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.
A publicly traded company is one which has shares of stock traded on the open market. 1  Private companies, on the other hand, do not have shares available for public purchase. Private companies may be owned by an individual, a family, a partnership, employees, or a small group of investors. To illustrate the difference, consider Hershey and Mars, two of the largest candy companies in the world. The late Milton Hersheyâs chocolate business is publicly traded on the New York Stock Exchange.