The cell membrane is selectively permeable because of its molecular structure. Based on this, which one of these would not diffuse directly through the cell membrane

A) macromolecules

Explanation:

guessed got it right

The large molecules like proteins composed of more than 1000 amino acid, mRNA molecules

Explanation:

The cell membrane of a cell is composed of the amphipathic molecules called lipids. The phospholipids are arranged in a way that their inner side is always hydrophobic therefore thy are considered hydrophobic molecules.

The hydrophobic molecules can diffuse easily and the small molecule can easily pass through the cell membrane but it restricts the entry of the larger molecules like the large proteins and the nucleic acid which can be diffused only with the process of either facilitated diffusion or the endocytosis or exocytosis.

Thus, the large molecules like proteins composed of more than 1000 amino acid, mRNA molecules are correct.