BIOLOGY

Potato Osmolarity Question:​ To what extent will the concentrated solution affect the mass and osmolarity of a

potato?

Background Information:

Cell transport is the process of cells moving into or out of the of the cell across the cell membrane. Cell transport divides into two brought categories, passive cell transport and active cell transport. Passive cell transport is an automatic process, which means energy is not required during the process. An example of passive cell transport would be diffusion. Diffusion is when particles move into or out of the cell from an area of higher concentration to an area of a lower concentration and the cell doesn’t use any energy during this process. Active transport is when cells move from an area of a lower concentration to an area of a higher concentration and it does require energy.

Hypothesis:

If the potato is placed in a concentrated sucrose of 0.8 or 0.6 then it will be hypertonic solution, but if it’s placed in a concentrated sucrose of 0.2 or 0.4 then it will be a hypotonic solution.

Variables:

Independent: - Concentration of sucrose

Controlled: - Amount of sucrose solution (20 ml)

- Potato

· -  Room temperature

· -  Amount of time in solution

Dependent:

- Percent change in mass

Materials:

· -  Beakers/tubes

· -  Concentrated sucrose solution

· -  Potato

· -  Ruler

· -  Scalpel

· -  Cork borer

· -  Paper towel

· -  Balance

Procedure:

1. Label the beakers/tubes of sucrose you will use.

2. Measure and record the sucrose solution volume in column 2 of the table.

3. Cut a piece of the potato using the cork borer and measure it to fit it into your

beaker/tube.

4. Weigh the potato piece using a balance, record your data, and put it in the beakers. Fill

your tube with the sucrose solution and make sure that the solution totally cover the

potato.

5. Leave it for 24 hours.

6. Take out one piece from one of the beakers and dry it on a paper towel (do for all five but

one at a time).

7. Reweigh the potato piece using a balance and record the mass of the potato piece.

8. After you finish all five, calculate the change in mass and then the percentage change in mass of each set of potato pieces.

9. Average the 5 trials from using other groups data and graph it.

Data: Trial 1:

Concentration of sucrose solution Molar (M)	Volume of Sucrose solution	Potato piece initial mass	Potato piece mass after 24 hours	Percentage change in mass
0	20 ml	1.094 g	1.300 g	18.80%
0.2	20 ml	1.026 g	0.977 g	-4.80%
0.4	20 ml	1.074 g	0.828 g	-22.91%
0.6	20 ml	1.086 g	0.703 g	-35%
0.8	20 ml	1.010 g	0.618 g	-39%
1	20 ml	0.951 g	0.778 g	-17.14%

Trial 2:

Concentration of sucrose solution Molar (M)	Volume of Sucrose solution	Potato piece initial mass	Potato piece mass after 24 hours	Percentage change in mass
0	20 ml	1.946 g	2.265 g	16.40%
0.2	20 ml	1.928 g	1.947 g	0.99%
0.4	20 ml	1.894 g	1.526 g	-19.40%
0.6	20 ml	1.822 g	1.193 g	-34%
0.8	20 ml	2.059 g	1.202 g	-42%
1	20 ml	1.971 g	1.142 g	-42.10%

Trial 3:

Concentration of sucrose solution Molar (M)	Volume of Sucrose solution	Potato piece initial mass	Potato piece mass after 24 hours	Percentage change in mass
0	20 ml	1.580 g	1.881 g	19.10%
0.2	20 ml	1.707 g	1.715 g	0.50%
0.4	20 ml	1.552 g	1.220 g	-21.40%
0.6	20 ml	1.695 g	1.182 g	-30%
0.8	20 ml	1.642 g	0.973 g	-41%
1	20 ml	1.617 g	0.911 g	-43.70

Trial 4:

Concentration of sucrose solution Molar (M)	Volume of Sucrose solution Milliliter (mL)	Potato piece initial mass Grams (g)	Potato piece mass after 24 hours Grams (g)	Percentage change in mass Percentage (%)
0	20 ml	1.002 g	1.386 g	38.30%
0.2	20 ml	0.961 g	1.150 g	19.70%
0.4	20 ml	0.596 g	0.490 g	-17.80%
0.6	20 ml	0.596 g	0.427 g	-25%
0.8	20 ml	0.535 g	0.380 g	-29%
1	20 ml	0.585 g	0.402	-31.30%

Trial 5:

Concentration of sucrose solution Molar (M)	Volume of Sucrose solution	Potato piece initial mass	Potato piece mass after 24 hours	Percentage change in mass
0	20 ml	2.772 g	3.214 g	15.94%
0.2	20 ml	2.962 g	2.754 g	2.30%
0.4	20 ml	2.949 g	2.230 g	-24.38%
0.6	20 ml	2.975 g	2.040 g	-31%
0.8	20 ml	2.779 g	1.700 g	-39%
1	20 ml	2.884 g	1.870 g	-35.15%

Graphs and Calculations: Average percent change:

Concentration of sucrose solution Molar (M)	Average percent change in mass (g)
0	21.71%
0.2	3.74%
0.4	-21.18%
0.6	-31%
0.8	-38%
1	-33.88%

Graph:

Analysis: 1. Why is it good idea to remove all the potato skin?

The potato skin would not affect the mass change, but it is thick and removing would actually make the diffusion process faster and much easier.

2. Why do we dry the pieces on a paper towel before weighing them?

We dry the pieces on a paper towel because we weighed the potato before it was dry, but now after it was put into the water it’s heavier so it’s gonna affect the weight of the potato piece.

3. Does your graph show any inconsistencies?

4. Explain in biological terms what is happening to the potato pieces in the different sucrose solutions.

There are two terms, hypertonic and hypotonic. If the potato was put into the sucrose and its mass decreased then it’s hypertonic. But if it was put into the sucrose solution and its mass increased then it’s hypotonic.

5. What do you think is the approximate concentration of the cell sucrose of the potatoes?

I think the concentration of the cell sucrose is 0.3, which us the equilibrium level.

6. You could modify this investigation to find out how quickly osmosis happens. Write down a hypothesis you would be testing and a plan for how to do the experiment Include the variables you would need to control to get reliable results.

If we keep the concentration the same in a higher room temperature osmosis will happen faster, and if we keep it the same in lower room temperature it will be slower

Conclusion:

In conclusion, our hypothesis was proven to be wrong. We said the it will be hypertonic if placed in 0.8 or 0.6 concentrated sucrose, and if placed in a 0.2 or a 0.4 it will be hypotonic. But the results were different, when the potato was in the 0 and the 0.2 solution, its mass increased. On the other hand, when it was in a the solutions of 0.4, 0.6, 0.8, and 1 its mass decreased. This shows that the concentrated solution of 0.2 and 0 are hypertonic, and the rest are all hypotonic.

Evaluation:

Overall the experiment was very successful and worked perfectly. We did not face any problems at all and everything worked out smoothly. Cutting a piece out of the whole potato was and using the cork borer to do it was a bit hard, but we got the hang of it after the second try. Another important thing to mention was drying the potato, it was very important to dry the potato before measuring it mass. The water would probably make a difference in the weight of the potato and would add weight to it so we had to dry it before we measure it or everything would be different. This experiment was fun and interesting, we learned many new things and we will hopefully benefit from it.

Work Cited

Wilkin, Douglas, and Niamh Gray-Wilson. “Cell Transport.” CK, CK-12 Foundation, 17 June 2017, www.ck12.org/biology/cell-transport/lesson/Cell-Transport-Advanced-BIO-ADV/.