Question

1. How does osmosis helps in food preservation?

2. Plants mostly have dead cells on their body surface. On the other hand, most animals have living cells on their surface. Why?

Answer 1

1) Food is preserved by adding salts and sugars to them. These chemicals remove the water out of microbial cells causing them to shrink.which is the mechanism of osmosis . Jams, jellies, fruit syrups, honey etc, are preserved by high sugar concentration.,which again shows osmosis.

2).Most plant tissues are dead, since dead cells can provide mechanical strength as easily as live ones, and need less maintenance. These dead cells are limited to certain regions that are responsible for providing mechanical strength or other protective functions. Since growth in plants is limited to certain regions within the plant body, these dead cells do not interfere with the growth of the plants. But in animals the growth pattern is not similar to that of plants for which dead cells, if present, would interfere with the growth of the animal. Moreover, an animal needs to be constantly moving, hence, cells too have to be very active so as to provide the energy and necessary support to carry out such activities.

Hope this helps :)