Why do plants store carbohydrates as starch rather than sugar?

Answer 1

The most important reason plants store the sugar as starch rather than glucose is because starch is insoluble in water, meaning it won't dissolve spread out in the water that makes up a large portion of the plant's structure. Glucose is soluble, meaning it will. A more efficient than required reason is that glucose is compressed into tighter spaces when stored as starch, saving space.

Answer 2

Plants store most of their energy as carbohydrates while animals and humand store most of their energy as fats. Despite this differnece, the primary cell energy cycle for both, the citric acid cycle, is most readily driven by glucose.

Starch is of course a general name for polymers of glucose, primarily with 1-6 bonds but also 1-3 branches. Single starch molecules can contain several thousand glucose units.

Storing plant energy, in seeds or from season to season as simple sugars has some difficulties. Sugar is quite soluble in water so it tends to diffuse and be lost from the plant. Also many simple organisms, bacteria and fungi, also insects, can readily consume simple sugars so this means plant sugar stores are readily attacked by other organisms.

Starch by contrast is nearly insoluble in water, and only more advanced organisms can create the amylase enzymes necessary to convert starches to sugars.

The breakdown of starch into sugars is energetically favored, however starch is quite stable at any reasonable environmental temperature.

Water insoluble(almost), stable, readily degraded & accessed via enzymes, but not easily accessed by simple organisms. It's a fine energy store for plants.
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Fats(triglycerides) have an advantage in terms of energy per unit mass (9Cal/gm for fat vs 4Cal/gm for carbs), but they require a considerable and complex mechanism (beta-oxidation) to convert fat to energy. Some plants do store considerable energy as (mostly) unsaturates fats (oils).

Answer 3

Since glucose is soluble in water it is harder to store because it increases the concentration of the cells upsetting the osmotic pressure of the cytoplasm. but starch is an insoluble molecule therefore it can be stored in the cells.

Answer 4

So the plant has a store of energy when it can't gather enough glucose to support itself. Starch is insoluble so it can be stored within the plant easily and it can be converted back into glucose quite quickly using enzymes.

Answer 5

Starch is actually made up of many glucose molecules linked together to form long chains. Also the three-dimensional shape that starch takes is much more compact then just storing a bunch of glucose molecules jumbled together. Consider this analogy:

Say you went hunting and you shot ten pheasants. Now you had to bring them home for the autumn feast. Would you rather carry each pheasant separately (imagine trying to juggle ten pheasants) or would you rather tie them together into a long strand? Like in the cell, tying them into a strand would make them much easier to carry and store.

Answer 6

Starch has little affect on the osmotic balence of the cell.

Answer 7

Because glucose is easy to dissolve and starch cannot break down or dissolve

Answer 8

Starch is not reactive, compact, insoluble, and easier to store.

Answer 9

Starch is a polymer made by plants to store energy.

well , plants need energy to grow.

this energy they use is from the sun tomake glucose..well cheaa basically

Answer 10

Less organisms would want to feed on the plant and steal the sugars