decision of the cell’s reaction to any substance including caffeine. (Macmillian Higher Education, 2014, paraphrased) The caffeine molecule, due to being large and polar is not likely to undergo diffusion through the cell membrane’s nonpolar lipids and instead it reported to bind to “receptors on the surface of the nerve cells in the brain.” (Macmillian Higher Education, 2014, p. 1)
The nucleoside adenosine is reported to accumulate in the individual’s brain when then individual undergoes stress or has ongoing mental activity. (Macmillian Higher Education, 2014, paraphrased) However, when it does binds to a specific receptor in the brain, “adenosine sets in motion a signal transduction pathway that results in reduced brain activity, which usually means drowsiness. This membrane-associated signaling by adenosine has evolved as a protective mechanism against the adverse effects of stress.” (Macmillian Higher Education, 2014, p. 1)
Caffeine is reported to have an adenosine structure that is three dimensional in nature with the ability to bond the receptor of the adenosine however, since this binding fails to activate the receptor, caffeine is allowed to function “as an antagonist of adenosine signaling, with the result that the brain stays active and the person remains alert.” (Macmillian Higher Education, 2014, p. 1) Caffeine additionally blocks the enzyme cAMP phosphodiesterase” which acts in “signal transduction to break down the second messenger cAMP. (Macmillian Higher Education, 2014, paraphrased)
References
Cell Membranes and Signaling (2014) Macmillan Higher Ed. Retrieved from: http://www.macmillanhighered.com/catalog/static/whf/hillispreview/POL_Mktg_CH05_.pdf
