can someone explain active transport and passive transport?

Answer 1

Passive transport involves carriers, channels, or direct diffusion through a membrane.
Examples of passive transport include
·Simple diffusion
·Channel diffusion
·Facilitated diffusion
In active transport it is possible to go against the concentration gradient.
In active transport, a source of energy is required to move the carrier and its materials.

Primary Active Transport directly uses ATP. An example of primary active transport is the sodium pump.
Secondary active transport does not directly use ATP.
It takes advantage of a previously existing concentration gradient (via carriers).

An example of the body needing to move against the concentration gradient
can be found in looking at glucose in the intestine.

Answer 2

Passive transport is the movement of particles down the concentration gradient, with no energy needed.
Active transport is the movement of particles against the concentration gradient, energy (usually ATP in the body) is needed for this.
Both are types of diffusion. One person who said passive transport needs channels, carriers etc is wrong as this only applies to facilitated diffusion, not all types of passive transport. Passive transport doesnt even need to be across a membrane, for example its how smells travel in the air :)

Answer 3

one requires the input of energy(Active) and one occurs due to simple diffusion(passive). within these, there are quite a bit more subdivisions of the type of transport that can occur but thats basically the diff.

Answer 4

Several people have answered similar question few days ago. I also participated please take a look:

http://answers.yahoo.com/question/index;_ylt=AsBVV4BrnT_JiUeq5BIyLUrsy6IX?qid=20061214092432AADjcl9&show=7#profile-info-35359787f8eaef350008a9e71b0118d3aa