The rate of passive transport depends on the permeability of the cell membrane, which, in turn, depends on the organization and characteristics of the membrane lipids and proteins. The four main kinds of passive transport are diffusion, facilitated diffusion, filtration and osmosis.
DEFINITION of 'Privately Owned'. A company that is not publicly traded on a securities exchange. The majority of companies are privately owned, usually by either one individual or by a small group of individuals. Although offering securities for sale to the public can be a good way to obtain large amounts of financing, public ownership requires considerable effort to ensure compliance with securities regulations.
Limited liability company. A limited liability company (LLC) is the United States-specific form of a private limited company. It is a business structure that combines the pass-through taxation of a partnership or sole proprietorship with the limited liability of a corporation.