Neutral molecules are transpoed by: (A) Porin channels, (B) Ionophores, (C) Simple diffusion, (D) None of the above
Answer is C. Simple diffusion occurs from higher to lower concentration. This does not require any energy. It is a very slow process.Diffusion of gases such as O2, CO2, NO and CO occurs at a rate that is solely dependent upon concentration gradients.Lipophilic molecules will also diffuse across membranes at a rate that is directly propoional to the solubility of the compound in the membrane.Ref: D M Vasudevan 7th edition Page no: 17