The cell membrane is composed of a phospholipid bilayer. Because it is made of lipids, they are non-polar molecules. That means that other non-polar molecules can easily pass through. In addition to other non-polar molecules, small, uncharged molecules like water, glycerol, ethanol can also pass through without the use of channel or carrier proteins. <span />
When an active cold front over takes a warm front is creates tornadoes.
Ribosomes, mitochondria, ER and chloroplast.
The leaf because it is the major structure of photosynthesis in a plant.
