Selective Membrane’s Selectivity

Take a deep breath. And exhale. You may not realize it, but millions of cells in your body just recognized the presence of oxygen and controlled the absorption and internal distribution of O2. One such example of the distribution is to the mitochondria, which requires oxygen for cellular respiration. While we understand that the phospholipid bilayer of the plasma membrane is fluid and chooses which substances pass, how does the cell “decide” when to let O2 enter and why?

When I was scrolling through Twitter the other day, I came across an article that caught my eye. The winners of the Nobel Prize in Physiology or Medicine had been announced. I clicked on the article and nearly jumped out of my chair. My questions had been answered! Three distinguished researchers: William G. Kaelin Jr. of Harvard University, and Gregg L. Semenza of Johns Hopkins University, and Peter J. Ratcliffe’s of the Francis Crick Institute in Britain and Oxford University were awarded the Nobel Prize for their discovery on how cells react and adapt to fluctuating oxygen levels.

As we know, oxygen is crucial for cell function. Cellular respiration in the mitochondria requires oxygen in order to produce the cell’s usable energy, ATP. In the current unit, we are beginning to understand exactly how a cell uses oxygen and glucose to produce ATP. Cellular respiration requires six oxygen molecules. It is simple to understand the exact ratio of molecules, but it is much more difficult to grasp how a cell regulates oxygen concentration. In the article published by the Los Angeles Times, the research analyzes how cells adapt and alter in response to oxygen variability. In unit two, we studied cells and selectively permeable membrane.

Kaelin Jr’s, Semenza’s, and Ratcliffe’s discovery develops new understanding of cell function in response to oxygen. Semenza studied a hormone and a protein segment in genes: EPO and HIF respectively. EPO is the hormone erythropoietin which controls production of red blood cells. HIF is a protein that responds to oxygen levels. The three scientists discovered that the concentration of both of these is proportionally related to the oxygen concentration. When there is a low amount of HIF, oxygen levels are high. When there is a high amount of HIF, oxygen levels are low. While the terminology can be complicated, the ideas is really very simple. Proteins and genes in cells regulate the cell in response to oxygen. They found that these abilities were not just limited to kidney cells. Cells throughout the body, especially specialized cells have the ability to adapt in response to oxygen variability or accessibility.

We can use this new knowledge in class to better understand two main concepts: why gases such as oxygen diffuses quicker through the membrane and also how cells allow oxygen diffusion. This breakthrough research helps us understand how very complicated cells are. Even when we feel we have a surface level understanding, asking questions can unearth amazing discoveries like this one. The historic research of these three men earned them the honor of the Nobel Prize as well as $918,000 to continue their research. I am sure the news of the award let them breathe easy.

About Mr. Mohn

Biology Teacher

This entry was written by Veronica S. and tagged . Bookmark the permalink.

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