Quality Assurance (QA) Associate Salary. Average Quality Assurance Associates in the United States make around $49K per year. Cash earnings for Quality Assurance Associates â including $5K in bonuses and $6K in profit sharing proceeds near the top of the pay scale â generally stretch from $27K to $67K depending on individual performance.
Facilitated diffusion is the flow of molecules down a concentration gradient, across a membrane, but requires the help of a protein. There are two categories of proteins that assist facilitated diffusion: carrier proteins and channel proteins. Carrier proteins are like taxi cabs in a cell membrane.
Best Answer: Nonpolar and lipid-soluble substances diffuse directly through the lipid bilayer. Such substances include oxygen, carbon dioxide, and fat-soluble vitamins. In facilitated diffusion, molecules are passively transported using carriers or channels.Examples include glucose, ions, and water.est Answer: Nonpolar and lipid-soluble substances diffuse directly through the lipid bilayer. Such substances include oxygen, carbon dioxide, and fat-soluble vitamins. In facilitated diffusion, molecules are passively transported using carriers or channels. Examples include glucose, ions, and water.