bio studying

A common laboratory investigation involves putting a solution of starch and glucose into dialysis bag and suspending the bag in a beaker of water, as shown in the figure below. The investigation is aimed at understanding how molecular size affects movement through a membrane. Which of the following best represents the amount of starch, water, and glucose in the dialysis bag over the course of the investigation?

The graph that best answers the question is answer A, since some of the water would go from the solution, and into the bag, and some of the glucose goes out of the bag and into the solution. This would mean that in the bag the water levels would go up, the glucose levels would go down, and the starch levels would stay the same.

Based on Table 1, which of the following percentages is closest to the solute concentration of the grape? a. 0.0% b. 1.3% c. 5.5% d. 10.1%

The answer is answer C. 5.5%. This is because there is a big negative change in the mass of the grape soda (13%) solution and a little positive change in the mass of the grape juice (2.1%) solution, which means that the grape's concentration should be between these 2 percentages and closer to 2.1% than 13%. The answer wouldn't be answer A.(0.0%) because that percentage doesn't match the requirements.

Mercurial sulfhydryl is an inhibitor of aquaporins. Which of the following is the most likely effect of adding Mercurial sulfhydryl to the distilled water solution?

The answer is answer D.(The grape cells will gain water more slowly because of a lack of facilitated diffusion) because while some amounts of water pass though the membrane by simple diffusion, aquaporins let greater water amounts more over a quicker amount of time. The answer wouldn't be Answer B.(The grape cells will gain more water because of the activation of the transport protein) because without facilitated diffusion the grape cells wouldn't gain water quickly.

Which line or lines in the graph represent(s) bags that contain a solution that is hypertonic at 50 minutes?

The answer isn't answer A.(A+B), because at 50 minutes A isn't gaining mass, but B is still gaining mass, and since the bags need to contain a hypertonic solution to be the answer the bags must be gaining mass at 50 minutes, so the answer must be B(B).

Based on Table 1, which of the following best explains the difference in water potential between certain solutions and the grapes?

The answer would be B. (Grape soda and NaCl have a lower water potential because these two solutions caused the grape to lose water) because on the table those two on the graph show the most negative percent change. It would not be answer A. (NaCl and tap water have a lower water potential because those two solutions caused the grape to gain water) because tap water doesn't have a negative percent change, compared to grape soda.

A spherical bacterial cell has a radius of 3um. The human egg cell has a radius of 100um. Which statement correctly indicates the cell that is able to move efficiently exchange materials with the external environment and provides a correct explanation?

The answer would be D.(The bacterial cell, because it has the largest surface-to-volume ratio) since the bacteria cell's surface area-to-volume ratio would be 1:1, and the human egg cell's surface area-to-volume ratio would be 1:3, and in fraction from 1/1 is much bigger than 1/3, since 1/1 is a whole number. Answer B. is wrong because 1/3 is much less than 1/1.

Which line in the graph represents the bag with the highest initial concentration of sucrose?

The answer would be answer A.(A) because that one starts out gaining the most mass, and since solutes go from hypotonic (least sucrose concentration) to hypertonic (most sucrose concentration). This means that A would have the highest initial concentration. It wouldn't be answer D.(D) because that starts out loosing mass, meaning that it would have a lower initial sucrose concentration

Assuming a negligible pressure potential, which of the following best predicts the net movement of the small diffusible solutes and water in the second experiment (Table 2) ?

The answer would be answer A.(small diffusible solutes will diffuse into the grape cells, followed by water.) since small diffusible solutes diffuse into the cell since there is a low concentration in the grape. Also due to the concentration of non diffusible solutes, the grape's interior will now be hypertonic to the grape's exterior, meaning that the water will go to the grape's interior

A student hypothesizes that the solute concentration of grape juice is higher than the solute concentration of the actual grape because the grape juice has added sugar. Based on the data in Table 1, which of the following best evaluates the student's hypothesis?

The answer would be answer D.(The hypothesis is not supported because of the mass of the grape increased in the grape juice). This is because the grape's mass increased in the grape juice solution, which means that the water goes to the grape, making the grape hypertonic to the hypotonic grape juice. If there was added sugar, the grape juice would likely be hypertonic to the hypotonic grape. The answer isn't answer A. since the grape's mass doesn't decrease in this solution.

Which of the following best describes the condition expected after 24 hours?

The correct answer is answer A.(The bag will contain more water than it did in the original condition) because the bag is hypertonic to the hypotonic distilled water. Answer E.(A glucose test on the solution in the bag will be negative) would be wrong since there would still be glucose in the bag.

Simple cuboidal epithelial cells line the ducts of certain human exocrine glands. Various materials are transported into or out of the cells by diffusion. (The formula for the surface area of a cube is 6 X S^2, and the formula for the volume of a cube is S^3, where S=the length of a side of the cube.) Which of the following cube-shaped cells would be most efficient in removing waste by diffusion? A. 10 um size B. 20 um size C. 30 um size D. 40 um size

The correct answer would be answer A.(The cube with 10 um) since the surface-area-to-volume ratio of that cube would be 0.6:1 which is greater than all of the others, including the wrong answer D.(40 um)