rapid chemical reaction of two or more substances with a characteristic liberation of heat and light; it is commonly called burning. The burning of a fuel (e.g., wood, coal, oil, or natural gas) in air is a familiar example of combustion.n its broad definition, combustion includes fast exothermic chemical reactions, generally in the gas phase but not excluding the reaction of solid carbon with a gaseous oxidant. Flames represent combustion reactions that can propagate through space at subsonic velocity and are accompanied by the emission of light.
They have a hydrophilic phosphate head and two hydrophobic hydrocarbon tails. Cell membranes are made up of a double layer of these phospholipid molecules. This is because in water the hydrophilic heads will face the water while the hydrophobic tails will be in the center because they face away from the water.The phospholipid bilayer makes the membrane very stable but also allows flexibility.hospholipid molecules make up the cell membrane and are hydrophilic (attracted to water) as well as hydrophobic (not attracted to water but are attracted to other hydrophobic tails).
The hydrophilic phosphate heads like water, so they touch the inside and the outside of the cell where the environments are aqueous. The fatty acid tails form a hydrophobic region in the middle, which is free of water.This cell membrane helps in structuring the cell and also controls which substances can cross it.o do hydrophilic molecules. Therefore, the hydrophobic tails of a phospholipid would want to stay with the oil layer of the salad dressing, while the hydrophilic head of the phospholipid would be attracted to the water layer. It would look like the phospholipid was doing a hand stand in the salad dressing.