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.
It has been said often that private companies seek to minimize the tax bite, while public companies seek to increase profits for shareholders. The popular misconception is that privately-held companies are small and of little interest. In fact, there are many big-name companies that are also privately held-check out the Forbes.com list of the largest private companies in 2006. (For further reading on this subject, check out Policing The Securities Market: An Overview Of The SEC .). RELATED FAQS.