A. Explain the term "concentration gradient". Make sure to discuss the difference between a solution's concentration and a concentration gradient.
B. An artificial cell contains 0.2 M FRUCTOSE and 0.8 M glucose, AND 2M SUCROSE. It is placed into a solution containing 0.5 M fructose, 0.5 M glucose, and 1 M sucrose. The 'cell' membrane is permeable to glucose and fructose, but not sucrose.
1. For which solutes to concentration gradients exist and why?
2. Which solutes will exhibit net diffusion into the cell?
3. Which solutes will exhibit net diffusion out of the cell?
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A. The term "concentration gradient" refers to the gradual change in the concentration of a solute within a particular medium or solution. It exists when there is a difference in the concentration of a solute between two regions. In simpler terms, it is the variation in the concentration of a substance over a distance.
Now, let's discuss the difference between a solution's concentration and a concentration gradient. The concentration of a solution refers to the amount of solute that is dissolved in a given amount of solvent. It is often expressed in terms of molarity, which represents the number of moles of solute per liter of solution.
On the other hand, a concentration gradient specifically refers to the difference in concentration between two regions. It signifies how the concentration of a substance changes as you move from one point to another within a system. It can be described as a slope that exists due to the variations in solute concentration. The concentration gradient provides the driving force for many processes, such as diffusion.
B. Now let's address the questions related to the artificial cell and the surrounding solution.
1. For which solutes do concentration gradients exist and why?
In this case, concentration gradients exist for fructose and glucose since there is a difference in their concentrations between the artificial cell and the surrounding solution. The artificial cell has 0.2 M fructose and 0.8 M glucose, whereas the surrounding solution contains 0.5 M fructose and 0.5 M glucose. Thus, there is a concentration gradient for both fructose and glucose.
On the other hand, there is no concentration gradient for sucrose since its concentration is the same both inside the artificial cell (2 M) and in the surrounding solution (1 M). As sucrose cannot diffuse across the cell membrane, it does not establish a concentration gradient.
2. Which solutes will exhibit net diffusion into the cell?
Since the cell membrane is permeable to both fructose and glucose, they can diffuse across it. In this case, fructose will exhibit net diffusion into the cell. This is because the concentration of fructose is higher in the surrounding solution (0.5 M) compared to inside the cell (0.2 M), creating a concentration gradient that drives fructose into the cell through diffusion.
3. Which solutes will exhibit net diffusion out of the cell?
Unlike fructose, glucose will exhibit net diffusion out of the cell. This is because the concentration of glucose is higher inside the cell (0.8 M) compared to the surrounding solution (0.5 M), creating a concentration gradient that drives glucose out of the cell through diffusion. However, it's important to note that sucrose will not exhibit any net diffusion as it cannot cross the cell membrane due to its impermeability.
In summary, in this scenario, fructose will diffuse into the cell while glucose will diffuse out of the cell, driven by their respective concentration gradients. Sucrose, on the other hand, will not exhibit any net diffusion due to its inability to cross the cell membrane.