Figure 1. Types of movement across membranes. Molecules can diffuse across a. membrane down a concentration gradient without the aid of a protein or the input of. energy. Passive and active transport require membrane transport proteins. Channel. proteins carry out passive transport, but carrier proteins can carry out passive or active. transport.
Akron, Iowa. Akron is a city in Plymouth County, Iowa, United States. The population was 1,486 at the 2010 census.
Akron, Ohio. Akron /ËÃ¦krÉn/ is the fifth-largest city in the U.S. state of Ohio and is the county seat of Summit County. It is located on the western edge of the Glaciated Allegheny Plateau, approximately 39 miles (63 km) south of Lake Erie.