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.
Passive transport of molecules A membrane can allow molecules to be passively transported through it in three ways: diffusion, osmosis, and filtration. Diffusion: Sometimes organisms need to move molecules from an area where they are highly concentrated to an area where the molecules are less concentrated.