The endoplasmic reticulum, or ER, and Golgi apparatus, prepare molecules, including proteins, hormones and lipids, and package them in vesicles for transport. Rough ER is studded with ribosomes that synthesize proteins, while the smooth ER manufactures lipids.
Explanation:
Simple Diffusion across the Cell (Plasma) Membrane The structure of the lipid bilayer allows only small, non-polar substances such as oxygen and carbon dioxide to pass through the cell membrane, down their concentration gradient, by simple diffusion.
Make sure you are eye level with the meniscus of the liquid level, and measure to the bottom of the meniscus.
