how do carrier proteins recognize substances to transport in active transport?

Answer 1

Proteins have unique shapes: Look at them here https://www.google.com/search?q=protein+shapes&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=k5UxT-LmO9KFsAKFsImbBw&biw=1280&bih=799&sei=l5UxT6yDIsz0sQL3-Mn-Bg

The protein receptors have a mirror image shape, at least for a portion of the protein, which allows it to "latch" on and hold the protein. Other proteins cant latch on, as they are different shapes, and wont fit.

Answer 2

http://www.google.com/search?q=protein+shapes&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=k5UxT-LmO9KFsAKFsImbBw&biw=1280&bih=799&sei=l5UxT6yDIsz0sQL3-Mn-Bg

Answer 3

Thank you Bobpursley.

Answer 4

And Ms.Sue.