Question

in the figure below, what is #1 pointing to? 1 2 3 4 5 integral proteins lipid bilayer phospholipid head

Explanation:

The lipid bilayer is a fundamental structure of cell membranes, composed of two layers of phospholipids. In the image, the structure pointed to by 1 has the characteristic appearance of a lipid - bilayer, with the yellow - colored phospholipid tails and the white - colored phospholipid heads arranged in two layers.

Answer:

lipid bilayer