Read the following document attached. Biological structures exist at all levels
ID: 219643 • Letter: R
Question
Read the following document attached.Biological structures exist at all levels of organization, from molecules to ecosystems. A structure's physical and chemical characteristics influence its interactions with other structures, and therefore its function. In protein trafficking, structure and function relationships allow proteins to be transported or localized to the appropriate location within and outside a cell. We are going to further investigate the relationship between the physical and chemical characteristics of molecules and where they localize within a cell. Specifically, we are going to look at the results of a few experiments that were designed to understand the role of ionic interactions in localizing molecules to either the cell membrane OR to endomembranes (membranes of organelles like the nucleus, ER, Golgi). Experiments Scientists have designed a molecule, Lact-C2, which binds to negatively charged phospholipids. This molecule emits red fluorescent light as can be seen in Figure 1A. In Figure 1A you should see a cell that has Lact-C2 bound to negatively charged phospholipids in the cell membrane AND in the membranes of some organelles. Lact-C2B K-Ras/Lact-C2 C K-Ras/Lact-C2 K-Ras-3E/Lact-C2 Red Green Yellow Figure 1. Red fluorescence indicates Lact-C2, and green fluorescence indicates K-Ras. Figure panels show localization of (a) Lact-C2, a biosensor showing the presence of negatively charged phospbolids in both plasma membrane and endomembranes in normal cukaryotie cells, (b) K-Ras and Lact-C2 in nomal eukaryotic cells, ()R and Lact-C2 with increased concentrations of eytosolic Ca2 and (d) K-Ras-3E, a mutant form of K-Ras, and Lact-C2 in mal eukaryotic cells. K-Ras is a protein that is positively charged. K-Ras has been modified for these experiments to emit green fluorescent light. In Figure 1B, you can see a normal cell with both K-Ras and Lact-C2. When the two molecules localize to the same spot in the cell, the two colors of light "mix" and look yellow In Figure IC, scientists have conducted an experiment where they added Ca2+ ions to the cell along with K-Ras and Lact-C2. In Figure ID, the results of a different experiment are shown. In this experiment, K-Ras-3E, a form of K-Ras that has fewer positive charges, was modified to emit reen fluorescent light. In Figure ID, you can see a cell under normal conditions with both K-Ras-3E and Lact-C2
Explanation / Answer
This biological experiments are conducted inorder to explain the transport mechanism between and inside the cells.
In this experiments, scients have done 4 types, first they prepared a molecule called Lact-C2, which emits red fluroscent light when binds with the negatively charged phospholipids.
Then they have done the experiment with these Lact-C2 with a cell, which emitts the red when reacted with the negatively charged phospholipids and they are proved with the fig 1.
Same as they designed a molecule called K-Ras and that emitts green fluroscent when reacted with the positively charged phospholipids. in the experiment 2, they added K-Ras to the cell as shown in the fig 2 which emmits the green fluriscent light and inturns when there is also the red colour, it looks like yellow.
In the experiment 3 they added ca2+ to the cell containing both the Lact-C2 and K-Ras, as they are given as fig 3. Where as in the experiment 4 a new molecule called K-Ras-3E has been added to the cell, where it contais a small positive charegs to emit the green light, as it loos like in the fig 4, when the K-Ras-3E and Lact-C2 in the same cell.
From this experiments, scientists are proving that the transport mechanism of the molecule and the physical and chemical characteristics of the molecule and their binding sites in the cell by making them fluroscent and it will become a easy way to identify and characterize them. Also it make clear that the transport of the molecules that will also occurs both inside and outside as well as between the cells.
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