Which type of molecule makes up the double layer of a cell membrane? a) carbohydrate b) lipid c) nucleic acid d) protein

B) lipid

Explanation:

The molecule that makes up the double layer of a cell membrane is the lipid. The lipids are the biomolecules which are soluble in non-polar solvents. The lipids form a semipermeable membrane. The lipid bilayer allows the passage of small hydrophobic molecules and gases like carbon dioxide and oxygen across the cell. Small polar molecules such as water and ethanol also pass through the membrane but slowly. It restricts the diffusion of large molecules, ions, amino acids and sugars across the cell membrane.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.