Which type of protein binds a ligand on the cell surface or within cells, often initiating a downstream signaling cascade or altering gene transcription?

The type of protein that binds a ligand on the cell surface or within cells are transmembrane receptors. These proteins have 3 domains: an extracellular part that does the binding, a hydrophobic domain that extends through the membrane, and an intracellular region that transmits the signal. The most common membrane-anchored receptors are: G protein-coupled receptors, receptor tyrosine kinases, and ligand-gated ion channels.

answer; /// i believe the correct answer is (reactants);

spiders belong to a group of arachnids.

arachnids have the following traits :

they have two body parts.

they have eight legs unlike insects which have 6 legs.

they have no wings.

these traits distinguish them from insects.

the information that antonio is doubting us the statement that spiders differences are as a result of being first to evolve.

this is because the evolution of one species is independent of the other species.