AP BIOLOGY

Detailed explanation-1: -Arachidonic acid and docosahexaenoic acid are key fatty acids; a minimal increase in the percentage of arachidonic acid in phospholipids tails improves membrane flexibility due to its four double bonds.

Detailed explanation-2: -The plasma membrane is flexible and is made up of organic molecules called lipids and proteins. The flexibility of cell membrane enables the cell to engulf in food and other material from its external environment. Such process is known as endocytosis. It is observed in Amoeba.

Detailed explanation-3: -The cytoskeleton provides a structural framework for the cell, serving as a scaffold that determines cell shape and the general organization of the cytoplasm. In addition to playing this structural role, the cytoskeleton is responsible for cell movements.

Detailed explanation-4: -The chemical structure of the cell membrane makes it remarkably flexible, the ideal boundary for rapidly growing and dividing cells. Yet the membrane is also a formidable barrier, allowing some dissolved substances, or solutes, to pass while blocking others.