What are the flattened sacks Flattened sacks of membranes involved in the packaging and export of molecules synthesized in the cell?
Many highly reactive molecules can affect the cell membranes negatively by modifying the chemical structure of the double layer of lipids that constitute most of these membranes. The most reactive of these molecules are strong oxidants, which can damage other molecules and the cell structures of which they are a part. Phosphorous is an essential nutrient, as it assists and strengthens energy metabolism, DNA structure, and cell membranes. Zinc is both an antioxidant enzyme co-factor…
Semipermeable membranes are used in osmosis. Semipermeable membranes let some molecules pass through them but not others, so they are partially or semi permeable. For example, the membrane may let smaller size molecules pass though but block larger molecules sort of like a sifter. Thus the two molecular substances can be separated.
Plasma membranes are described as being differentially permeable because they select what substances can pass through and what can not. Their behaviour is different for each substance. For example, the membranes will allow molecules such as water, carbon dioxide, oxygen and various small molecules to pass through. Larger molecules such as glucose and various ions are unable to permeate.