What is meant by the following statement about the cell membrane? the cell membrane is said to be semipermeable.

The cell membrane or a plasma membrane is a semipermeable membrane which means that this is a layer that allows only certain molecules that can pass through it. This allows the cells to keep their materials and the contents parted from the environment and from the other cells. This also makes the phospholipid bilayer an outstanding semipermeable membrane and protects the intracellular organelles from the environment that is outside from the cell.

ι вєℓινє тнє αиѕωєя тσ уσυя qυєѕтισи ιѕ в. ℓуѕσѕσмє

ι нσρє тнαт ι ¢συℓ∂ нєℓρ уσυ.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.