Question

high demand questions questionsheet 13 cubes of potato were placed in beakers of soil. the beakers were sealed and kept in different conditions. the mass of the potatoes was measured at the start, after 3 days, 5 days and 7 days. the table shows the results. (a) in which conditions did the potato lose most mass after 5 days? 1 (b) in which condition did the potato lose least mass after 7 days? 1 (c) in which conditions did the potato lose approximately 20% of its mass after 7 days? 1 (d) calculate the percentage loss of the potato, when kept in damp conditions at $20^{circ}c$ after 3 days. answer ... 2 (e)(i) name the process which is responsible for the loss in mass of the potato. 1 (ii) name two types of organism which carry out this process. 1. ... 1 2. ... 1

Explanation:

Step1: Calculate mass loss for each condition after 5 days

For Damp \(20^{\circ}C\): \(50 - 19.8=30.2\) g.
For Dry \(20^{\circ}C\): \(50 - 44.2 = 5.8\) g.
For Damp \(5^{\circ}C\): \(50 - 46.7=3.3\) g.
For Dry \(5^{\circ}C\): \(50 - 49.1 = 0.9\) g.
For Damp \(45^{\circ}C\): \(50 - 49.0=1.0\) g.
For Dry \(45^{\circ}C\): \(50 - 49.4 = 0.6\) g.

Step2: Calculate mass loss for each condition after 7 days

For Damp \(20^{\circ}C\): \(50 - 8.6 = 41.4\) g.
For Dry \(20^{\circ}C\): \(50 - 40.3=9.7\) g.
For Damp \(5^{\circ}C\): \(50 - 44.3 = 5.7\) g.
For Dry \(5^{\circ}C\): \(50 - 48.5=1.5\) g.
For Damp \(45^{\circ}C\): \(50 - 48.8 = 1.2\) g.
For Dry \(45^{\circ}C\): \(50 - 49.1=0.9\) g.

Step3: Calculate 20% of initial mass (\(m = 50\) g)

\(20\%\text{ of }50=\frac{20}{100}\times50 = 10\) g.
Find the condition where mass loss is approximately \(10\) g.
For Dry \(20^{\circ}C\): mass loss after 7 days is \(9.7\) g \(\approx10\) g.

Step4: Calculate percentage loss for Damp \(20^{\circ}C\) after 3 days

Mass loss \(=50 - 32.4=17.6\) g.
Percentage loss \(=\frac{17.6}{50}\times100\%\).

Step5: Recall the process

The process responsible for mass loss of potato (decomposition) is decomposition (or respiration if considering microbial action on potato cells, but more accurately decomposition as it involves external organisms).
Organisms that carry out decomposition are bacteria and fungi (or saprophytic bacteria and saprophytic fungi).

Answer:

(a) Damp \(20^{\circ}C\)
(b) Dry \(45^{\circ}C\)
(c) Dry \(20^{\circ}C\)
(d) \(\frac{17.6}{50}\times100\% = 35.2\%\)
(e)(i) Decomposition (or Respiration in a broader biological sense, but decomposition is more context - appropriate here)
(ii) 1. Bacteria 2. Fungi