Name the smallest known cell.

Name the largest known cell.

How do lysosomes perform the functions of defence,digestion and cleansing in the cell?

Which plastid would you expect to be present in $(i)$ Papaya and $(ii)$ Grass?

Give short answers:
$(i)$ What is the role of proteins and lipids in the plasma membrane?
$(ii)$ Why is the plasma membrane called selectively permeable?
$(iii)$ What is the role of cellulose in the cell wall?
$(iv)$ What is meant by plasmolysis?
$(v)$ What is the advantage of the flexibility of the cell membrane?
$(vi)$ Name the process which is useful for the movement of substances like $CO_{2}$ and $O_{2}$ across the cell membrane.

Name the single membrane-bound cell organelle which is found in an animal cell.