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.
Olmsted Falls, Ohio. Olmsted Falls is a city in Cuyahoga County, Ohio, United States, and a southwestern suburb of Cleveland. The population was 9,024 at the 2010 census. The cityâs main business district is located at the corners of Bagley and Columbia Roads, and contains the Grand Pacific Junction, a historic and pedestrian friendly shopping district.