How are cells able to respond to signal molecule, that are too large to enter the cytoplasm?

By the ligand receptors on the surface of the cell membrane. How do transport proteins make it easier for certain molecules to diffuse across a membrane.  

the binding of a signaling molecule, or ligand, to its receiving molecule, or receptor.

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls

layer 3 is younger than layer 6.