Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.

Prokaryotic Cell	Eukaryotic Cell
$1.$ Size: generally small $(1-10 \,\mu m)$ $1 \,\mu m = 10^{-6} \,m$	$1.$ Size: generally large $(5-100 \,\mu m)$
$2.$ Nuclear region: ................... and ...............	$2.$ Nuclear region: well defined and surrounded by a nuclear membrane
$3.$ Chromosome: single	$3.$ More than one chromosome
$4.$ Membrane-bound cell organelles absent	$4.$ .........................

Who discovered cells,and how?

Carry out the following osmosis experiment:
Take four peeled potato halves and scoop each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,
$(a)$ Keep cup $A$ empty.
$(b)$ Put one teaspoon sugar in cup $B$.
$(c)$ Put one teaspoon salt in cup $C$.
$(d)$ Put one teaspoon sugar in the boiled potato cup $D$.
Keep these for two hours. Then observe the four potato cups and answer the following:
$(i)$ Explain why water gathers in the hollowed portion of $B$ and $C$.
$(ii)$ Why is potato $A$ necessary for this experiment?
$(iii)$ Explain why water does not gather in the hollowed out portions of $A$ and $D$.

Make a comparison and write down ways in which plant cells are different from animal cells.

Why is the plasma membrane called a selectively permeable membrane?

If the organization of a cell is destroyed due to some physical or chemical influence,what will happen?