Differentiate between the following pairs on the basis of what is indicated in the brackets:
Leaf and Liver (form in which glucose is stored)
Topic: Storage of glucose in leaf and liver
Answer
In the LEAF, glucose is stored as STARCH. In the LIVER, glucose is stored as GLYCOGEN.
The brackets restrict the answer to the FORM OF STORAGE, so keep to that.
WHY GLUCOSE IS NOT STORED AS GLUCOSE, which is the real biology here: glucose is SOLUBLE and osmotically active, so storing large amounts of it would draw water into the cell and upset its water balance. Starch and glycogen are INSOLUBLE and compact, so they can be stored in quantity without disturbing osmosis.
Both are POLYMERS of glucose — many glucose units joined together by POLYMERISATION. Glycogen is sometimes called "animal starch" for that reason.
Note that what TRAVELS in the phloem is neither: food is transported as SUCROSE, because that is soluble.
| Point of difference | Leaf | Liver |
|---|---|---|
| Storage form of glucose | Starch | Glycogen |
| Found in | Plants | Animals |