Biological Effects on Potato

Biological Effects on Potato

Potatoes, like all other vegetables contain the enzyme catalase, which

breaks down the toxic waste product of hydrogen peroxide. Potatoes

have an unusual response to long exposures of light, where the

chemical properties are altered within the cells. This can be seen as

the surface changes green in colour. Storage conditions of potatoes

are therefore important, to ensure potatoes remain in the original

state after cultivation. Within this assessment, the effects of how

light intensity within storage of potatoes effect the rate of catalase

activity will be investigated, and a suitable experiment to obtain

results showing this will be devised.

Potatoes belong to a family of plants called the Solacaneae, which

includes the tomato and eggplant. These species of plants naturally

produce glycoalkaloids, a toxic substance to protect them from

predators. Within potatoes, this glycoalkaloid is solanine, and is

present within relatively high concentrations within the stem and

leaves. However, within the tuber, solanine is low in concentration

and can be found on the surface, about one eighth of an inch in depth.

When exposed to light, the solanine concentration increases by about

ten times. Simultaneously, the chlorophyll is produced, which changes

the surface to green in colour. The formation of chlorophyll has no

effect on the increase of solanine, however, the conditions which

accumulate it, also increases the concentration of the glycoalkaloid.

Thus, a green surface colour on a potato tuber is a clear indication

of increased solanine levels.

Solanine, like all glycoalkaloids are is a toxic substance to a...

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...ks of different intensities. Ensure you repeat

each light intensity potato disk experiment twice to obtain three sets

of results for each one.

Hypothesis

When exposed to light, the solanine concentration on the surface of

the skin will increase. The light will also accumulate the formation

of chlorophyll. The increased solanine, like any other glycoalkaloid

will cause the cells to become alkaline. This will cause the

peroxisomes where the catalase is stored to also become a high pH.

Catalase, whose optimum pH is around 7.6, will slow down the rate at

which it decomposes the hydrogen peroxide due to this change in high

pH.

Those potatoes closer to the fluorescent lamp will experience a higher

light intensity. This will cause more chlorophyll and solanine

formation faster than those potatoes further away.