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Water Regulation
Rubric
Contributed by: New York State Alternative Assessment in Science Project (NYSED)

Maximum Score - 24 Points

1. Observations 9 points total

    • Allow 1 point for each of the following components:

Correct rate of contraction
Indication of no change over time
Answer is correct and in complete sentences

1A. Pond Water 3 points total

Sample of acceptable answer for 1A

The contractile vacuole pumped twice per 30 second interval the whole time.
1B. Solution A 3 points total

Sample of acceptable answer for 1B

The contractile vacuole initially pumped 2 times per 30 second interval. This rate increased to 4 times per 30 second interval and then remained constant.
1C. Solution B 3 points total

Sample of acceptable answer for 1C

The contractile vacuole initially pumped 2 times per 30 second interval. This rate decreased to 1 time per 30 second interval and then remained constant.
2. Relationship Between Water Concentration 2 points total

    • Allow 1 point for part A and 1 point for part B.

2A. The concentration of material in solution A was less than pond water.

2B. The concentration of material in solution A was greater than pond water.
3. What Would You Add to Solution A? 1 point total

    • Allow 1 point if the student states that a solute, such as salt, could be added to solution A to restore the vacuole concentration to the same rate as in the pond water.
4. Explanation of Answer to Question #3 3 points total

    • Allow 1 point for each of the following:

States or implies correct relationship between water and amount of solute.

States or implies correct relationship between concentration of solute and activity of contractile vacuole.

Answer is correct and in complete sentences.

Sample of acceptable answer:

I would add solute to the solution in order to increase the concentration of solute. This would decrease the concentration of water and the paramecium wouldn’t have to pump as often.
5. What Would You Add to Solution B? 1 point total

    • Allow 1 point if the student states that a solvent, such as water, could be added to solution B.
6. Explanation of Answer to Question #5 3 points total

    • Allow 1 point for each of the following:

States or implies correct relationship between concentration of water and amount of solute in a solution.

States or implies the correct relationship between concentration and the activity of the contractile vacuole.

Answer is correct and in complete sentences.
7. Prediction if the Contractile Vacuole Failed 1 point total

    • Allow 1 point if the student states or implies that the paramecium becomes non-functional (i.e. dies or bursts).
8. Explanation of Answer to Question #7 2 points total

    • Allow 1 point if the student includes the following components:

States or implies the correct relationship between function of the vacuole and the well being of the paramecium or states or implies the correct relationship between too much water and the death of the organism.

Answer is correct and in complete sentences.
9. Two Biological Processes 2 points total

    • Allow 1 point for each of the biological processes named:

Osmosis
Homeostasis
Other processes may be appropriate

Highest possible score - 24 points


 

 

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