The diagram illustrates the movement of molecules across an artificial membrane in a U-shaped glass tube. A 1% starch solution was poured into the left side of the tube, and distilled water was placed in the right side of the tube.
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Question 1
1.
If a 1% salt solution were substituted for the starch solution in this setup, the results would be
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Question 2
2.
Explain why the liquid level on the left side changed over the 20-minute period.
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Question 3
3.
A cube cut from a potato is placed in a beaker of distilled water. The potato cells have a relatively high concentration of starch and a relatively low concentration of water. The diagram represents the water and starch molecules in and around one of the potato cells in contact with the water in the beaker.
Which row in the chart correctly describes what would be expected to occur in the potato cells, with regard to both the starch and water molecules?
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Question 4
4.
Two skin cells from the same animal were each placed in a different solution. The diagrams below represent the changes that occurred in each cell after 5 minutes in each solution.
Which cell was placed in a solution containing a higher concentration of salt than the concentration of salt normally found in these skin cells? Support your answer.
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Question 5
5.
Three potato slices with the same mass were each placed in three beakers, each labeled with its number and contents. After 30 minutes, the potato slices were removed from the solutions, dried with a paper towel, and the mass was determined. The results are shown in the table below.
Identify a process that caused these changes in mass of each of the three slices.
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Question 6
6.
A student placed artificial cells, each containing a 25% sugar solution, into three different beakers containing sugar solution which varied in concentration from 0% to 25%. The setups are shown below.
The student collected data on the mass of each artificial cell. The student predicted that the cell in the beaker with 25% sugar solution would have the greatest change in mass after 24 hours. Would his prediction be correct? Support your answer.
A student prepared two potato cubes by cutting 2 cm x 2 cm sections from the same potato. Next, she determined the mass of each of the cubes and recorded the information in her lab notebook.
She then placed one cube in a beaker of distilled water and the other in a beaker with an equal volume of concentrated salt solution. After 20 minutes, she removed both of them from the beakers and again determined the mass of each cube.
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Question 7
7.
Which statement correctly describes the effect on the mass of one of the cubes after the 20-minute period?
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Question 8
8.
The student placed a thin slice of potato in a drop of water on a glass slide. She added a coverslip and a drop of indicator. Using a compound light microscope, she examined the slide of potato and made the drawing below.
The blue-black-stained structures labeled in her drawing are most likely
A student prepared a wet-mount slide of red onion skin and observed it under high power of a compound light microscope (view A). After adding a substance to the slide and waiting one minute, the student observed that there were changes in the cells (view B).
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Question 9
9.
Identify the specific substance that diffused to cause the change in appearance from view A to view B.
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Question 10
10.
Identify one substance that could have been added to the cells on the slide in view A that would make them resemble the cells observed in view B.
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Question 11
11.
BONUS: In the box above, sketch how view B would appear when viewed under lower power of the same compound light microscope.