Solved: An experiment was carried out on osmosis in carrot (Daucus carota) root tissue... [IB Biology]

An experiment was carried out on osmosis in carrot (Daucus carota) root tissue and potato (Solanum tuberosum) tuber tissue. Similar sized pieces of tissue were cut and soaked in different sucrose solutions for 24 hours. The results are shown in the graph below.

Question

SLPaper 3

Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

[2]

Verified

Solution

potato: $0.26 \mathrm{~mol} \mathrm{dm}^{-3} \checkmark$ carrot: $0.50 \mathrm{~mol} \mathrm{dm}^{-3} \checkmark$

Allow a range of $0.22-0.32$ Allow a range of $0.45-0.55$ (Allow 1 max if no units or either unit is omitted)

Suggest a reason for the difference in the isotonic points for the potato and the carrot tissues.

[1]

Verified

Solution

different dissolved solutes/sugars/sucrose/salts/molarities $\checkmark$ OR may have been grown in different soils giving their tissues different contents $\checkmark$ OR may have been stored under different conditions $\checkmark$ OR may be more dehydrated / different water content $\checkmark$ OR different types of tissue / different age $\checkmark$

Do not accept starch.

From the evidence provided by the graph, evaluate the reliability of these data.

[2]

Verified

Solution

a. the data show clear trends OR a trend line could be drawn through these data OR there are no outliers $\checkmark$

b. the error bars/standard deviations shown OR the error bars/standard deviations vary with concentration $\checkmark$

c. sample size is unknown $\checkmark$

Explain one reason for calculating the percentage change in mass.

[2]

Verified

Solution

a. the change in mass indicates whether the tissue has gained/lost water $\checkmark$

b. the pieces of tissue will not be the same mass «at the beginning of the experiment» $\checkmark$

c. to compare the relative changes in mass $\checkmark$

Question

SLPaper 3

Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

[2]

Verified

Solution

potato: $0.26 \mathrm{~mol} \mathrm{dm}^{-3} \checkmark$ carrot: $0.50 \mathrm{~mol} \mathrm{dm}^{-3} \checkmark$

Allow a range of $0.22-0.32$ Allow a range of $0.45-0.55$ (Allow 1 max if no units or either unit is omitted)

Suggest a reason for the difference in the isotonic points for the potato and the carrot tissues.

[1]

Verified

Solution

Do not accept starch.

From the evidence provided by the graph, evaluate the reliability of these data.

[2]

Verified

Solution

a. the data show clear trends OR a trend line could be drawn through these data OR there are no outliers $\checkmark$

b. the error bars/standard deviations shown OR the error bars/standard deviations vary with concentration $\checkmark$

c. sample size is unknown $\checkmark$

Explain one reason for calculating the percentage change in mass.

[2]

Verified

Solution

a. the change in mass indicates whether the tissue has gained/lost water $\checkmark$

b. the pieces of tissue will not be the same mass «at the beginning of the experiment» $\checkmark$

c. to compare the relative changes in mass $\checkmark$

An experiment was carried out on osmosis in carrot (Daucus carota) root tissue and potato (Solanum tuberosum) tuber tissue. Similar sized pieces of tissue were cut and soaked in different sucrose solutions for 24 hours. The results are shown in the graph below.

Related topics

An experiment was carried out on osmosis in carrot (Daucus carota) root tissue and potato (Solanum tuberosum) tuber tissue. Similar sized pieces of tissue were cut and soaked in different sucrose solutions for 24 hours. The results are shown in the graph below.

Related topics